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The Mecyclothorax beetles (Coleoptera, Carabidae, Moriomorphini) of Haleakala-, Maui: Keystone of a hyperdiverse Hawaiian radiation
expand article infoJames K. Liebherr
‡ Cornell University, Ithaca, United States of America
Open Access

Abstract

The Mecyclothorax carabid beetle fauna of Haleakalā volcano, Maui Island, Hawai‘i is taxonomically revised, with 116 species precinctive to Haleakalā recognized, 74 newly described. Species are classified into 14 species groups, with the newly described species arrayed as follows: 1, M. constrictus group with M. perseveratus sp. n.; 2, M. obscuricornis group with M. notobscuricornis sp. n., M. mordax sp. n., M. mordicus sp. n., M. manducus sp. n., M. ambulatus sp. n., M. montanus sp. n., M. waikamoi sp. n., M. poouli sp. n., and M. ahulili sp. n.; 3, M. robustus group with M. affinis sp. n., M. anchisteus sp. n., M. consanguineus sp. n., M. antaeus sp. n., M. cymindulus sp. n., and M. haydeni sp. n.; 4, M. interruptus group with M. bradycelloides sp. n., M. anthracinus sp. n., M. arthuri sp. n., M. medeirosi sp. n., M. inconscriptus sp. n., and M. foveolatus sp. n.; 5, M. sobrinus group with M. foveopunctatus sp. n.; 6, M. ovipennis group with M. subtilis Britton & Liebherr, sp. n., M. patulus sp. n., M. patagiatus sp. n., M. strigosus sp. n., M. takumiae sp. n., M. parapicalis sp. n., M. mauiae sp. n., M. subternus sp. n., M. flaviventris sp. n., M. cordaticollaris sp. n., and M. krushelnyckyi sp. n.; 7, M. argutor group with M. ommatoplax sp. n., M. semistriatus sp. n., M. refulgens sp. n., M. argutulus sp. n., M. planipennis sp. n., M. planatus sp. n., and M. argutuloides sp. n.; 8, M. microps group with M. major sp. n., M. xestos sp. n., M. orbiculus sp. n., and M. contractus sp. n.; 9, M. scaritoides group with M. scarites sp. n., M. timberlakei sp. n., M. crassuloides sp. n., M. crassulus sp. n., M. gracilicollis sp. n., and M. dispar sp. n.; 10, M. haleakalae group with M. reiteratus sp. n., M. splendidus sp. n., M. bacrionis sp. n., and M. simpulum sp. n.; 11, M. vitreus group with M. kipwilli sp. n., M. kipahulu sp. n., M. kaumakani sp. n., and M. kuiki sp. n.; 12, M. montivagus group with M. rex sp. n.; 13, M. ducalis group with M. aquilus sp. n., M. invisitatus sp. n., M. longidux sp. n., and M. brevidux sp. n.; and 14, M. palustris group with M. hephaestoides sp. n., M. oculellus sp. n., M. bicoloris sp. n., M. bicoloratus sp. n., M. bilobatus sp. n., M. palustroides sp. n., M. filipoides sp. n., M. nanunctus sp. n., M. tauberorum sp. n., and M. pau sp. n. Mecyclothorax integer Sharp, stat. n. is recognized as a species distinct from M. interruptus Sharp. Because type series for species described by Blackburn, Karsch, and Sharp are most often divided among geographically remote collections, lectotypes are designated to stabilize the nomenclature. The radiation includes numerous cryptic sibling species best diagnosed using male genitalia, and photographs are used to represent the male genitalic variability observed among numerous dissected individuals. The large number of new species is based on substantial new collections made from all quarters of the mountain. The dense geographic sampling allows fine-scale discrimination of species boundaries, elucidating the geographic disjunctions that are associated with speciation within this hyperdiverse radiation. Disjunctions between closely related species precinctive to various areas of the mountain are not congruent across the different lineages of the radiation, indicating differential responses by the various lineages to past geological and geographical events. Of the 62 1’ latitude × 1’ longitude grid cells on Haleakalā that are occupied by Mecyclothorax beetles, 22 house 10 or more species, and 9 house 20 or more species. This substantial level of sympatry, associated with occupation of diverse microhabitats by these beetles, provides ample information useful for monitoring biodiversity of the natural areas of Haleakalā.

Keywords

Allopatric speciation, biodiversity, biogeography, genitalic evolution, revisionary systematics

Introduction

The Hawaiian Islands are home to a remarkable assemblage of carabid beetles, unique in the World for its composition, as well for its inordinate species-level diversity. Like the Hawaiian biota at large (Zimmerman 1970), the native Carabidae are exceedingly disharmonic, being represented by beetles assignable to only three tribes—Bembidiini, Moriomorphini, and Platynini—of the total 110 tribes currently recognized in the family (Bousquet 2012). However each of these tribal taxa are represented by numerous species native to Hawai‘i, all of them geographically restricted to the archipelago. The Platynini are represented by 133 extant and 7 extinct species of the endemic genus Blackburnia Sharp, with these species distributed on all of the current high islands; Kaua‘i, O‘ahu, Moloka‘i, Lāna‘i, Maui and Hawai‘i Island (Liebherr and Zimmerman 2000, Liebherr and Porch 2015). The radiation is monophyletic (Liebherr and Zimmerman 1998), with closest relatives in Australia (Liebherr 2005a). The Bembidiini of Hawai‘i include 23 native species of Bembidion Latreille (Liebherr 2008a) representing two colonization events, both emanating from New Zealand (Liebherr and Maddison 2013). Several other bembidiine genera also include Hawaiian species—Tachys Stephens sensu lato, Lymnastis Motschulsky, and Typhlonesiotes Jeannel (Britton 1948a)—though only one to several species have evolved in each of these colonizing lineages. However it is the Hawaiian representatives of the Moriomorphini that set the standard for diversity. In all, based on this revision, there are 239 native species of Mecyclothorax Sharp known from Hawai‘i. Their collective distribution differs from the distributional pattern ascribed to progressive colonization of the Hawaiian Island chain (Gillespie and Roderick 2002), as the greatest diversity, by far, resides on Haleakalā, Maui, where 116 species are known. Conversely, the genus is not represented on Kaua‘i, the oldest subaerial high island. Fitting with that absence, the O‘ahu Mecyclothorax fauna is attenuated, with only a few species groups and 20 species occurring on the island (Liebherr 2009a), whereas the present-day fragments of Maui Nui support more species—Moloka‘i with 43 (Liebherr 2007) and West Maui with 27 (Liebherr 2011)—complementing the great diversity of Haleakalā. The Mecyclothorax fauna of the geologically youngest island of Hawai‘i (Liebherr 2008b) comprises 30 species, all members of species groups that have diversified on Haleakalā. The Hawaiian radiation is monophyletic based on morphological characters (Britton 1948b, Liebherr 2013), with the most generalized species, M. montivagus (Blackburn) residing in open shrubland on the lee slopes of Haleakalā.

The Mecyclothorax species of Haleakalā are taxonomically revised below. By the numbers, Hawaiian Mecyclothorax are predominantly rainforest species, with the highest diversity in the windward forests of Waikamoi, Hanawī, and Kīpahulu Valley (Fig. 1). Thus the 116 known species are concentrated into only a portion of Haleakalā’s 1,440 km2 surface area. This biotic concentration is evidenced by extremely high levels of sympatry among the various species, with more than 20 species commonly recorded from a forested area of 1’ latitude × 1’ longitude. This level of diversity has confounded past attempts to identify specimens representing this genus, especially because only about one-third of the Haleakalā species were described, either in the premier Fauna Hawaiiensis (Sharp 1903), or the subsequent revision by Britton (1948b). This revision attempts to rectify that problem by providing numerous photographs to document the morphological diversity of this fauna. The amount of biological information inherent in such large radiations is essentially limitless, as it can be viewed in light of phylogenetic relationships and thus become relevant to hypotheses regarding speciation or selection, or be joined with geographical or ecological information to assist conservation management.

Figure 1.

Map of Maui Island, Hawai‘i labeled with regions of Haleakalā volcano mentioned in text.

Materials and methods

Haleakalā. Thomas Blackburn wrote “The eastern end of Maui is, in my opinion, the head-quarters of the insect fauna of the archipelago. It is formed entirely by that gigantic mountain Haleakala ... (Blackburn 1885: 205).” At over 3000 m tall, the mountain supports many habitats that are defined by topographic parameters such as altitude and windward aspect, as well as geological factors such as the recency of volcanic lava flows (Sherrod et al. 2007). From available specimens, both recently and historically collected, we can surmise that Mecyclothorax beetles occupied much of the gigantic mountain. There are historical records from as low as 450 m elevation (Fig. 6), and a well-developed fauna in Haleakalā Crater (Fig. 2A) and at the 3000 m summit in areas of Sophora shrubland or alpine aeolian desert. Recent records from such marginal carabid habitats are few, and therefore quite valuable, with most beetle collections coming from rainforest habitats on or adjoining the windward, i.e. northeastern and eastern upper slopes of the mountain. Nevertheless, moisture is also available to the leeward south slope either during episodes of southerly, or kona weather, or by uphill convection of moist marine air leading to the development of fog, and condensation of water on plant surfaces (Juvic and Nullet 1995).

Figure 2.

Views of Haleakalā volcano. A Haleakalā Crater looking northwest toward Hanakauhi. Photo <br/> taken from Sliding Sands Trail B Kīpahulu Valley from Kuiki, with Kaumakani in the right rear distance and Waiho‘i Valley to its left. Ridge within Kīpahulu Valley is Central Pali.

In order to place the specimens used as the basis for this revision in an ecological context, an outline of the major habitat formations and biogeographic areas across the windward face is presented. This synopsis necessarily takes a coleopterist’s eye view, but will hopefully allow those who venture into the field the ability to know when they are in the same situations that resulted in the taxonomic material currently in hand. Conversely, any findings made outside the situations presented here will add to what is known about where and how these beetles live. For an overview of the botanical communities in Hawai‘i, with special emphasis on those in Haleakalā, the reader should consult Gagné and Cuddihy (1990). Their classification of botanical formations is followed throughout this revision. The outline below commences with the Waikamoi area, the best collected area as it was the only rainforest accessible to 19th Century collectors such as T. Blackburn and R.C.L. Perkins. This botanically rich and geographically complex area remains accessible and was visited on numerous occasions for this study. The outline then proceeds clockwise through the other identified areas of Haleakalā (Fig. 1).

Waikamoi. Forests of this area are dominated by koa (Acacia koa) and ‘ōhi‘a (Metrosideros polymorpha), with intact, accessible forest habitats spanning 900–2000 m elevation. Though the stream drainages in this area lie along the western, leeward edge of Haleakalā’s windward face, rainfall is abundant and the gulches may be very deep. The forest is wetter from rainfall at lower elevations, with ‘Ōhi‘a/Hāpu‘u Wet Forest present from 900–1400 m. At higher elevations koa becomes more prevalent, with large trees dominating the forest at 1500 m elevation near the western forest edge (Fig. 3A). The koa forest is well developed near Ukulele Camp (Site) at ~1600 m (5360 ft.) elevation (USGS 1983). This site was carefully collected because it served as R.C.L. Perkins’ base camp (Perkins 1894, 1896a, b). The streams that run through this area within whose gulches Mecyclothorax beetles were collected include (west to east): Kahakapao, Opana, Waikamoi, Haipua‘ena, and Honomanu. The Mecyclothorax fauna of this area includes several ecologically defined subfaunas. The most generalized component of the fauna is associated with ‘ōhi‘a trees and associated moss growing on trunks, in branch crotches, or on exposed air roots (Fig. 3B). Many of these species, such as M. consanguineus, M. filipoides, M. iteratus, M. kipwilli, M. ovipennis, M. perstriatus, and M. robustus may also occur on koa, though the number of collecting occurrences of these species is small. Conversely, there are species in this area that are predominantly associated with koa; e.g. M. haleakalae, M. macrops, and M. vitreus. These beetles occur under bark flaps during daytime, and forage on tree branches during nighttime.

The third component is a terrestrial suite of species that occur predominantly in association with leaf litter on well-drained soil, most often in association with koa forest along the drier western and upper elevational edges of the forest. These species include M. inaequalis, M. longulus, M. multipunctatus, M. obscuricornis, M. sobrinus, and M. unctus. A terrestrial species—e.g. M. unctus—may also be found along stream edges, though this habitat is rarely occupied by Mecyclothorax beetles. The combined diversity of these different guilds is very large, with an extensive number of species precinctive to this portion of the mountain. In all, 25 species are restricted to forests west of Ko‘olau Gap. Even though Blackburn and Perkins necessarily centered their collecting here, 14 of these endemics are newly described below.

Figure 3.

Forests of Haleakalā volcano. A Acacia koa (koa) tree in mesic montane forest of Waikamoi Nature Conservancy Preserve, Honomanu drainage, 1850 m elevation (photo courtesy D.A. Polhemus) B Moss-covered Metrosideros polymorpha (‘ōhi‘a) tree next to Kuhiwa Stream, 1600 m elevation C Koa Mesic Forest in Kaupō Gap, 1500 m elevation.

Ko‘olau Gap/Ke‘anae Valley. East of the Waikamoi forests and gulches lies this broad Pleistocene erosional feature with secondary volcanic vents (Sherrod et al. 2006). The valley floor is very wet, with standing pools of water surrounded by low-stature ridges bearing open forest vegetation consisting of ‘ōhi‘a and ōlapa (Cheirodendron spp.) trees. Cibotium tree ferns (hāpu‘u) are also prevalent, often growing on downed ‘ōhi‘a nurse logs. The open understory sampled for Mecyclothorax beetles is covered with dense native ‘ākala (Rubus hawaiensis). In keeping with the ~1000 year old flows within Ko‘olau Gap (Sherrod et al. 2006), there are no species precinctive to this area, and populations here may represent Waikamoi-centered species, e.g. M. interruptus (Fig. 51) or M. rex (Fig. 130), widespread windward species such as M. mauiae (Fig. 71) or M. iteratus (Fig. 106), or western-limital populations of species otherwise known from Hanawī and the Hāna Bogs to the east; e.g. M. bacrionis (Fig. 112) and M. pau (Fig. 163).

Hanawī. As circumscribed in this treatment, Hanawī is geographically broad, including all drainages between Ke‘anae Valley on the west, and Helele‘ike‘oha Stream on the east. The area receives abundant rainfall, with the weather station on Kuhiwa Stream receiving the highest rainfall amounts on the windward face (Stearns and MacDonald 1942). The area is ecologically disparate, with a broad area centered on Kopili‘ula Stream that is devoid of closed forest, the ‘ōhi‘a trees experiencing significant dieback (Holt 1983). Mecyclothorax beetles were sampled between 1100–1200 m elevation in an area with extensive, 1.5–2 m tall uluhe fern (Dicranopteris) banks covering the ground, and many downed ‘ōhi‘a logs, with scattered emergent koa trees the major standing woody vegetation. This formation best corresponds to the Lowland Wet ‘Ōhi‘a/Uluhe Fern Forest formation of Gagné and Cuddihy (1990: 89), but with the ‘ōhi‘a trees removed by dieback. Further east the country is continuously wooded, with Wet ‘Ōhi‘a/Hāpu‘u (Metrosideros/Cibotium) Forest at lower elevations, and more dominant ‘ōhi‘a and ōlapa (Cheirodendron spp.) at higher elevations. The extensive rainfall and condensed fog and mist provide abundant moisture supporting development of substantial moss mats on ‘ōhi‘a trees (Fig. 3B). Many beetles reside in these mats, with the best means to sample these epiphytic growths being the use of pyrethrin fog. Fewer beetles are associated with ground-level microhabitats due to the extensive runoff over the rocky and muddy surface. The soil surface suffered prior to our visits from the depredations of feral pigs (Sus scrofa), with their rooting extensively damaging the forest understory plants. Infrastructure in this area includes two cabins established to support study of the formerly endangered and now extinct Po‘o uli (Melamprosops phaeosoma Casey and Jacoby), a distinctive Hawaiian honeycreeper of the avian family Fringillidae. Elevational transects were established to facilitate study of bird population levels in this area (Simon et al. 2002) and these provided the means to move vertically on the mountain while sampling for insects. The Kuhiwa and Helele‘ike‘oha Stream drainages were sampled in this area, the former from its headwaters down to 880 m elevation. Seven Mecyclothorax species are known to be precinctive to the Hanawī region as defined here, and another five species have distributions centered here but extending to neighboring areas such as Kīpahulu Valley or the Hāna Bogs.

Hāna Bogs. This poorly drained tableland lies above and to the east of the eastern Hanawī area, and is bordered to the east by Waiho‘i Valley, to the south by Kīpahulu Valley, and to the southwest by Kalapawili Ridge, the northern summit ridge of Haleakalā Crater. The vegetation is classified as the ‘Ōhi‘a Montane Wet Mixed Community (Gagné and Cuddihy 1990), with open bog surfaces populated with sedges and grasses. These develop hummocks that can support woody vegetation—‘ōhi‘a, ōlapa, and the stunning Lobelias—with the margins of the bogs hemmed in by small stature, 5–7 m tall, ‘ōhi‘a trees (Fig. 4A). Beetles were encountered in epiphytic mosses growing on the emergent woody vegetation. Given the very wet, in some instances flowing bog surfaces, movement of individual brachypterous beetles must occur only during drier periods of the year. Endemism is rather low here for Mecyclothorax, with only M. medeirosi restricted to this formation. However several species known from Hanawī and Kīpahulu Valley also occur here, elevating Mecyclothorax diversity somewhat.

Figure 4.

Moist habitats of Haleakalā volcano. A New Greensword Bog in the Hāna Bogs area, 1850 m elevation B Wet montane forest ESE Kuiki along the western rim of Kīpahulu Valley, 1850 m.

Kīpahulu Valley. With its head lying southwest of the Hāna Bogs tableland, Kīpahulu Valley extends broadly southeastwardly to the sea, affording a continuous transect of native forest from Mauka Ridge at 2050 m elevation, to the deterioration of native forest approaching 600 m elevation. The valley floor consists of recent, Hāna volcanic flows (Sherrod et al. 2007) with a flow along the southern half of the valley overlying an older flow that defines the northern half of the valley floor. The Central Pali at their junction can be travelled, allowing access to habitats at different elevations (Fig. 2B). The higher elevations—1900–2000 m elevation—support ‘Ōhi‘a (Metrosideros) Montane Wet Forest (Gagné and Cuddihy 1990), a low stature formation that is composed almost exclusively of ‘ōhi‘a, with the 5–8 m tall trees covered abundantly with epiphytic mosses and lichens. At mid-elevations—1200–1500 m elevation—the forests support koa and hāpu‘u (Cibotium) tree ferns as well as ‘ōhi‘a, producing a more complex forest mosaic. At the bottom of the transect—600–900 m elevation—the forest is classified as ‘Ōhi‘a Lowland Wet Forest (Gagné and Cuddihy 1990). At and below this elevational level the forest becomes heavily invaded with strawberry guava (Psidium cattleianum) and non-native grasses, and native insects are not found. Through collaboration with Drs. A. Medeiros and D. Polhemus, the entire elevational transect was sampled for Mecyclothorax beetles. Based on the material in hand, endemism is high, with nine species known only from within Kīpahulu Valley, and seven more species nearly precinctive to the valley, as they also include populations in adjacent areas such as Hanawī, the eastern reaches of Haleakalā Crater, and Kaupō Gap. Species are subdivided by elevation, with high elevation specialists including M. anchisteus (Fig. 32), M. refulgens (Fig. 85), and M. kipahulu (Fig. 121). Conversely M. dispar is known only from 1200 m elevation (Fig. 101), and M. aquilus only from 900 m (Fig. 135). Other Kīpahulu precinctives—e.g. M. manducus (Fig. 21) and M. cymindulus (Fig. 40)—are known from a range of elevations in the valley, but have yet to be found in adjacent areas.

Manawainui Planeze. Bounded on the north by Kīpahulu Valley and on the west by Kaupō Gap, this pie-slice shaped planeze of Kula Volcanics—0.228 Myr old (Sherrod et al. 2003)—is exceedingly discrete. At 2100 m elevation near its northwest summit of Kuiki, the habitat is open ‘ōhi‘a woodland, with individual trees isolated by grasses (Fig. 5A). Copses of small ‘ōhi‘a trees also occur, with the small-stemmed plants bearing epiphytic mosses, and the ground densely covered with slowly decaying myrtaceous leaf litter (Fig. 5B). Mecyclothorax beetles have been collected within these shaded situations, including three species precinctive to Manawainui Planeze; M. mordax (Fig. 19), M. antaeus (Fig. 36), and M. gracilicollis (Fig. 101). A fourth geographically restricted species also occurs here; M. kuiki also found in the Hāna Bogs (Fig. 121). Moving downward in elevation brings one into the ‘Ōhi‘a (Metrosideros) Montane Wet Forest at 1800–1900 m elevation (Fig. 4B). Here 5–8 m tall ‘ōhi‘a trees dominate with the occasional ōlapa (Cheirodendron), and understory shrubs including pilo (Coprosma) and pūkiawe (Leptecophylla) (Gagné and Cuddihy 1990). Mecyclothorax strigosus has only been collected at this elevation on the planeze (Fig. 64). Further downhill—1600–1700 m elevation—this formation is complemented by hāpu‘u (Cibotium) tree ferns, with the ‘ōhi‘a trees of larger stature. Mecyclothorax ahulili (Fig. 25) and M. kaumakani (Fig. 121) have been collected in this elevational zone near Puu Ahulili.

Figure 5.

Vegetation in vicinity of Kuiki. A Open ‘Ōhi‘a Savannah above timber line near Kuiki summit, 2100 m elevation B Elfin ‘Ōhi‘a Forest just below timber line showing well-drained leaf-litter humus layer in “rooms" within the low forest canopy.

Haleakalā Crater and Kaupō Gap. These two areas are floored by very young volcanic deposits, ranging from only about 1000 years within the crater, and about 8000 years along the eastern margin of Kaupō Gap (Sherrod et al. 2006), strongly suggesting that any species currently known only from these areas evolved either somewhere else, or within the bounds of these features, with their species’ members then dispersing to colonize the newer ground upon which they were collected during this study. The western crater is drier, and therefore covered with a dry shrubland formation (Fig. 2A). Few specimens have been collected in this area, though those that have been—e.g. M. parapicalis endemic to the western crater—suggest that the area should be sampled more thoroughly. The eastern crater margin at Paliku lies at about 2000 m elevation directly under the headwall of Kīpahulu Valley, with veils of trade-wind moisture spilling onto the area from the eastwardly looming Kīpahulu summit ridge. This moisture source supports a mesic savannah biota, with native Rubus (‘ākala) abundant, and copses of ōlapa (Cheirodendron) occurring amongst the shrubland plants. This situation is remarkably beneficent to Mecyclothorax beetles, with two species known only from this site—M. takumiae (Fig. 67) and M. major (Fig. 94), and a third found here and also further south in Kaupō Gap; M. inconscriptus (Fig. 51). Other species collected at Paliku also live in much wetter locales; e.g. M. arthuri also known from Kuiki on the Manawainui Planeze and from the head of Kīpahulu Valley (Fig. 51), and M. planipennis from those sites plus Waiho‘i Valley (Fig. 86). Progressing south from Paliku into Kaupō Gap, one enters Koa Mesic Forest near 1500 m elevation. Mecyclothorax cordaticollaris (Fig. 77) is known only from this geographically restricted koa forest, and M. simpulum is found here and also at lower elevations in Kīpahulu Valley (Fig. 112).

Kahikinui.—Everything we know about the Mecyclothorax fauna of the immense south face of Haleakalā, much included in the Kahikinui district, comes from the efforts of Drs. Paul Krushelnycky and Robert Peck. Known Mecyclothorax diversity in the Koa/‘Ōhi‘a Montane Mesic Forest that occurs on this slope amounts to four species—M. giffardi (Fig. 56), M. krushelnyckyi (Fig. 79), M. cordithorax (Fig. 89), and M. iteratus (Fig. 106)—with only M. krushelnyckyi restricted to Kahikinui. The koa/‘ōhi‘a forest has been seriously degraded by cattle (Bos taurus), goats (Capra hircus), and pigs (Sus scrofa), though mature koa and ‘ōhi‘a trees remain on the slope. The leeward site offers a possible locale for translocation of individuals of the endangered Maui Parrotbill (Pseudonestor xanthophrys: Family Fringillidae) (Mounce et al. 2015). Ongoing efforts to reestablish Koa/‘Ōhi‘a Forest in Kahikinui—specifically the Nakula Natural Area Reserve of the State of Hawai‘i—is intended to ensure the arthropod resource base required by the endangered birds (Peck et al. 2015). Such rehabilitation efforts may offer enhanced opportunities for all of the native fauna to develop populations on this face of Haleakalā.

Polipoli Springs. Situated on the southwest rift of Haleakalā, Polipoli Springs is an oasis of mesic forest vegetation at the boundary of the drier Kahikinui and Kula faces of the mountain. The original native Koa/‘Ōhi‘a Mesic Forest was degraded through grazing, with reforestation during the 1930s taking the form of numerous exotic trees planted in large plots as an experimental forest. Exotic tree species include Monterey Pine (Pinus radiata), Tropical Ash (Fraxinus hydei), and Coast Redwood (Sequoia sempervirens). The understory is open and dominated by Dryopteris wallachiana fern (laukahi). The exotic pine grows very well in the cloud zone at this elevation, with the trees unstable due to the ashy soil, resulting in extensive lodging, leading to large light gaps covered by downed logs. Even given the alien landscape, native Mecyclothorax beetles abound in the leaf litter, under stones near the spring sources, and under loose bark of downed trees (Liebherr 2005b). The species present here often represent southwest outpost populations of species also found in the dry habitats of the northern Kula face to the wetter forest habitats of the mountain’s windward side; e.g. M. irregularis (Fig. 48), M. ovipennis (Fig. 66), M. laetus (Fig. 74), and M. cordithorax (Fig. 89). More significantly, the beetles living here are precinctive to Polipoli, their ancestors presumably having survived the ecological holocaust of deforestation during the early 20th Century. These alien forest endemics are closely related to windward forest species found in Waikamoi; e.g. M. aeneipennis (Fig. 32), M. consobrinus (Fig. 59). A third biogeographic pattern is represented here by M. giffardi, a species also found on the drier leeward south face of Haleakalā (Fig. 56). From these patterns it can be concluded that the Polipoli area has continuously supported Mecyclothorax populations long enough for speciation to have occurred, and that the area still supports species that persist in the native Koa/‘Ōhi‘a Mesic Forest of Kahikinui.

Kula. The dry leeward face of Haleakalā that is accessible for entomological study consists of Montane Dry Shrubland, an open formation from 900–2700 m elevation dominated by small stature ‘ōhi‘a (Gagné and Cuddihy 1990), that grades into open māmane (Sophora) shrubland with Deschampsia bunchgrass in the higher elevations. Mecyclothorax beetles have occurred throughout this zone, with historical records of M. montivagus being from rather low elevations (Fig. 132). The higher māmane forest is dominated by M. cordithorax (Fig. 89), M. micans (Fig. 130), and M. montivagus (Fig. 132). Other montane species of the M. ovipennis group also occur in this area upwards to the bare, aeolian summit of Pu‘u ‘Ula‘ula; e.g. M. subconstrictus and M. nubicola (Fig. 79), and M. pusillus and M. rusticus (Fig. 80). Three of these four—M. subconstrictus, M. pusillus, and M. rusticus—were collected in large numbers only in the weeks after melt of an unusual snowcap during April (Perkins 1894). If populations of these species persist, their individuals may live cryptically within the soil for much of the year, or perhaps spend time in subterranean voids such as burrows of the Hawaiian Dark-rumped Petrel/‘Ua‘u (Pterodroma sandwichensis: Family Procellariidae). The upper Kula Face has been invaded by several alien species; Argentine Ant, Linepithema humile (Mayr), and a European carabid beetle imported via Oregon, Trechus obtusus Erichson (Liebherr and Takumi 2002, Liebherr and Krushelnycky 2007). Both the ant and alien carabid adversely impact native Mecyclothorax populations, suggesting another reason for the relative lack of recent collections of the high-altitude M. ovipennis group species.

Taxonomic material. This revision is based on the study of 7,623 specimens of Mecyclothorax collected on Haleakalā (Fig. 6) currently held in 15 institutions (Table 1). Historical material predominantly includes specimens collected by the Rev. Thomas Blackburn (summarized in Blackburn and Sharp 1885) and R. C. L. Perkins (Manning 1986). The bulk of Blackburn’s material was deposited in The Natural History Museum, London (BMNH), although some personally retained syntypes were subsequently deposited in the South Australian Museum, Adelaide. Perkins’ material was collected on behalf of the Fauna Hawaiiensis (Sharp 1903), with the collecting series divided between The Natural History Museum, London (BMNH) and the Bernice P. Bishop Museum, Honolulu (BPBM). A third smaller lot of material was collected by Otto Finsch, described by Karsch (1881) and deposited in the Museum für Naturkunde, Berlin (MNHU). Finsch’s specimens remained unlabeled except for lot number until taken on loan by the author. Subsequent to publication of the Fauna Hawaiiensis, Blackburn, Finsch, and Perkins material was exchanged with other major institutions in Canberra, Paris, and Milan. Because of this division of syntype series, and some genuine confusion of species in the divided material—some of Blackburn’s syntypes are misidentified—lectotypes have been designated for all species for which a holotype was not previously designated. Most lectotypes were labeled during a brief visit to The Natural History Museum. That visit’s brevity necessitated that the many paralectotypes were not so labeled. For material described in this revision, holotypes were chosen, when possible, from the historically earliest collections of the species. Where cryptic species are newly described here, necessitating use of male genitalia for firm identification, a male specimen, either dissected or with partially everted genitalia, has been chosen as holotype. Holotype data are presented in the text with verbatim transcriptions of the labels, including character spacing and a close approximation of font. Individual lines on labels are separated by slashes ( / ), separate labels by double slashes ( // ). Lectotype label transcription follows that protocol with the exception that label lines for BMNH lectotypes are not denoted. Paratype data are summarized from a specimen database, with redundant fields removed from adjacent records so as to minimize required text space. Holotypes are deposited in the institutions associated with the types’ collectors, except for specimens collected by R. Takumi Kaholoa‘a, Haleakala National Park, which are deposited at the Bishop Museum, Honolulu, where they are held in a secure type collection. Recently collected material forms the bulk of the taxonomic material, with most field specimens generated during expeditions in 1991, 1993, 1998, 1999, 2001, 2003, and 2005. Specimens from 1991 and 1993 were collected in ethyl acetate killing jars, and then held under ethyl acetate atmosphere in scintillation vials holding crumpled Kimwipes® tissues. Prior to preparation the ethyl acetate was allowed to evaporate, and specimens were placed in near boiling water as they were prepared as point-mounted specimens. Specimens from later years were either killed in ethyl acetate, held for a day in the kill jar, and then transferred to 70% ethanol (Liebherr), or collected directly into ethanol (Ewing, Polhemus). These specimens were point-mounted directly from ethanol.

Figure 6.

Distribution of localities on Haleakalā volcano from which Mecyclothorax beetles have been collected. Numbered localities isolated to the north of the main mass of localities were sites of historical collecting events.

Specimen repositories with numbers of specimens, and the collectors whose deposited material would be eligible for lectotypification in this revision. Nearly all lectotypes are designated using BMNH and MNHU material. For names of institutions and associated curators, see Acknowledgements.

Institutional Code No. Specimens Historical Collectors
ANIC 12 Perkins
BMNH 723 Blackburn, Perkins
BPBM 1,214 Perkins
CAS 392
CUIC 3,084
HALE 408
HDAC 8
HNHM 4
MNHN 29 Blackburn, Finsch, Perkins
MNHU 12 Finsch
MSNM 11 Perkins
NMNH 1,502
SAMA 9 Blackburn
UCRC 59
UHIM 147

Laboratory methods. Specimen preparation and dissection protocols are the same as those used for prior Hawaiian Mecyclothorax revisions (Liebherr 2007, 2008b, 2009a, 2009b, 2011). Briefly, both male and female specimens were relaxed in nearly boiling distilled water held in shell vials placed in a double boiler, the water containing a drop of Kodak Photo-Flo® detergent. For males, the aedeagal median lobe, associated parameres and 9th tergite were disassociated from the abdomen using minute nadeln mounted on wooden dowels. The genitalic apparatus was removed, cleared overnight in cold 10% KOH, deacidified in 10% acetic acid, and then placed in glycerine. If the male internal sac was to be everted using modified minuten nadeln, eversion was done while the dissection was soaking in KOH or acetic acid, as dehydration in glycerine made the sac more brittle and impossible to evert. Female dissections involved removal of the entire abdomen and clearing it overnight in cold 10% KOH. The female reproductive tract was removed from the abdomen by first tearing off the membranous tergites, then gently tearing the 8th laterotergites from the sclerotized abdominal ventrites. The reproductive tract assembly was deacidified briefly in dilute 10% acetic acid, then cleared and stained for approximately 10 minutes in a mixture of Kodak® Chlorazol Black stain suspended in methyl cellosolve. The dissection was placed in glycerine, and the various tracheae and defensive gland assemblies and associated sclerites removed from the gonocoxae and bursa copulatrix complex. This latter was mounted in glycerine on a microscope slide.

All male and female genitalic dissections were photographed using a Microptics (now Visionary Digital®) photographic apparatus employing a Nikon D1 camera, the K2 lens system, and a three-wand photographic strobe fiber-optic light source. All male aedeagal preparations were photographed at the same scale from a right-side view, augmented when appropriate with a ventral view. Aedeagal preparations with internal sac everted were photographed from the right side. In all, 562 male dissections representing 99 species, and 92 female dissections representing 85 species were photographed. For all newly described species at least one male specimen from each collecting series was dissected and photographed, with the photographs used to assist specimen assignment to species. Where necessary, multiple specimens per series were photographed, until all specimens could be assigned to species with confidence using both external and male-genitalic characters. Female dissections were photographed in ventral view however the 3-dimensional complexity of the gonocoxites and associated laterotergites required interpretive line drawings for those structures. To compose the line drawings, the photographed dissections were used to establish the outlines of major features of the gonocoxites, with the finer setational and sensillar features placed on the drawing by hand during examination of the dissection under phase contrast compound microscopy at magnifications of 100–400×. A calibrated ocular grid served to establish scaled dimensions for all photographs and drawings.

Descriptive conventions and characters. Species descriptions were generated in close consultation with a character matrix developed during extensive examination of specimens and scoring of characters. An initial list of characters, based on experience with the Society Islands Mecyclothorax fauna (Liebherr 2012a, 2012b, 2013), was augmented with additional characters as those were discovered among the Hawaiian species. All descriptions include a diagnosis that summarizes the salient characters that may be used to distinguish the species in question from all others. In some instances these characters are the same as those used in the dichotomous identification keys, though other characters also included may diagnose the particular species from those not sequentially adjacent in the key. All diagnoses also include two standard metrics: 1, standardized body length; and 2, the setal formula. Standardized body length is defined as the sum of three linear measurements: 1, the distance from the labral anterior margin to the cervical ridge, a transverse carina posterad the vertex; 2, the medial length of the pronotum; and 3, the elytral length defined as the distance from the base of the scutellum to the elytral apex, measured parallel to the suture. The setal formula was developed and used by Perrault (1984, 1986, 1988, 1989) as a shorthand to diagnose species and species groups for the Society Islands Mecyclothorax fauna. The setal formula consists of four numbers, abcd, defined as: a = the number of supraorbital setae each side of the head; b = the number of setae along the lateral margin of the pronotum; c = the number of dorsal elytral setae associated with elytral interval 3 on each elytron; d = the number of setae at the apex of each elytron. There may be either two (Fig. 7) or one supraorbital setae each side; if one it is the posterior seta that is present in Hawaiian species. There may be 0, one, or two lateral pronotal setae; if one it is always the lateral seta, as the basal seta is evolutionarily lost prior to loss of the lateral seta. Most species are characterized by two dorsal elytral setae each side, at approximated 0.3× and 0.6× the elytral length. The posterior seta is absent in some species, and both setae are absent in some others. The setae of the elytral apex include one—termed the apical seta—at the apex of elytral stria 2 just basad the longest point of the elytron, and a 2nd seta—the subapical seta—present in the 7th elytral stria mesad the subapical sinuation (Fig. 7). In species with well-developed elytral striae and cuticular microsculpture, both setae are generally present. In those species with very convex elytra, reduced elytral striation and smooth elytral cuticle, both setae are generally absent. The alternate states of apical seta absent/subapical present and apical seta present/subapical absent also occur. When the number of setae present varies within a species, with several state observed in more than ¼ of the individuals, the value is expressed as x1–x2. When one configuration is rare—observed in less than 10% of individuals, or only unilaterally—the rare value parenthetically follows the commonly observed value.

Figure 7.

Mecyclothorax aeneipennis, dorsal habitus view. Setal positions on the body from anterior to posterior: ms, mandibular scrobe seta; aso, anterior supraorbital seta; pso, posterior supraorbital seta; lp, lateral pronotal seta; bp; basal pronotal seta; psc, parascutellar seta; ale, anterior series of lateral elytral seta; ade, anterior dorsal elytral seta; pde, posterior dorsal elytral seta; ple, posterior series of lateral elytral setae; sae, subapical elytral seta; ae, apical elytral seta.

Full descriptions of all new species include sections describing the head, pronotum, prosternum, pterothoracic ventrites, abdomen, legs, microsculpture, coloration, male genitalia, and female reproductive tract. Several descriptive ratios are used. For the head these include the ocular ratio and ocular lobe ratio. The ocular ratio is defined as the maximal head width (MHW) across the convex surfaces of the compound eyes, divided by the minimal distance between the eyes across the frons (mFW). The ocular lobe ratio is measured as the length of the eye from anterior to posterior margin measured from dorsal aspect, divided by the distance from anterior eye margin to the posterior margin of the ocular lobe where its projected margin meets the gena. The first ratio provides a measure of eye convexity, whereas the ocular lobe ratio is related to eye diameter. Three descriptive ratios are used to help describe pronotal shape; 1, MPW/BPW, or maximum pronotal width divided by basal pronotal width; 2, MPW/PL, maximum pronotal width divided by pronotal length measured along the midline; and 3, APW/BPW, pronotal width across the front angles divided by basal pronotal width. Basal pronotal width is measured as the distance between the hind angles, whether or not the pronotal lateral margins converge anterad those angles. The degree of humeral development of the elytra varies greatly among these species, as all Hawaiian Mecyclothorax are brachypterous, and evolution has proceeded without the functional constraint necessitating maintenance of a fully functional flight apparatus. Thus elytra may be parallel sided and appearing much like those of mainland species that actively fly during their lifetime, or the elytra may be ovoid or ellipsoid with narrowed humeri. This disparity is measured by MEW/HuW, i.e. maximal elytral width divided by humeral width. The latter variable is measured as the transverse distance between the most anterior position of the basal elytral groove, generally where it meets the lateral marginal depression of the elytron. Occasionally two other ratios are used—MEW/MPW, or MEW/MHW—that is the maximal elytral width divided by the maximal pronotal width, or by the maximal head width across the convex surfaces of the compound eyes. These ratios may differentiate species when the degree of elytral “inflation” varies relative to the breadth of the forebody. Elytral setation and striation provide numerous useful characters. The parascutellar seta, present in the base of the sutural stria laterad the parascutellar striole (Fig. 7) may be present or absent, with these states invariant within species. The elytra bear a series of lateral setae associated with the 8th stria. These are arranged in an anterior series that commences just posterad the humeral angle, and a posterior series that lies along the margin of the elytral apical half anterad the subapical sinuation (Fig. 7). In some instances, a single isolated seta may lie between the anterior and posterior series. When available for viewing in dissected individuals, the configuration of the metathoracic flight wings is described. Venation of these variously reduced wing vestigia follows homologies proposed by Kukalová-Peck and Lawrence (1993).

Cuticular microsculpture is largely constant among specimens of the same species, though male specimens may exhibit less well-developed sculpticells compared to females, and they may have sculpticells that are slightly more transversely stretched than in females. The shapes of sculpticells and their aggregate patterns are described using the terminology of Lindroth (1974). When individual sculpticells are described, their length is the dimension along the head-abdomen body axis, and their breadth is the dimension perpendicular to that axis. As the pattern of microsculpture differs greatly on different portions of the major visible sclerites—head capsule, pronotum, elytra, various ventrites—diagnostic presentation of microsculpture specifies the exact position on the body at which it should be assessed.

The male aedeagal median lobe and internal sac offer substantial characters for species identification (Table 2). A specimen may be sexed as male by two means. Firstly, all males have the basal three protarsomeres bearing squamose adhesive setae medially on the ventral surface in addition to the trichiform subapical and apical setae laterally near the tarsomere apex. Moreover, in almost all Hawaiian Mecyclothorax species, the males have a single seta each side on the apical margin of the apical abdominal ventrite, whereas the females have two setae each side along the apical margin. In two exceptions, males have two setae each side—M. planipennis and M. planatus (Fig. 87A–B)—but in these species the females have four setae each side. In these rare exceptions to the setal count sex-determination rule, ventral setation of the protarsomere can be used to sex the specimen. When viewing the male aedeagal median lobe, diagnostic differences are often present in the configuration of the apex (Fig. 8), which may vary among the species in length, breadth, and curvature. The depth of the lobe—i.e. dorsoventral breadth—may also vary relative to the length of the aedeagus, with the lobe narrow (Fig. 45M, O) to very broad (Fig. 69). The internal sac bears a flagellar plate (terminology of Maddison 1993) that comprises ventrally a concave sclerotized, cuplike plate, and dorsally an overlying, lightly sclerotized membranous surface that bears the gonopore at its center (Fig. 8). Large spicules may be present on the sac surface, their aggregated structures called ostial microtrichial patches (Maddison 1993). When the patch lies along the midline of the sac between the lobe and the flagellar plate, it is termed the ventral ostial microtrichial patch. A patch may lie along the right side of the sac base, and extend toward the dorsal surface of the sac basad the gonopore. This is termed the dorsal ostial microtrichial patch. Usually the sac is a tubular structure (Fig. 8), although in some species it is divided, with a lobe that bears the flagellar plate—the apical lobe (Figs 120G, 150E–F, 161I)—complemented by a basal lobe situated dorsally closer to the dorsal surface of the median lobe.

Figure 8.

Male aedeagus, right view, Mecyclothorax aeneipennis: apex, apical portion of median lobe distad the ostial opening through which the internal sac everts; dop, dorsal ostial microtrichial patch of internal sac; fp, ventrally concave flagellar plate of internal sac; gp, gonopore positioned on membranous dorsal surface overlying flagellar plate; lp, left paramere; rp, right paramere; sac, internal sac; tip, most distal portion of apex; vop, ventral ostial microtrichial patch.

Abbreviations used in male genitalic and female reproductive tract species plates.

Abbreviation Structure
Males
al apical lobe of internal sac
bl basal lobe of internal sac
dop dorsal ostial microtrichial patch
fp flagellar plate
gp gonopore
ms macrospicules of internal sac
pal “pineapple” lobe of internal sac
vl ventral lobe of internal sac
vop ventral ostial microtrichial patch
Females
abc apical lobe of bursa copulatrix
bc bursa copulatrix
bsc bursal sclerite
co common oviduct
dgr defensive gland reservoir
hg hindgut
lo lateral oviduct
sg spermathecal gland
sgd spermathecal gland duct
sp spermatheca
v vagina

The female reproductive tract and associated gonocoxal ovipositors are interpreted (Table 2) following the system of Liebherr and Will (1998). The bursa copulatrix is a membranous sac of varying thickness and sclerotization, with the common oviduct entering on the ventral surface, and the spermathecal duct entering medially on the dorsal surface (Fig. 9A). The spermatheca is a fusiform structure of varying configuration, though annular rings are present to varying degrees. The spermatheca has an associated gland whose duct enters at the base of the spermathecal reservoir. The gland is exceedingly membranous and flaccid, with pore ductules visible over its surface. Gland size may vary among individuals of the same species. The underlying cause for this variation remains unstudied. The bursa copulatrix may be sclerotized on its ventral surface distad the juncture with the common oviduct (Fig. 54C). The gonocoxa is bipartite, with a lightly sclerotized basal gonocoxite 1, and a more distinctly sclerotized apical gonocoxite 2 (Fig. 9B). Medial to the base of the basal gonocoxite lies the ramus, a membranous fold of the ventral bursal wall mesad the gonocoxa. The paired rami may be narrowly sclerotized along their anterior margin (Fig. 9B). The basal gonocoxite usually bears a series of larger setae along the apical margin; apical fringe setae (Fig. 9B). These may vary from 1–6 each side, or there may be no setae at this position. The numbers of setae often vary bilaterally by one or two within the same specimen, reducing their utility for diagnosis. There are variable numbers of smaller setae along the medial surface of the basal gonocoxite, and a larger seta may be present at the apicomedial angle of the gonocoxite; the apicomedial seta. The more heavily sclerotized apical gonocoxite bears 1–2 lateral ensiform setae (rarely a third smaller seta), one dorsal ensiform seta, and two apical nematiform setae (Fig. 9B; terminology of Ball and Shpeley 1983). There are campaniform sensilla distributed over the surface of the apical gonocoxite. The presence and position of a series of these sensilla along the lateral margin distad the apical ensiform setae aids in determining how much of the gonocoxal apex has been worn off during ovipositional activity, that wearing down of the coxite especially prevalent in females of the species living in dry shrubland habitats (e.g. M. subconstrictus, Fig. 74D).

Figure 9.

Female reproductive tract structures, Mecyclothorax aeneipennis. A Female internal genitalia with associated gonocoxae, ventral view: bc, bursa copulatrix; co, common oviduct; gc, gonocoxa; sg, spermathecal gland; sp, spermatheca B Left gonocoxa, ventral view: afs, apical fringe setae; ans, apical nematiform setae; des, dorsal ensiform seta of apical gonocoxite; gc1, basal gonocoxite 1 of gonocoxa; gc2, apical gonocoxite 2 of gonocoxa; les, lateral ensiform setae of gonocoxite 2; r, ramus, a membranous or sclerotized lobe associated medially with base of gonocoxa (in this species, apical margin of ramus is narrowly sclerotized).

For previously described species, an initial diagnosis is followed by an identification section that provides additional characters that aid the determination. These include the descriptive ratios defined above, plus any other characters that might assist in the identification.

Hawaiian words, and formal place and animal names have been used as species epithets. Based on The Code (ICZN 1999), all glottal stops, macrons, or other accents must be excluded from words when they are used as formal scientific names. Similarly, in the current presentation of type data, such accents are excluded except when part of a collector’s name. Hawaiian words used in this revision outside of formal taxonomic procedures are presented in their Hawaiian form with included macrons, i.e. kahakō, and glottal stops, i.e. ‘okina. Pukui et al. (1974, 1975) served as reference sources for Hawaiian words and formal place names. Gagné and Cuddihy (1990) and Starr and Starr (2015) were consulted for Hawaiian native plant names.

Key to the species groups of Mecyclothorax Sharp from Haleakalā volcano, Maui, Hawai‘i

(based on the key to groups of Britton [1948b])

1 All elytral striae uniformly impressed, never fainter nor absent near apex; 7th stria always present and as distinctly impressed as other striae 2
1’ Outer elytral striae (except the 8th) less deeply impressed than those nearer suture, and usually fainter in apical half than towards base, often disappearing before reaching apex; one or more of the outer striae usually absent; 7th stria, when present, much less deeply impressed than 8th stria and striae on disc 5
2(1) Elytral third interval consistently with two or three dorsal elytral setae each side 3
2’ Elytral third interval with one dorsal elytral seta each side (infrequently unilaterally bisetose; examine more than one specimen if possible) M. constrictus group (001–003)
3(2) Larger, standardized body length including individuals > 3.9 mm (smaller specimens—3.6–3.9 mm—with irregularly fused elytral striae (Figs 44E, 52B) key to this couplet half) 4
3” Smaller, standardized body length < 3.9 mm (larger specimens—3.9–4.3 mm—with elytral intervals 6–9 contrastedly flavous relative to piceous intervals 1–5 (Figs 15, 20) key to this couplet half) M. obscuricornis group (004–015)
4(3) Elytral intervals slightly to moderately convex, striae minutely to distinctly punctate, greater strial punctation associated with more convex intervals; elytral striae regular, linear, adjacent striae united or approaching only where they fuse apically M. robustus group (016-026)
4’ Elytral intervals moderately to very convex, striae impunctate to minutely punctate, strial punctation and interval convexity not associated; striae may irregularly approach or anastomose on disc; this may involve fusion or approach of adjacent striae at dorsal elytral setae, or fusion or approach of striae 3 and 4, or 5 and 6 on elytral base M. interruptus group (027–035)
5(1) First and 2nd elytral striae subequally impressed at apex 6
5’ First elytral stria much more markedly impressed near apex than 2nd stria 9
6(5) Setiferous punctures of 3rd elytral interval set in small depressions that are never as wide as the interval 7
6’ Setiferous punctures of 3rd elytral interval set in obvious depressions that are as wide as or wider than interval M. sobrinus group (036–042)
7(6) Eyes relatively smaller and less convex; beetles either larger, standardized body length 4.7–6.2 mm, with small to moderate eyes, ocular ratio 1.29–1.53, OR smaller, standardized body length 3.2–4.5 mm, with little convex eyes, ocular ratio 1.28–1.39 8
7’ Eyes well developed, larger with outer surface distinctly convex, standardized body length 3.3–4.6 mm, eyes moderately to very convex, ocular ratio 1.41–1.61 M. ovipennis group (043–061)
8(7) Standardized body length > 4.50 mm; elytra with parascutellar seta and both subapical and apical setae present, setal formula 2 2 2 2 or 2 2 3–4 2 M. argutor group (062–069)
8’ Standardized body length < 4.50 mm; elytra without parascutellar, subapical, and apical setae; in some instances also bearing less than 2 dorsal elytral setae, setal formula 2 2 2 0, 2 2 1 0, or 2 2 0 0 M. microps group (070–075)
9(5) Second elytral stria as deeply impressed (or punctured) as sutural stria, at least in basal half; pronotal lateral marginal depression moderately narrow to broad, the margin upturned 10
9’ Second elytral stria less deeply impressed in basal half than sutural stria; pronotal lateral marginal depression very narrow, margin beadlike, especially so in species with evident second stria M. scaritoides group (076–084)
10(9) Elytral microsculpture slightly to distinctly transverse, especially at sides (if microsculpture reduced and cuticle glossy, assess sculpticell shape at elytral apex); elytra usually with distinct humeri; lateral margin of pronotum usually with a short sinuation anterad hind angle; elytra reddish to black, usually without metallic reflection 11
10’ Elytral microsculpture isodiametric, even at the sides (if microsculpture reduced and cuticle glossy, assess sculpticell shape at elytral apex); elytra obovoid to ellipsoid, humeri narrowly rounded; sides of the pronotum with an elongate sinuation anterad hind angle; elytra dark brown to black, with a metallic blue reflection M. haleakalae group (085–090)
11(10) Elytra dark brown to black, sometimes slightly aeneous, but without metallic green or blue reflection, surface often with distinct microsculpture; elytral intervals slightly to moderately convex, discal striae 1–3 to 1–6 well indicated, slightly to distinctly punctate; pronotal lateral margins moderately broad, the lateral margin upturned 12
11’. Elytra dark brown to black but with metallic green or blue reflection, surface highly polished, microsculpture reduced to absent; elytral intervals nearly flat, discal striae little impressed, at most striae 1–2 minutely punctate on disc; pronotal lateral marginal depression very narrow, margin little upturned M. vitreus group (091–096)
12(11) Pronotal lateral margins sinuate before hind angles outwards before basal margin distinct from lateral margins at angulate hind angle 13
12’ Pronotal lateral margins distinctly curved outwards before hind angles, posterior angles very obtuse, small and toothlike M. montivagus group (in part, 098–099)
13(12) Pronotal base narrow, MPW/BPW = 1.43–1.68; discal elytral striae moderately developed, intervals moderately convex to flat 14
13’ Pronotum broad basally with explanate hind angles, MPW/BPW = 1.20–1.27; discal elytral striae well developed, deep between the distinct punctures, elytral intervals of striae 2–4 convex basally M. montivagus group (in part, 097)
14(13) Elytra glossy, discal intervals without distinct microsculpture; elytra markedly convex, domed, lateral margins depressed relative to disc, lateral surfaces vertical adjoining lateral marginal depression M. ducalis group (100–105)
14’ Elytra bearing distinct microsculpture, from shallow transverse mesh on glossy elytral surface, to well-developed transverse mesh, sculpticell breadth 2–4× length; elytra moderately convex, lateral surfaces more gently sloped relative to disc, not vertically adjoining lateral margin depression M. palustris group (106–116)

Mecyclothorax constrictus species group

Diagnosis. Species in this group are characterized by deep elytral striae extended from the suture to the lateral margin with only stria 7 slightly shallower, and small to moderate body size (standardized body length 3.8–4.8 mm). Beetles of the Haleakalā species exhibit elytra bearing a single anterior dorsal elytral seta each side (rarely two setae or no seta present), and they lack both apical elytral setae. The pronotum is cordate, with MPW/BPW = 1.52–1.66, and the pronotal lateral margins are parallel or convergent anterad the right to slightly acute hind angles.

Membership and distribution. Other than the Haleakalā species, this group is represented by four species on Moloka‘i (Liebherr 2007). Beetles of the Moloka‘i species deviate from those on Haleakalā by the presence of 2–3 dorsal elytral setae, and one of the two apical elytral setae.

Key to adults of the Mecyclothorax constrictus species group, Haleakalā volcano, Maui, Hawai‘i

1 Basal portions of discal elytral intervals glossy, transverse sculpticells obsolete, not traceable at least near elytral basal groove, in some instances not visible in basal fifth of elytron; male aedeagal median lobe with short to moderately elongate apical extension (Fig. 11D–E, G, H) 2
1’ Basal portions of discal elytral intervals with distinct transverse-mesh microsculpture, the sculpticells evident even near elytral basal groove; male aedeagal median lobe with elongate, spatulate apical extension (Fig. 11A–B) (001) M. perseveratus sp. n.
2(1) Discal elytral striae 1–5 minutely punctate, the punctures longitudinal and not expanding breadth of striae (Fig. 10B); male aedeagal median lobe with parallel-sided apical extension (Fig. 11D–E, G) (002) M. perstriatus (Sharp)
2’ Discal elytral striae 1-5 more distinctly punctate, the punctures rounder and slightly expanding breadth of striae (Fig. 10C); male aedeagal median lobe with very short apex, the dorsal and ventral surfaces of extension convergent to tightly rounded tip (Fig. 11H) (003) M. superstriatus Liebherr

Mecyclothorax perseveratus sp. n.

Figs 10A, 11A–C, 12A, 13A, 14

Diagnosis

This is the largest bodied of the three Haleakalā species in this group (Fig. 10A); standardized body length 4.5–4.8 mm versus 3.5–4.6 mm for the other two species below. Dorsal microsculpture is more developed in this species, with the elytral disc covered with an elongate transverse mesh and parallel lines, and the pronotal disc bearing an evident transverse mesh. Setal formula 2 1 1(2) 0.

Figure 10.

Mecyclothorax constrictus group species, dorsal habitus view. A M. perseveratus (Waikamoi, 1160 m) B M. perstriatus (Kahakapao, 960 m) C M. superstriatus (Polipoli, 1730 m).

Description

(n = 3). Head capsule with frontal grooves straight, bordered by a lateral carina and mesal wrinkles; neck flat to slightly concave; eyes convex, largely covering ocular lobe, ocular ratio 1.52–1.55, ocular lobe ratio 0.89–0.94; labral anterior margin very shallowly emarginate; antennae filiform, antennomeres 2-3 covered with sparse pelage of small setae; mentum tooth narrow with acute sides, apex tightly rounded. Pronotum with lateral seta present, basal seta absent; MPW/BPW = 1.52–1.66; MPW/PL = 1.11–1.23; hind angle right to slightly acute; lateral margin convergent to subparallel anterad hind angle; median base with small punctures, sparse medially, denser laterally; basal margin broadly, slightly convex between laterobasal depressions; median longitudinal impression finely incised, shallow; anterior transverse impression distinct, slightly punctate in middle half; anterior callosity slightly convex, traversed by shallow wrinkles; front angles slightly protruded, tightly rounded; APW/BPW = 1.0–1.04; lateral marginal depression moderately narrow, flat near front angle, edge upturned; laterobasal depression a continuation of lateral depression, surface irregularly punctate. Proepisternum with 6 small punctures along hind marginal groove; prosternal process with narrow median impression, lateral margins a narrow bead anterad. Elytra broadly ovoid, convex, suture elevated relative to disc; basal groove nearly straight laterad scutellum, humeral angle subangulate, defined by a hitch at base of lateral depression; humeri broadly rounded, MEW/HuW = 2.11–2.14; elytra broad relative to pronotum and head, MEW/MPW = 1.50–1.59, MEW/MHW = 2.18–2.29; parascutellar seta present; parascutellar striole with 2–4 punctures, striole shallow between punctures; juncture of sutural intervals each side upraised, producing a median callus; depth of sutural or first stria subequal to 2nd stria from base to apex; discal stria finely punctate basally, narrow and smooth apically; lateral striae punctate basally, the punctures small, slightly expanding striae in basal half, punctures absent apically; intervals 2–7 moderately convex; all striae finely incised apically; 8th interval laterad 7th stria not more convex apically than other intervals; either 1 or 2 dorsal elytral setae, if two, then setae at 0.10× and 0.28–0.33× elytral length, if one seta, then situated 0.24–0.30× elytral length; apical and subapical setae absent; lateral elytral setae arranged as 7 + 6 (anterior and posterior series); elytral marginal depression narrow, lateral margin upturned; subapical sinuation broadly excavated, shallow, internal plica visible from dorsal view. Mesepisternum punctate, ~13 punctures in 2–3 vertical rows; metepisternal medial length/maximum width = 1.39; metepisternum/metepimeron suture distinct. Abdomen with irregular longitudinal wrinkles on ventrites 1–4, suture between ventrites 2 and 3 complete; males with 2 apical abdominal setae, females with 4 equally spaced setae plus 4 short setae arranged in a median trapezoid. Legs-metatarsomere 1/metatibial length ratio = 0.195; metatarsomere 4 lobe length 1.5× medial tarsomere length, subapical and apical setae present; metatarsal dorsolateral sulci very narrow, shallow, evident on mt1 and mt2 only. Microsculpture of head capsule transverse, vertex with transverse mesh and fine wrinkles; pronotal disc with evident, reflective transverse-mesh microsculpture; pronotal median base with reflective isodiametric mesh in transverse rows; elytral disc with elongate transverse mesh and parallel lines, apex with evident transverse mesh; metasternum covered with transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse sculpticells. Coloration of vertex brunneous with a slight piceous cast; antennomeres 1–3 flavous, 4–11 rufobrunneous; pronotal disc rufobrunneous, pronotal margins slightly, broadly paler; proepipleuron rufoflavous, proepisternum brunneous with piceous cast; elytral disc rufobrunneous, darkest behind middle, sutural interval paler, rufous basally, flavous apically; elytral margins concolorous with disc basally, broadly paler apically; elytral apex broadly flavous, flavous coloration extended anterad along suture; elytral epipleuron rufoflavous, metepisternum brunneous; abdominal ventrites 1–3 brunneous medially, more apical ventrites flavous; metafemur flavous, metatibia flavous with brunneous cast.

Male genitalia (n = 1). Aedeagal median lobe gracile, elongate, distance from parameral articulation to tip 4.7× depth at midlength (Fig. 11A); median lobe apex parallel sided with rounded tip, apex evenly downcurved distad ostial opening in lateral view (Fig. 11A–B), apex curved to right with top expanded as a knob in ventral view (Fig. 11C); internal sac elongate, flagellar plate small, sac covered with fine spicules only.

Figure 11.

Male aedeagus, M. constrictus group species (for abbreviations see Table 2, p. 23). A–C M. perseveratus, right, left, and ventral views, sac everted (Waikamoi 1160 m) D–G M. perstriatus D Right view (Waikamoi, 1534-1660 m) E Right view (Kahakapao, 960 m) F Ventral view (Kahakapao, 960 m) G Right view (Waikamoi, 1300 m) H–I M. superstriatus, right and ventral views (Polipoli, 1730 m).

Female reproductive tract (n = 1). Bursa copulatrix columnar, base broad at vagina, narrower at midlength, bursal length 0.80 mm, breadth 0.40 mm at base (Fig. 12A); bursal surface translucent, wrinkled, not sclerotized; gonocoxite 1 with 2–3 apical fringe setae, 1 small seta at apicomedial angle, 4–5 setae along medial surface (Fig. 13A); gonocoxite 2 subacuminate with lateral panhandle extension; 2 moderately elongate lateral ensiform setae, 0.36× length of gonocoxite; apical nematiform setae on medial surface at 0.80× gonocoxite length.

Figure 12.

Female bursa copulatrix and associated reproductive structures, M. constrictus group species, ventral view (for abbreviations see Table 2, p. 23). A M. perseveratus (Waikamoi, 1160 m) B M. perstriatus (Kīpahulu, 1800 m) C M. perstriatus (Kuhiwa, 1600 m) D M. superstriatus (Polipoli, 1730 m). Scale bar = 0.50 mm.

Figure 13.

Left female gonocoxa, M. constrictus group species, ventral view. A M. perseveratus (Waikamoi, 1160 m) B M. perstriatus (Kuhiwa, 1600 m) C M. superstriatus (Polipoli, 1730 m).

Holotype

Male (CUIC) labeled: HI: Maui Haleakala Kula / Pipeline Rd. W Waikamoi / Gulch 15-V-1998 lot04 / 1160 m el. pyr. fog mossy / ohia/ logs J.K. Liebherr // HOLOTYPE / Mecyclothorax / perseveratus / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes

HI: Maui: Koolau For. Res., Kula Pipeline Rd., pyrethrin fog Metrosideros/moss, 1160 m el., 15-v-1998 lot 06, Polhemus (NMNH, 1), wet forest, yellow pan trap, 1183–1280 m el., vi-viii-2006, Leblanc (CUIC, 1; UHIM, 1), Makawao Flume Rd., ecotone forest, yellow pan trap, 1293 m el., vi-viii-2006, Leblanc (CUIC, 1; UHIM, 2), Waikamoi flume tanks [labeled Waikamoi N.C.P.], 1275 m el., 30-v-1993, Tauber/Tauber (CUIC, 1).

Etymology

The adjectival species epithet perseveratus is based on the verb perseverate; to repeat insistently or redundantly. Such a name could be appropriately applied for any number of Hawaiian Mecyclothorax, but it is used here as the name shares the first syllable with the following cryptic sibling species.

Distribution and habitat

M. perseveratus is known to occur only in the Waikamoi drainage from 1160–1300 m elevation (Fig. 14). As such, the species is sympatric with lower elevational populations of M. perstriatus. Individuals have been collected from the trunks of moss-covered ‘ōhi‘a trees, as well as from mossy downed logs of the same species. The beetles must actively walk across the forest floor, as they have been collected from fluid-filled yellow-pan traps.

Figure 14.

Recorded geographic distributions of M. constrictus group species.

Mecyclothorax perstriatus (Sharp)

Figs 10B, 11D–G, 12B–C, 13B, 14

Thriscothorax perstriatus Sharp 1903: 260.

Mecyclothorax perstriatus, Britton 1948b: 158; Liebherr 2005b: 122.

Oopterus plicaticollis Boisduval, Karsch 1881: 1 (misidentification).

Thriscothorax modestus Sharp, Swezey 1954: 53 (misidentification, Cibotium associate).

Diagnosis

Individuals of M. perstriatus and M. superstriatus share reduced microsculpture, the pronotal disc glossy with an obsolete transverse mesh visible over portions of the disc (Fig. 10B–C). However the elytral microsculpture is more developed in this species, being an evident, shallow transverse mesh versus an obsolete transverse mesh on a glossy surface in M. superstriatus. Beetles of both species also have smaller eyes that cover less of the ocular lobe than do those of M. perseveratus, with M. perstriatus exhibiting an ocular lobe ratio = 0.83–0.86. The male genitalia provide certain diagnosis, with the aedeagal median lobe apex of M. perstriatus males extended and downturned (Fig. 11D–G), versus very short and not at all downturned in M. superstriatus (Fig. 11H–I). Setal formula 2 1(2) 1 0; only one individual was observed within which the basal pronotal seta was unilaterally present. Standardized body length 3.5–4.6 mm.

Identification

(n = 5). The full description of M. perseveratus serves to describe this species with the exception of characters mentioned in the diagnosis. The eyes are convex; ocular ratio 1.51–1.55. The pronotum is cordate with right to acute hind angles; MPW/BPW = 1.54–1.65. The elytra are narrowly to more broadly ovoid; MEW/HuW = 2.09–2.23.

Male genitalia (n = 20). Aedeagal median lobe gracile but shorter than that of M. perseveratus males, distance from parameral articulation to tip 3.5–4.3× medial breadth (Fig. 11D–E, G); median lobe apex shorter than that of M. perseveratus, ventral margin angulate just distad ostial opening in lateral view; median lobe apex moderately curved to the right with tip slightly expanded in ventral view (Fig. 11F); internal sac with evident, short flagellar plate, but without evident microtrichial patches (uneverted specimens).

Female reproductive tract (n = 2). Bursa copulatrix bipartite, apex digitiform and narrower than base at vagina, bursa 0.46 mm long overall, base at vagina 0.42 mm broad, digitiform apical lobe 0.37 mm long, 0.14 mm broad (Fig. 12B–C); bursal surface membranous, translucent, finely wrinkled; gonocoxite 1 with 3 apical fringe setae, a moderate apicomedial seta at apex of medial surface, 5–6 setae basally on medial surface (Fig. 13B); gonocoxite 2 subacuminate with lateral extension, 2 gracile lateral ensiform setae, apical nematiform setae on medial surface at 0.75× gonocoxite length.

Lectotype

Female (BMNH), designated by Liebherr (2005b: 122).

Misidentifications

Karsch (1881) lists Oopterus plicaticollis Boisduval, with its collecting information recorded under MNHU lot number 60815 as “Olinda, 1, Dr. O. Finsch.” The single specimen is M. perstriatus, and so Karsch’s mention of the species represents a misidentification. Documentation of Swezey’s (1954) misidentification of M. perstriatus as M. modestus is supported by: 1, specimens that match his collecting date and host information that are; 2, not attributable to M. cordaticollis, the senior name synonymous below with M. modestus, but instead represent this species.

Distribution and habitat

The recorded distribution of this species spans the western Waikamoi forests, the Hāna Bogs, upper Kīpahulu Valley, and the Manawainui Planeze (Fig. 14). It is a wet forest species, and has been found in association with ‘ōhi‘a, koa, or ‘ōlapa trees, or various ferns; Asplenium, Athyrium (‘akolea), Cibotium (hāpu‘u), or Sadleria (‘ama‘u). The beetles are active on vegetation at night, and also may be found by sifting litter. As with M. perseveratus, beetles have been collected from yellow-pan traps set on the ground, implying they active walk over the forest floor.

Mecyclothorax superstriatus Liebherr

Figs 10C, 11H–I, 12D, 13C, 14

Mecyclothorax superstriatus Liebherr 2005b: 118.

Diagnosis

Superficially similar to the preceding two species, but individuals tend to be smaller—standardized body length 3.8–4.2 mm—with less developed microsculpture (Fig. 10C). The pronotal disc and discal elytral intervals are glossy, with only a very shallow transverse mesh discernible over portions of the cuticle. The male aedeagus is small (Figs 11H–I) with non-projected apex. Setal formula 2 1 1(0) 0; of 13 individuals assessed, 9 have the anterior dorsal elytral seta present both sides, 3 have the seta present unilaterally, and 1 lacks any dorsal elytral setae.

Identification

(n = 5). As M. perstriatus above, this species shares most characters with M. perseveratus. The eyes are convex, ocular ratio = 1.46–1.55, covering the ocular lobe as in M. perstriatus; ocular lobe ratio = 0.81–0.87. Being of smaller body size, the pronotum appears more constricted basally, though the MPW/BPW ratio range of 1.53–1.63 overlaps the values of the other two species. Elytral shape is also variable as in the other two species; MEW/HuW = 2.05–2.23.

Male genitalia (n = 1). Aedeagal median lobe short, apex barely extended beyond ostial opening, shaft thin, distance from parameral articulation to tip 5.7× depth at midlength (Fig. 11H); median lobe apex slightly curved to the right, tip not expanded in ventral view (Fig. 11I); internal sac with evident flagellar plate, but without other ornamentation.

Female reproductive tract (n = 1). Bursa copulatrix bipartite, apex digitiform and narrower than base at vagina, bursa 0.40 mm long overall, base at vagina 0.26 mm broad, digitiform apical lobe 0.17 mm long, 0.13 mm broad (Fig. 12D); bursal surface membranous, translucent, finely wrinkled; gonocoxite 1 with 3 apical fringe setae, a thin apicomedial seta at apex of medial surface, 4–5 setae more basally on medial surface (Fig. 13C); gonocoxite 2 subacuminate with lateral extension, 2 gracile lateral ensiform setae, apical nematiform setae on medial surface at 0.75× gonocoxite length.

Holotype

Male (NMNH) dissected (Liebherr 2005b: 121). Type locality HI: Maui, Haleakalā, Polipoli S.R.A., 1770 m el.

Distribution and habitat

M. superstriatus is restricted to the Polipoli Springs area along the southwest rift of Haleakalā (Fig. 14). They have been found from 1730–1770 m elevation, either in a deep ravine on a moist rock face that was covered with ferns and mosses, or in moss on a moist Pinus radiata log on a ravine floor. Both situations were among the moister microhabitats in the immediate area.

Mecyclothorax obscuricornis species group

Diagnosis. Species of this group are characterized by small body size (standardized body length 3.2–4.3 mm), and elytral striae that are deep and equally well-developed from suture to lateral margin. The pronotum is moderately constricted basally, with MPW/BPW = 1.38–1.61. Both anterior and posterior dorsal elytral setae are present. The Haleakalā species exhibit two different coloration patterns: 1, pale pronotal and elytral margins contrasted with piceous discs (Figs 15, 20A); 2, more uniform coloration with margins concolorous to slightly paler (Figs 20B–D, 24).

Membership and distribution. This species group is restricted to three of the volcanoes comprising the former Maui Nui; East Moloka‘i with three species (Liebherr 2007), West Maui with four species (Liebherr 2011), and Haleakalā with the 12 species treated below.

Key to adults of the Mecyclothorax obscuricornis species group, Haleakalā volcano, Maui, Hawai‘i

1 Elytral intervals 2–5 dark, piceous, and contrasted with rufous sutural interval and pale, testaceous intervals 7–9 (Figs 15, 20A) 2
1’ Elytral intervals concolorous, or sutural and lateral intervals only slightly paler than discal striae 2–5 (Figs 20B–D, 24) 6
2(1) Pronotal disc smooth medially, the median longitudinal impression adjoined by at most shallow wrinkles (Figs 15B–D, 20A) 3
2’ Pronotal disc covered with rugose transverse wrinkles, pronotal surface adjacent to the median longitudinal impression irregular (Fig. 15A) (004) M. daptinus Sharp
3(2) Pronotal base moderately broad, MPW/BPW = 1.42–1.53, pronotal lateral margins briefly subparallel or divergent anterad hind angles 4
3’ Pronotum constricted basally, MPW/BPW = 1.57–1.61, pronotal lateral margins subparallel to slightly convergent anterad hind angles (005) M. notobscuricornis sp. n.
4(3) Pronotal hind angles distinct, lateral margins subparallel to sinuate before angles; pronotal disc pearlaceous due to distinct transverse-mesh microsculpture, sculpticell breadth 2× length 5
4’ Pronotal hind angles indistinct, subangulate, lateral margins divergent anterad angles; pronotal disc glossy, covered with shallow transverse-mesh microsculpture, sculpticell breadth 3× length (006) M. mordax sp. n.
5(4) Eyes moderate, ocular lobe ratio = 0.75–0.77, outer surface more convex, ocular ratio = 1.44–1.55; elytra subquadrate, humeri broader relative to maximum breadth, MEW/HuW = 1.81–1.86 (Fig. 15D) (007) M. mordicus sp. n.
5’ Eyes smaller, ocular lobe ratio = 0.71–0.74, outer surface less convex, ocular ratio = 1.40–1.43; elytra subovoid, humeri narrower relative to broadly rounded margin behind, MEW/HuW =1.98–2.03 (Fig. 20A) (008) M. manducus sp. n.
6(1) Body moderately broad, eyes convex or not, MEW/MHW = 1.95–2.13 (largest values in species with less convex eyes); pronotum and elytra with margins narrowly paler, femora contrastedly paler, rufoflavous (Figs 20C–D, 24) 7
6’ Body broad, robust, eyes convex, MEW/MHW = 2.15; head, pronotum and elytra dark, fuscous, legs hardly paler (Fig. 20B) (009) M. ambulatus sp. n.
7(6) Pronotum bisetose, the lateral setae present and basal setae absent, elytral lateral margins convex near midlength, the elytra variously orbicular (Figs 20D, 24); pronotal base with distinct punctures, which may be accompanied by rugose wrinkles 8
7’ Pronotum quadrisetose, both lateral and basal setae present, elytral lateral margins straight, though divergent, near elytral midlength (Fig. 20C); pronotal base slightly rugose but without distinct punctures (010) M. montanus sp. n.
8(7) Vertex with well-developed microsculpture, either isodiametric or transverse mesh mixed with isodiametric sculpticells 9
8’ Vertex glossy, with obsolete transverse-mesh microsculpture visible only over portions of surface 10
9(8) Discal elytral striae smooth, intervals broadly convex; elytra orbicular, lateral margins broadly convex (Fig. 20D) (011) M. obscuricolor (Blackburn)
9’ Discal elytral striae punctate, the associated elytral intervals moderately convex; elytra elongate, the lateral margins moderately convex (Fig. 24A) (012) M. obscuricornis Sharp
10(8) Discal elytral striae 1–6 moderately punctate, punctures evident but not deep, little expanding strial breadth (Fig. 24C–D); eyes more convex, ocular ratio = 1.43–1.51, larger in diameter, ocular lobe ratio = 0.79–0.86 11
10’ Discal elytral striae 1–6 distinctly punctate, punctures deep, expanding strial breadth (Fig. 24B); eyes less convex, ocular ratio = 1.38–1.47, smaller in diameter, ocular lobe ratio = 0.79–0.81 (013) M. waikamoi sp. n.
11(10) Pronotal hind angles protruded, lateral margins straight for short distance anterad angles (Fig. 24C); male aedeagal median lobe with parallel-sided apex, terminated ventrally as a narrowly rounded tip (Fig. 26B–D) (014) M. poouli sp. n.
11’ Pronotal hind angles less protruded, lateral margins divergent immediately anterad angles (Fig. 24D); male aedeagal median lobe with very short, broad apex terminated ventrally as a subangulate tip (Fig. 26E) (015) M. ahulili sp. n.

Mecyclothorax daptinus Sharp

Figs 15A, 16A–B, 17A, 18A, 19

Mecyclothorax daptinus Sharp 1903: 249; Britton 1948b: 160.

Diagnosis

This species is easily diagnosed by the pale pronotal and elytral margins contrasted with piceous discal areas and the rugose transverse wrinkles of the pronotal disc (Fig. 15A). The pronotum is moderately constricted basally–MPW/BPW = 1.44–1.59–and the forebody dorsal surface bears well-developed microsculpture. The vertex is covered with upraised isodiametric sculpticells in transverse rows, and the pronotal disc is covered with a transverse mesh, sculpticell breadth 2–3× length. Conversely, the elytral discal intervals are glossy, with a transverse mesh to transverse lines toward the lateral elytral margins. Setal formula 2 (1-2) 2 1[sae]; of the five individuals scored, two have both lateral and basal pronotal setae, and three have only the lateral pair of setae. Standardized body length 3.4–4.1 mm.

Figure 15.

Mecyclothorax obscuricornis group species, dorsal habitus view. A M. daptinus (Ukulele Camp Pipeline, 1510 m) B M. notobscuricornis (Honomanu, 1700 m) C M. mordax (ESE Kuiki, 2164 m) D M. mordicus (Kuhiwa, 1780 m).

Identification

(n = 5). Beetles of this species are of stocky stature, with short, submoniliform antennal segments and short legs. The eyes are moderately convex, ocular ratio = 1.44–1.52, but they cover only the anterior portion of the protruded ocular lobes; ocular lobe ratio = 0.72–0.80. In addition to the transverse wrinkles on the pronotal disc, the deep anterior transverse impression and elevated and flat anterior callosity are crossed by dense longitudinal wrinkles. The elytra are subquadrate with tightly rounded humeral angles—MEW/HuW = 1.89–1.92—and the discal elytral intervals are convex, the associated striae 2–3 minutely punctate basally, striae 4–8 with only minute irregularities.

Male genitalia (n = 2). Aedeagal median lobe robust, short, distance from parameral articulation 2.8× depth at midlength, apex briefly extended and evenly downturned beyond ostial opening (Fig. 16A); median lobe not curved to the right, though left side more broadly curved to rounded tip in ventral view (Fig. 16B); a moderate sized flagellar plate visible in uneverted specimen (Fig. 16B), no other sac ornamentation evident.

Figure 16.

Male aedeagus, M. obscuricornis group species (for abbreviations see Table 2, p. 23). A–B M. daptinus, right and ventral views (Ukulele Camp, 1525 m) C–D M. notobscuricornis, right and ventral views (Honomanu, 1700 m) E–F M. mordax, right and ventral views (ESE Kuiki, 2164 m) G–H M. mordicus, right and ventral views (Kuhiwa, 1780 m) I–J M. manducus, right and left views (Kīpahulu, 915 m) K–L M. ambulatus, right and ventral views (Haleakalā, 1500 ft., RCLP).

Female reproductive tract (n = 1). Bursa copulatrix basally broad, apically digitiform, overall length 0.43 mm, basal breadth 0.30 mm, apical lobe breadth 0.11 mm (Fig. 17A); bursal walls membranous, thin, transparent; gonocoxite 1 with 2 apical fringe setae, medial seta smaller, 1–2 small setae on medial surface (Fig. 18A); gonocoxite 2 subtriangular, apex subacuminate, base evenly extended from curved lateral surface, with 2 lateral ensiform setae, apical seta broader and longer, apical nematiform setae on medioventral surface at 0.71× gonocoxite length.

Figure 17.

Female bursa copulatrix and associated reproductive structures, M. obscuricornis group species, ventral view (for abbreviations see Table 2, p. 23). A M. daptinus (Ukulele Camp, 1525 m) B M. notobscuricornis (Haipua‘ena, 455 m) C M. manducus (Kīpahulu, 910 m) D M. montanus (ESE Kuiki, 2145 m). Scale bar = 0.50 mm.

Figure 18.

Left female gonocoxa, M. obscuricornis group species, ventral view. A M. daptinus (Ukulele Camp, 1525 m) B M. notobscuricornis (Haipua‘ena, 455 m) C M. manducus (Kīpahulu, 910 m) D M. montanus (ESE Kuiki, 2145 m) E M. obscuricolor (Ukulele Camp, 1525-1960 m) F M. obscuricornis (Ukulele Camp, 1525 m).

Lectotype

Female (BMNH) hereby designated, labeled: Mecyclothorax daptinus Type D.S. Haleakala Perkins 113 (on mounting platen) // Type // Hawaiian Is. Perkins 1904-336 // Haleakala Maui 5000 ft. Perkins IV 1894 // LECTOTYPE Mecyclothorax daptinus Sharp J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat

M. daptinus is distributed along the leeward edge of the Waikamoi forest (Fig. 19), with the only recent records resulting from the application of pyrethrin fog to a mossy koa trunk or a mossy ‘ōhi‘a log. All but one of the collections have come from mesic forest near the Ukulele Camp site—~1500 m elevation—with the exception being a site on the Kula Pipeline Road at 1300 m elevation.

Figure 19.

Recorded geographic distributions of M. obscuricornis group species.

Mecyclothorax notobscuricornis sp. n.

Figs 15B, 16C–D, 17B, 18B, 19

Diagnosis

Among the pale-margined members of this species group, M. notobscuricornis (Fig. 15B) stands out due to the basally constricted pronotum; MPW/BPW = 1.57–1.61. This is also the largest-bodied species in the group, with standardized body length 3.6–4.3 mm. Like M. daptinus, this species is characterized by well-developed forebody microsculpture and glossy elytra. The vertex is covered with well-developed isodiametric and transverse-mesh microsculpture, the pronotal disc by a well-developed transverse mesh, sculpticell breadth 2–3× length, whereas the discal elytral intervals are glossy, their surface covered with reduced transverse lines. Setal formula 2 1 2 1[sae].

Description

(n = 4). Head capsule with frontal grooves broad near clypeus, an associated lateral carina extended to anterior supraorbital seta; dorsal impression of neck flat to slightly concave; labral anterior margin broadly, shallowly emarginate; antennomeres 2-3 with sparse pelage of short setae; mentum tooth with sides acute, apex tightly rounded. Pronotum with lateral setae present, basal absent; hind angle obtuse to right, to slightly acute, margin rounded posterad angle; lateral margin subparallel to convergent anterad hind angle; median base depressed relative to disc, with fine longitudinal wrinkles; basal margin straight medially, expanded posterad laterobasal depressions; median longitudinal impression moderately deep at midlength, finely incised, extended onto median base; anterior transverse impression broad, shallow, crossed with longitudinal wrinkles, lined with granulate isodiametric microsculpture; anterior callosity slightly convex; front angles slightly projected, tightly rounded, more distant than hind angles, APW/BPW = 1.06–1.12; lateral marginal depression narrow throughout length, edge reflexed, beadlike margin only anterad and posterad hind angle; laterobasal depression smooth, continuous with lateral depression. Proepisternum with smooth hind marginal groove; prosternal process medially depressed, sides broadly upraised laterally. Elytra subovoid, disc moderately convex, lateral margins more so; basal groove distinctly recurved to subangulate humeral angle, MEW/HuW = 1.95–2.07; parascutellar seta present; parascutellar striole with 3–5 punctures, deep, continuous; sutural interval more convex than lateral intervals, sutural juncture elevated; sutural and 2nd striae of subequal depth from base to apex; all striae deep, associated intervals convex; 7th and 8th interval similarly convex near apex; 2 dorsal elytral setae, anterior at 0.29×, and posterior at 0.58–0.61× elytral length, setae situated in depressions spanning 2/3 of interval 3; subapical seta present, apical seta absent; lateral elytral setae arranged in anterior series of 7 setae, posterior series of 5(6) setae; elytral marginal depression broadly reflexed, translucent posterad humerus, narrowed apically to beadlike margin anterad subapical sinuation; subapical sinuation shallow, more abruptly incurved anteriorly. Mesepisternum with 6 shallow punctures, most in 1 row; metepisternal width to length ratio = 0.82; metepisternum/metepimeron suture distinct. Abdomen with irregular wrinkles laterally on ventrites 1–5; suture between ventrites 2 and 3 reduced, effaced laterally; apical male ventrite with 2 apical setae, apical female ventrite with 4 equally spaced setae plus a median trapezoid of 4 small setae. Legs-metatarsomere 1/metatibial length ratio = 0.19; metatarsomere 4 length along outer lobe 1.25× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci narrow, lateral, median area broad. Microsculpture of vertex well-developed isodiametric mesh in rows; pronotal disc with well-developed transverse mesh, sculpticell breadth 2–3× length; pronotal median base with upraised isodiametric and transverse mesh, transverse sculpticell breadth 2× length; elytral discal surface glossy, with reduced transverse lines; elytral apex with shallow transverse mesh and lines; metasternum with distinct transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous; antennomere 1 flavous, antennomeres 2–3 rufous, 4–11 rufobrunneous; pronotal disc rufopiceous, lateral margins flavous, apex and base rufoflavous; proepipleuron rufoflavous, proepisternum rufobrunneous; elytral disc rufopiceous on intervals 2–5 to 2–6, base of interval 6 flavous; sutural interval rufobrunneous basally, rufoflavous apically; elytral intervals 7–9 pale, flavous, apex flavous to apical juncture of intervals 3 and 4; elytral epipleuron flavous dorsally, rufoflavous ventrally, metepisternum rufopiceous; abdominal ventrites 1–5 rufopiceous medially, 3–6 flavous laterally; apical half of apical ventrite 6 pale, flavous; metafemur flavous; metatibia rufoflavous with piceous cast.

Male genitalia (n = 1). Aedeagal median lobe broad, robust, distance from parameral articulation to tip 2.5× depth at midlength, apex broadly rounded and little extended beyond ostial opening (Fig. 16C); slightly curved to the right, the tip broadly rounded in ventral view (Fig. 16D); internal sac unornamented, large flagellar plate evident inside dorsal surface of median lobe dorsad parameral articulation (Fig. 11C).

Female reproductive tract (n = 1). Bursa copulatrix elongate, broad with rounded apex, length 0.57 mm, breadth at bursal-vaginal juncture 0.23 mm, maximum vagina breadth 0.35 mm (Fig. 17B); bursal walls translucent, thinly wrinkled; gonocoxite 1 with 3 apical fringe setae, 5 setae on medial surface (Fig. 18B); gonocoxite 2 subtriangular, apex tightly rounded, base with short broad lateral extension, 2 lateral ensiform setae, the apical seta broader and longer, apical nematiform setae on medioventral surface at 0.70× gonocoxite length.

Holotype

Male (CUIC) dissected and labeled: HI: Maui Haleakala NW / slope Waikamoi Pres. / trans. 3 @ 1700 m el. / 10-V-1991 sifting / litter J.K. Liebherr // 2 // Mecyclothorax / notobscuricornis / ♂ #5 / det. J.K. Liebherr 2014 // HOLOTYPE / Mecyclothorax / notobscuricornis / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Allotype

Female (CUIC) labeled: HI: Maui Haleakala NW / slope Waikamoi Pres. / trans. 3 @ 1700 m el. / 8-V-1991 scraping / ohia w/ moss & dirt // J.K. Liebherr / collector // Mecyclothorax / notobscuricornis / ♀ photo / det. J.K. Liebherr 2014 // ALLOTYPE / Mecyclothorax / notobscuricornis / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes

Koolau F.R., Haipuaena, 455 m el., 30-vi-1920, Bryan (BPBM, 2).

Etymology

The adjectival species epithet notobscuricornis is drawn from the converse name obscuricornis, another species in this group. Why Sharp (1903) used that name is unknown, though it too can be derived from the name of a previously described and related species; M. obscuricolor (Blackburn).

Distribution and habitat

M. notobscuricornis (Fig. 19) is known from one recent collecting site, the upper Honomanu drainage at 1700 m elevation, and one historical 1920 collecting site near Haipua‘ena Camp along the Koolau Ditch (Wilcox 1996), 425 m elevation (BPBM, E.H. Bryan, Jr.). Recent records were from sifted leaf litter and from moss and associated humus on the trunk of a large ‘ōhi‘a tree.

Mecyclothorax mordax sp. n.

Figs 15C, 16E–F, 19

Diagnosis

Among the pale-margined species in this group, this species can be diagnosed by the obtuse, rounded pronotal hind angles, the lateral margins only slightly sinuate anterad the hind angles (Fig. 15C). The elytra are subquadrate, with the lateral margins broadly extended posterad the rounded humeri. The pronotal base is smooth, with the median base moderately depressed and sparsely covered with shallow punctures and longitudinal wrinkles. Setal formula 2120. Standardized body length 3.8 mm.

Description

(n = 1). Head capsule with frontal grooves broad at clypeus, a lateral carina present to anterior supraorbital seta; dorsal impression of neck flat to slightly concave; eyes little convex, ocular ratio = 1.37, ocular lobe ratio = 0.77; labral anterior margin with broad, shallow emargination; antennae filiform, antennomere 2 sparsely setose, antennomere 3 with well-developed pelage of short setae; mentum tooth with sides acute, apex rounded. Pronotum with lateral seta present, basal seta absent; pronotal base little constricted, MPW/BPW = 1.42; basal margin straight medially, expanded posterad laterobasal depressions; median longitudinal impression shallow, finely incised; anterior transverse impression deep, narrow, finely incised; anterior callosity slightly convex, glossy but crossed by indistinct wrinkles; front angles moderately projected, tightly rounded; apical and basal angles at subequal separation, APW/BPW = 0.99; lateral marginal depression narrow but edge reflexed anteriorly, broader at midlength, beaded at hind angle; laterobasal depression smooth, concave, continuous with lateral depression. Proepisternum with 5 minute punctures along hind marginal groove; prosternal process medially depressed, broadly upraised laterally. Elytra subquadrate, disc moderately convex, sides slightly more sloped; basal groove moderately recurved to meet rounded humeral angle; parascutellar seta present; parascutellar striole with 3–5 punctures, striole shallow between punctures; sutural interval more convex than lateral intervals, sutural juncture elevated; sutural and 2nd striae of subequal depth from base to apex; striae 1–4 distinctly punctate basally, the punctures expanding strial breadth; intervals 2–8 convex to apex; 7th and 8th interval similarly convex mesad subapical sinuation; 2 dorsal elytral setae at 0.29× and 0.59× elytral length, setal impressions spanning 3rd interval; apical and subapical setae absent; lateral elytral setae arranged as anterior series of 7 setae, and posterior series of 5–6 setae; elytral marginal depression narrow at humerus, posteriorly expanded laterally, broad to midlength, a narrow bead at subapical sinuation; subapical sinuation very shallow, nearly obsolete. Mesepisternum with ~8 shallow punctures arranged in 2–3 rows; metepisternal width to length ratio = 0.80; metepisternum/metepimeron suture distinct; metathoracic flight wing extended to posterior margin of metanotum. Abdomen with irregular lateral wrinkles on ventrites 1–4; suture between ventrites 2 and 3 complete; apical ventrite of male with 2 apical setae. Legs-metatarsomere 1/metatibial length ratio = 0.19; metatarsomere 4 length along outer lobe 1.33× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci narrow, lateral, median area broad. Microsculpture of vertex shallow transverse mesh, sculpticell breadth 2× length; pronotal disc with shallow transverse mesh, sculpticell breadth 2× length; pronotal median base with shallow isodiametric and transverse-mesh microsculpture; elytral disc with shallow transverse mesh, sculpticell breadth 2× length; elytral apex with shallow transverse mesh, sculpticell breadth 2–3× length, plus transverse lines; metasternum with distinct transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex a glossy rufopiceous, antennomere 1 rufoflavous, antennomeres 2–3 rufoflavous, 4–11 rufobrunneous; pronotal disc rufopiceous, pronotal anterior callosity, lateral margins, and median base rufoflavous; proepipleuron flavous, proepisternum rufobrunneous with piceous cast; elytral disc with intervals 2–5 piceous from base to near apex, interval 6 rufous, and 7–9 flavous continuous with broadly flavous apex; sutural interval rufoflavous basally, flavous in apical 1/3; elytral epipleuron pale creamy ivory, metepisternum rufopiceous with piceous cast; abdominal ventrites 1–3 medially, and 4–6 mediobasally piceous, flavous laterally and apically; apical 2/3 of apical abdominal ventrite 6 flavous; metafemur flavous with piceous cloud covering basal half of anterior face; metatibia rufoflavous with brunneous cast.

Male genitalia (n = 1). Aedeagal median lobe robust (Fig. 16E), but thinner than that of M. notobscuricornis (Fig. 16C), distance from parameral articulation to tip 3.6× depth at midlength, apex extended more than its breadth beyond ostial opening, tip tightly rounded; median lobe narrowed apically and curved to the right in ventral view, tip appearing bluntly rounded (Fig. 16F); internal sac with field of 5 large macrospicules, flagellar plate large and visible in uneverted specimen just basad spicular field.

Holotype

Male (CUIC) dissected and labeled: HI: Maui Haleakala N.P. / Kuiki, below el. 2164 m / N20°42.23', W156°08.00', / 16-V-2001 lot 05 sifting / ohia litter C.P. Ewing // Mecyclothorax / mordax / ♂ #1 / det. J.K. Liebherr 2014 // HOLOTYPE / Mecyclothorax / mordax / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Etymology

The adjectival epithet mordax means biting, corroding, or pungent, an appropriate name for a carabid beetle. But here it is also a play on the epithet daptinus—used by Sharp (1903) for a species of similar appearance—derived from the Greek dapto; to devour, or gnaw (Brown 1956).

Distribution and habitat

The lone specimen of this species was found near Kuiki (Fig. 19) in leaf litter taken from below an isolated ‘ōhi‘a tree growing at timberline (e.g. Fig. 5A).

Mecyclothorax mordicus sp. n.

Figs 15D, 16G–H, 19

Diagnosis

Of the pale margined species in this group from Haleakalā that exhibit a smooth pronotal disc, sinuate lateral pronotal margins and a broader pronotal base—MPW/BPW = 1.42–1.52—this species can be diagnosed by more convex eyes—ocular ratio = 1.44–1.55—and the subparallel pronotal lateral margins and protruded hind angles (Fig. 15D). The most similar species is M. manducus (Fig. 20A), which deviates by exhibiting smaller eyes—ocular ratio = 1.40–1.43. If a male is available, the aedeagus can settle the matter, with M. mordicus exhibiting a median lobe with a very short rounded apex distad the ostial opening (Fig. 16G), whereas the median lobe apex of M. manducus is elongate (Fig. 16I). Setal formula 2 1 2 1[sae]. Standardized body length 3.6–3.9 mm.

Figure 20.

Mecyclothorax obscuricornis group species, dorsal habitus view. A M. manducus (Kīpahulu, 910 m) B M. ambulatus (Haleakalā, 1500 ft., RCLP) C M. montanus (ESE Kuiki, 2145 m) D M. obscuricolor (Ukulele Camp, 1525–1980 m).

Description

(n = 4). Head capsule with frontal grooves broad at clypeus, a lateral carina to anterior supraorbital seta; dorsal impression of neck flat to concave; ocular lobe ratio = 0.75–0.77; labral anterior margin broadly, shallowly emarginate; antennae filiform, antennomere with sparse setae, antennomere 3 with pelage of short setae; mentum tooth with sides acute, apex rounded. Pronotum with lateral seta present, basal seta absent; hind angle obtuse, margin rounded posterad; lateral margin subparallel anterad hind angle then divergent; median base moderately depressed, covered with dense longitudinal wrinkles and some punctures; basal margin straight medially, slightly expanded posteriorly mesad laterobasal depressions; median longitudinal impression shallow, finely incised; anterior transverse impression deep, broader medially, lined with granulate isodiametric microsculpture and crossed by longitudinal wrinkles; anterior callosity elevated, flat, crossed by longitudinal wrinkles; front angles little projected, tightly rounded; front angles slightly farther apart than hind angles; APW/BPW = 1.03–1.04; lateral marginal depression moderately narrow, edge upturned; laterobasal depression smooth, concave, surface continuous with lateral depression. Proepisternum with 5 minute punctures along hind marginal groove; prosternal process medially depressed, sides broadly upraised. Elytra subquadrate, MEW/HuW = 1.81–1.86; disc moderately convex, sides more sloped; basal groove angled anterad from 3rd stria to meet tightly rounded humeral angle; parascutellar seta present; parascutellar striole with 3–5 punctures, striole shallow between punctures; sutural interval more convex than lateral intervals, sutural juncture upraised; sutural and 2nd striae of subequal depth from base to apex; intervals 2-8 convex, associated striae deep, minute irregularities present at base, smooth on disc and at apex; 7th and 8th interval of similar convexity mesad subapical sinuation; 2 dorsal elytral setae situated at 0.30× and 0.60× elytral length, anterior setal impression spanning interval 3, posterior impression spanning ½ of interval width; subapical seta present, apical seta absent; lateral elytral setae arranged as anterior series of 7 setae and posterior series of 6 setae; elytral marginal depression moderately narrow at humerus, broader posterad, beadlike at subapical sinuation; subapical sinuation shallow, more abruptly incurved anteriorly. Mesepisternum with ~4 shallow punctures in one row; metepisternal width to length ratio = 0.81; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1–5; suture between ventrites 2 and 3 complete; apical ventrite of male with 2 setae. Legs-metatarsomere 1/metatibial length ratio = 0.20; metatarsomere 4 length along outer lobe 1.25× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci narrow, lateral, median area broad. Microsculpture of vertex isodiametric sculpticells in transverse rows; pronotal disc with transverse mesh, sculpticell breadth 2× length; pronotal median base with transverse mesh, sculpticell breadth 2× length; elytral disc glossy, transverse mesh to transverse lines present laterally; elytral apex with shallow transverse mesh, sculpticell breadth 2–3× length; metasternum with distinct transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous; antennomere 1 flavous, antennomeres 2–3 rufoflavous, 4–11 rufobrunneous; pronotal disc rufopiceous, anterior callosity, lateral margins broadly, and median base rufoflavous; proepipleuron and proepisternum rufoflavous; elytral disc with intervals 2–5 piceous from base to apical 5/6, and interval 6 piceous on disc; sutural interval rufobrunneous basally and on disc, flavous in apical half; elytral intervals 7–9 plus marginal depression flavous, apex broadly flavous to juncture of intervals 3 and 4; elytral epipleuron pale creamy ivory, metepisternum rufobrunneous; abdomen with ventrites 1–3 medially and 4–6 mediobasally piceous; apical 2/3 of apical abdominal ventrite 6 flavous; metafemur flavous; metatibia flavous with brunneous cast.

Male genitalia (n = 2). Aedeagal median lobe gracile but with tip very broadly rounded and little extended beyond ostial opening, distance from parameral articulation to tip 4.4× depth at midlength (Fig. 16G); median lobe not curved to the right except near bluntly rounded tip in ventral view (Fig. 16H); internal sac unornamented, lightly sclerotized flagellar plate visible in lateral and ventral views (Figs 16G–H).

Holotype

Male (CUIC) dissected and labeled: HI: Maui Haleakala Hana / For. Res. Ridge E / Heleleikeoha Str. 12-V- / 1998 lot 09 1760 m el. / sifting ohia litter C.P. / Ewing // 2 // Mecyclothorax / mordicus / ♂ #2 / det. J.K. Liebherr 2014 // HOLOTYPE / Mecyclothorax / mordicus / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes

HI: Maui, Haleakala, Hana For. Res., Horseshoe Bog, sifting Metrosideros litter, 1830 m el., 12-v-1998 lot 08 (CUIC, 1), Kuhiwa Str., beating Myrsine lessertiana, 1780 m el., 12-v-1009 lot 13 (CUIC, 1), same data a holotype (CUIC, 1).

Etymology

The adjectival mordicus means biting in the mandibular sense, continuing the string of epithets that started with daptinus above.

Distribution and habitat

Recorded localities of M. mordicus are restricted the Hāna Bogs region, specifically to proximate locales at Horseshoe Bog and near the headwaters of Kuhiwa and Helele‘ike‘oha Streams (Fig. 19). Beetles of this species have been found in ‘ōhi‘a litter, and by beating Myrsine lessertiana (kolea lau nui).

Mecyclothorax manducus sp. n.

Figs 16I–J, 17C, 18C, 20A, 21

Diagnosis

Among the pale-margined species of this group, the slightly sinuate pronotal lateral margins associated with the obtuse pronotal hind angles of this species (Fig. 20A) are intermediate to the non-sinuate lateral margins of M. mordax (Fig. 15C) and the distinctly sinuate lateral margins of M. mordicus (Fig. 15D). This species is also characterized by less convex eyes—ocular ratio = 1.40–1.43—versus the more convex eyes of the other two species. Setal formula 2 1 2(3) 1[sae]; a third unilaterally present dorsal elytral seta was observed in one individual. Standardized body length 3.6–4.1 mm.

Description

(n = 5). Head capsule with frontal grooves broad near clypeus, a lateral carina present to anterior supraorbital seta; dorsal impression of neck flat to slightly concave; ocular lobe projected posteriorly, eye small, ocular lobe ratio = 0.71–0.74; labral anterior margin broadly, shallowly emarginate, antennomere 2 sparsely setose, antennomere with well-developed pelage of short setae; antennae filiform; mentum tooth with sides acute, apex tightly rounded. Pronotum with lateral seta present, basal seta absent; median base moderately depressed relative to disc, minutely punctate, minute wrinkles present on disc; basal margin straight medially, expanded posteriorly mesad laterobasal depressions; median longitudinal impression narrow, shallowly incised, continuous to basal margin; anterior transverse impression deep, narrow, surface behind with granulate isodiametric microsculpture, crossed by fine longitudinal wrinkles; anterior callosity slightly convex, glossy except for longitudinal wrinkles; front angles slightly projected, tightly rounded; APW/BPW= 1.00–1.04; lateral marginal depression narrow, edge upturned anteriorly, slightly broader, reflexed near base; laterobasal depression smooth, transversely wrinkled onto disc, continuous with lateral depression. Proepisternum with smooth hind marginal groove; prosternal process medially depressed, sides broadly upraised. Elytra subquadrate, disc moderately convex, sides more so; basal groove gently recurved to rounded humeral angle; MEW/HuW = 1.98–2.03; parascutellar seta present; parascutellar striole with three deep punctures, continuous between punctures; sutural interval more convex than lateral intervals, sutural juncture elevated; sutural and 2nd striae of subequal depth from base to apex; striae 2–8 of similar depth, associated intervals convex; striae 1–3 with small punctures that expand stria, striae 4–5 with slight irregularities; 7th and 8th interval similarly convex mesad subapical sinuation; 2 dorsal elytral setae at 0.27× and 0.63× elytral length (unilateral third seta at 0.48× length), setal impressions spanning 2/3 of interval 3; subapical seta present, apical seta absent; lateral elytral setae arranged in anterior series of 7 setae, posterior series of 6 setae; elytral marginal depression narrow at humerus, expanded laterally along sides, narrowly beaded at subapical sinuation; subapical sinuation shallow, more abruptly incurved anteriorly. Mesepisternum with ~5 very shallow punctures; metepisternal width to length ratio = 0.76; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1–5; suture between ventrites 2 and 3 reduced, effaced laterally; apical male ventrite with 2 marginal setae, female ventrite with 4 equally spaced marginal setae plus a median trapezoid of 4 smaller setae. Legs-metatarsomere 1/metatibial length ratio = 0.18; metatarsomere 4 length along outer lobe 1.25× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci narrow, lateral, median area broad. Microsculpture of vertex a well-developed isodiametric mesh in transverse rows; pronotal disc with well-developed transverse mesh, sculpticell breadth 2–3× length; pronotal median base with well-developed, upraised transverse mesh, sculpticell breadth 2× length; elytral disc with transverse mesh, sculpticell breadth 2–3× length; elytral apex with mixture of transverse mesh and transverse lines; metasternum with distinct transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous; antennomere 1 flavous, antennomeres 2–3 rufoflavous, 4–11 rufobrunneous; pronotal disc rufopiceous, pronotal margins broadly rufobrunneous, median base rufoflavous; proepipleuron rufoflavous, proepisternum rufobrunneous; elytral intervals 2–6 piceous from base to juncture of striae 3 and 4, outer intervals and apex flavous; sutural interval rufobrunneous basally, flavous in apical 1/3; elytral epipleuron rufoflavous, metepisternum rufobrunneous with piceous cast; abdomen with ventrites 1–5 rufopiceous medially, rufoflavous laterally; basal half of apical ventrite 6 rufopiceous, apical half flavous; metafemur flavous; metatibia flavous with brunneous cast.

Male genitalia (n = 2). Aedeagal median lobe moderately elongate, distance from parameral articulation to tip 3.7× depth at midlength (Fig. 16I); apical extension parallel sided, the tip subangulate at its ventral margin; median lobe apex curved to the right just before blunt tip in ventral view (Fig. 16J); internal sac unornamented, elongate flagellar plate visible inside dorsal margin of median lobe in lateral view.

Female reproductive tract (n = 1). Bursa copulatrix columnar, 0.57 mm long, 0.15 mm broad (Fig. 17C); bursal walls translucent, thinly wrinkled; gonocoxite 1 with 2–5 apical fringe setae, 8–9 small setae on medial surface (Fig. 18C); gonocoxite 2 subtriangular, apex acuminate; base evenly extended from lateral margin and basally curved at apex; 2 gracile lateral ensiform setae, apical nematiform setae on medial surface at 0.70× gonocoxite length.

Holotype

Female (CUIC) labeled: HI:Maui Haleakala N.P. / Kipahulu Vy. Central / Pali Tr. 910 m el. / 30-IV-1991 sifting / moss and leaf litter // J.K. Liebherr / A.C. Medeiros, / Jr. collectors // Mecyclothorax / manducus / ♀ photo / Det. J.K. Liebherr 2014 // HOLOTYPE / Mecyclothorax / manducus / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes

HI: Maui: Haleakala N.P., Kipahulu Vy., sift litter, 1800 m el., 08-v-1991 lot 04, Jessel/Medeiros (CUIC, 1), above Bravo Camp above, sift litter, 600 m el., 01-v-1991 lot 03, Liebherr/Medeiros (CUIC, 1), Central Pali Tr., sift leaf/moss litter, 915 m el., 30-iv-1991 lot 03, Liebherr/Medeiros (CUIC, 16), under boards/logs/tarps, 915 m el., 30-iv-1991 lot 02, Liebherr/Medeiros (CUIC, 1).

Etymology

This last of the species epithets related to biting, the Latin noun manducus means glutton (Brown 1956).

Distribution and habitat

M. manducus is known only from Kīpahulu Valley (Fig. 21), though it occupies habitats from 600–1800 m elevation there. Records are all from ground-level microhabitats. These predominantly include 17 specimens in four Winkler sifter samples of leaf and moss litter (2–3 l each) taken from near large koa and ‘ōlapa trees, but also one beetle from under boards, tarps and logs at an abandoned fence-building camp.

Figure 21.

Recorded geographic distributions of M. obscuricornis group species.

Mecyclothorax ambulatus sp. n.

Figs 16K–L, 20B, 21

Mecyclothorax n. sp. δ, Liebherr 2004: fig. 4.

Diagnosis

This species exhibits the most somber coloration in the group, the dorsal surface dark fuscous, and antennomeres 1–3 and femora only slightly paler (Fig. 20B). Elytral striae 1–5 are punctate basally, the punctures expanding strial breadth, a characteristic shared with the species triplet, M. waikamoi, M. poouli, and M. ahulili (Fig. 24B–D), however M. ambulatus exhibits larger body size; standardized body length 4.0 mm versus 2.9–3.4 mm in the other three species. Setal formula 2 1 2 0.

Description

(n = 1). Head capsule with frontal grooves broad near clypeus, a lateral carina present to anterior supraorbital seta; dorsal impression of neck flat to slightly concave; ocular ratio = 1.43, ocular lobe ratio = 0.81; labral anterior margin broadly, shallowly emarginate; antennae filiform, antennomere 2 sparsely setose, antennomere 3 with well-developed pelage of short setae; mentum tooth with sides acute, apex tightly rounded. Pronotum with lateral seta present, basal seta absent; MPW/BPW = 1.43; hind angle obtuse, apex rounded; lateral margin slightly divergent anterad hind angle, then more divergent anteriorly; median base moderately depressed relative to disc, sparsely covered with minute punctures, minute wrinkles present at juncture with disc; basal margin convexly expanded between laterobasal depressions; median longitudinal impression narrow, shallowly incised; anterior transverse impression narrow, finely incised, shallowest medially, crossed by fine wrinkles; anterior callosity elevated, flat, crossed by fine wrinkles; front angles slightly projected, tightly rounded; APW/BPW= 1.01; lateral marginal depression narrow, edge upturned anteriorly, beadlike at lateral sinuation and posterad laterobasal depressions; laterobasal depression smooth, continuous with lateral depression. Proepisternum with smooth hind marginal groove; prosternal process medially depressed, sides broadly upraised. Elytra broadly subquadrate; disc moderately convex, sides more so; basal groove recurved to subangulate humeral angle defined by a hitch at base of lateral marginal depression; MEW/HuW = 1.93; parascutellar seta present; parascutellar striole with 3 deep punctures, deep, continuous between punctures; sutural interval more convex than lateral intervals, sutural juncture elevated; sutural and 2nd striae of subequal depth base to apex; striae 1–8 deep, interval 8 convex mesad subapical sinuation; 2 dorsal elytral setae at 0.28–0.30× and 0.61–0.63× elytral length, setal impressions moderately deep, spanning 2/3 of interval 3; subapical and apical setae absent; lateral elytral setae arranged in an anterior series of 7 setae and a posterior series of 5 setae; elytral marginal depression broad with upraised margin at humerus, gradually narrowed but still evident before subapical sinuation. Mesepisternum with ~7 punctures in 2–3 irregular rows; metepisternal width to length ratio = 0.80; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1–5; suture between ventrites 2 and 3 reduced, effaced laterally; apical ventrite of male with 2 marginal setae. Legs-metatarsomere 1/metatibial length ratio = 0.19; metatarsomere 4 length along outer lobe 1.33× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci narrow, lateral, median area broad. Microsculpture of vertex a well-developed isodiametric mesh in transverse rows; pronotal disc with well-developed transverse mesh, sculpticell breadth 2–3× length; pronotal median base with well-developed, upraised transverse mesh, sculpticells twice as broad as long; elytral disc with mixture of transverse mesh and transverse lines; elytral apex with mixture of transverse mesh–sculpticell breadth 3× length–and transverse lines; metasternum with distinct transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex dark rufobrunneous; antennomeres 1–3 rufobrunneous, 4–11 rufopiceous; pronotal disc and margins concolorous, dark rufobrunneous; proepipleuron rufoflavous, proepisternum rufobrunneous; elytral disc dark rufobrunneous, sutural interval concolorous basally, slightly paler, rufoflavous at apex, elytral marginal depression and apex slightly paler, rufoflavous; elytral epipleuron rufoflavous, metepisternum rufobrunneous; abdomen rufobrunneous, apical 1/6 of apical ventrite 6 paler, flavous; metafemur rufobrunneous with piceous cloud covering basal 4/4; metatibia rufoflavous with piceous cast.

Male genitalia (n = 1). Aedeagal median lobe broad, long, distance from parameral articulation to tip 3.3× depth at midlength (Fig. 16K); apex evenly curved, extended for 3× its breadth beyond ostial opening, tip slightly flattened on dorsal aspect; median lobe distinctly curved to the right just before blunt apex in ventral view (Fig. 16L); internal sac with dark microspicules over surface, a short flagellar plate visible inside dorsal margin in lateral view.

Holotype

Male (BPBM) dissected, point mounted above original mounting platen, and labeled: Hal. Maui / 1500 ft. (on reverse) // obscuricolor / var. from lower / elevation. RCLP. // red rectangle // T. obscuricolor // Mecyclothorax / ambulatus / ♂ #1 / det. J.K. Liebherr 2014 // HOLOTYPE / Mecyclothorax / ambulatus / Liebherr / det. J.K. Liebherr 2015 (black-margined red label). The elevation of 1500 ft. along the Makawao-Paia road is designated the type locality.

Etymology

The past participle ambulatus means to have travelled or traversed, and is used to signify R.C.L. Perkins’ discovery of the single known specimen at 1500 ft. elevation on Haleakalā. This low elevation collecting site is interpreted to have been along his walk from Makawao, the home base of his mountain collecting, to Paia, the village where he purchased groceries (Manning 1986).

Distribution and habitat

M. ambulatus is a biogeographic relict, being labeled from Haleakalā, 1500 ft. by Perkins (Fig. 21). The designated type locality currently lies among agricultural fields and homesites near the town of Kamole, leading to the conclusion that this species is extinct near its only known locality.

Mecyclothorax montanus sp. n.

Figs 17D, 18D, 20C, 21, 22A–B

Diagnosis

The combination of quadrisetose pronotum, both lateral and basal setae present, subparallel to subovoid elytra, the lateral margins nearly straight along the anterior lateral setal series, and moderate body size, standardized body length, 3.4–3.8 mm, will diagnose this species. The pronotal and elytral margins are slightly paler than their respective discs (Fig. 20C), but not to the degree as in the paler-margined species treated above (Figs 15, 20A). This is also the only Haleakalā species of the group to exhibit both subapical and apical elytral setae; setal formula 2 2 2 2. Nevertheless, beetles of this species lack the parascutellar seta, and exhibit a reduced lateral elytral setal series, with base numbers of six anterior setae and five posterior setae.

Description

(n = 5). Head capsule with frontal grooves broad near clypeus, a lateral carina to anterior supraorbital seta; dorsal impression of neck flat to slightly concave; ocular lobe protruded, eyes small, ocular ratio = 1.36–1.38, ocular lobe ratio = 0.66–0.71; labral anterior margin broadly, shallowly emarginate; antennae submoniliform, antennomeres 2–3 sparsely setose; mentum tooth with sides acute, apex rounded. Pronotum quadrisetose, both lateral and basal setae present; MPW/BPW = 1.38–1.49; hind angle obtuse due to rounded margin behind; lateral margin parallel just anterad angle, then divergent; median base depressed relative to disc, a few large punctures and wrinkles present; basal margin broadly, slightly convex between laterobasal depressions; median longitudinal impression narrowly, shallowly incised, continuous to basal margin, adjoined by curved wrinkles emanating onto disc; anterior transverse impression deep, narrow, finely incised, crossed by fine longitudinal wrinkles; anterior callosity elevated, flat, crossed by fine wrinkles; front angles slightly projected, tightly rounded; APW/BPW = 0.94–1.03; lateral marginal depression narrow, edge upturned to beadlike at front, broader, less elevated to base; laterobasal depression surface impunctate with transverse wrinkles, continuous with lateral depression. Proepisternum with ~5 minute punctures along hind marginal groove; prosternal process medially depressed, sides broadly upraised. Elytra subparallel to subovoid, disc moderately convex, sides more so; basal groove evenly recurved to tightly rounded humeral angle; MEW/HuW = 1.80–2.00; parascutellar seta absent; parascutellar striole smooth, sinuous; sutural interval more convex than lateral intervals, sutural juncture upraised; sutural and 2nd striae of subequal depth from base to apex; discal striae 1–7 with small punctures that cause strial irregularities; 7th and 8th interval of similar convexity mesad subapical sinuation; 2 dorsal elytral setae at 0.28–0.35× and 0.59× elytral length; setal impressions moderate, spanning 2/3 of interval 3; apical and subapical setae present; lateral elytral setae arranged in anterior series of 6 setae, and posterior series of 5 setae (rarely 4 or 6 setae); elytral marginal depression narrow from humerus to midlength, gradually narrowed to bead at subapical sinuation; subapical sinuation shallow, more abruptly incurved anteriorly. Mesepisternum with ~7 punctures in 2–3 rows; metepisternal width to length ratio = 0.80; metepisternum/metepimeron suture distinct; metathoracic flight wing length to width ratio = 2.2, remnant R and M veins present, wing tip extended 2/3 distance to hind margin of metanotum. Abdomen with irregular lateral wrinkles on ventrites 1–5; suture between ventrites 2 and 3 complete; apical male ventrite with 2 marginal setae, apical female ventrite with 4 equally spaced marginal setae and median trapezoid of 4–5 short setae (the 5th seta, when present, shorter). Legs-metatarsomere 1/metatibial length ratio = 0.19; metatarsomere 4 length along outer lobe 1.28× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci narrow, lateral, median area broad. Microsculpture of vertex very shallow, transverse, sculpticell breadth 2× length; pronotal disc with shallow transverse mesh, sculpticell breadth 3× length; pronotal median base with shallow isodiametric and transverse mesh; elytral disc with shallow transverse mesh, sculpticells 2–3× length; elytral apex with shallow transverse mesh, sculpticell breadth 2× length; metasternum with distinct transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex glossy rufopiceous; antennomeres 1–3 flavous, 4–11 only slightly darker; pronotal disc rufopiceous; pronotal lateral margins, anterior callosity and median base rufoflavous to flavous at outer margins; proepipleuron flavous, proepisternum rufobrunneous; elytral intervals 2–8 rufopiceous, sutural interval rufoflavous basally, flavous apically; interval 9, marginal depression, and apical margin rufoflavous; elytral epipleuron flavous dorsally, rufoflavous along ventral margin, metepisternum rufobrunneous; abdomen with ventrites 1–5 rufopiceous medially, rufoflavous laterally; apical ventrite 6 flavous in apical half; metafemur flavous; metatibia flavous with brunneous cast.

Male genitalia (n = 1). Aedeagal median lobe gracile, distance from parameral articulation to tip 4.5× depth at midlength (Fig. 22A), apex broad, extended twice its breadth beyond ostial opening, tip flattened on dorsoapical aspect; median lobe slightly curved to the right before rounded tip in ventral view (Fig. 22B); internal sac covered with evident microspicules, a flagellar plate visible inside dorsal margin in lateral view (Fig. 22A).

Female reproductive tract (n = 1). Bursa copulatrix columnar, nearly as broad as vagina, length 0.54 mm, breadth 0.23 mm (Fig. 17D); bursal walls translucent, distinctly wrinkled; gonocoxite 1 with 3–4 apical fringe setae, 4–5 smaller setae on medial surface (Fig. 18D); gonocoxite 2 subtriangular, apex acuminate, lateral surface distinctly curved, 2 small lateral ensiform setae, apical nematiform setae on medial surface at 0.75× gonocoxite length.

Figure 22.

Male aedeagus, M. obscuricornis group species (for abbreviations see Table 2, p. 23). A–B M. montanus, right and ventral views (ESE Kuiki, 2145 m) C–D M. obscuricolor, right and ventral views (Ukulele Camp, 1525-1980 m) E–F M. obscuricornis, right and ventral views (Ukulele Camp 1525 m).

Holotype

Male (CUIC) dissected and labeled: HI: Maui Haleakala N.P. / Kuiki, below el. 2134 m / N20°42.23', W156°08.00', / 16-V-2001 lot 02 sift. / litter under ohia lehua / J.K. Liebherr // Mecyclothorax / montanus / ♂ #1 / Det. J.K. Liebherr 2014 // HOLOTYPE / Mecyclothorax / montanus / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes

HI: Maui: Haleakala N.P., Kipahulu Vy., sift litter by day, 2100 m el., 07-v-1991 lot 05, Jessel/Medeiros (CUIC, 2), Mauka Ridge, pyrethrin fog Metrosideros/moss, 2045 m el., 21-v-1998 lot 01, Polhemus (NMNH, 1), Kuiki, below, sift Metrosideros litter, 2145 m el., 16-v-2001 lot 02, Liebherr (CUIC, 6), pyrethrin fog Metrosideros/moss, 2145 m el., 16-v-2001 lot 01, Liebherr (CUIC, 1).

Etymology

The adjectival epithet montanus means of the mountains, which aptly fits the habits of this species distributed around the head of Kīpahulu Valley.

Distribution and habitat

M. montanus is distributed in the upper slopes surrounding the head of Kīpahulu Valley (Fig. 21). Beetles have been found in sifted leaf litter from the forest floor, and also in leaf and moss litter adhering to trunks of ‘ōhi‘a.

Mecyclothorax obscuricolor (Blackburn)

Figs 18E, 20D, 21, 22C–D, 23A

Cyclothorax obscuricolor Blackburn 1878a: 123; Blackburn and Sharp 1885: 215.

Thriscothorax obscuricolor, Sharp 1903: 266.

Mecyclothorax obscuricolor, Britton 1948b: 160.

Diagnosis

Of species in this group with concolorous pronotal discs and margins, this species exhibits the smoothest elytral striae, with only minute punctures basally in striae 1–7 that cause slight irregularities of the strial surface (Fig. 20D). The pronotal median base is moderately depressed relative to the disc, with longitudinal punctures and wrinkles producing a rough surface. The dorsal surface bears well-developed microsculpture, an isodiametric mesh on the vertex, and transverse mesh on pronotal and elytral discs with sculpticell breadth 2–3× length. Setal formula 2 1 2 1[sae]. Standardized body length 3.7–4.0 mm.

Identification

(n = 5). The eyes are little convex, ocular ratio = 1.36–1.42, and cover about ¾ of the ocular lobe; ocular lobe ratio = 0.71–0.82. The pronotal hind angles are obtuse, with the lateral margins divergent anteriorly from the angles. The pronotum is broad, MPW/PL = 1.31–1.33, with a moderately broad base, MPW/BPW = 1.40–1.52. The pronotal anterior transverse impression is deep, narrow, and crossed by deep wrinkles. The elytra are subquadrate with broad subangulate humeri, MEW/HuW = 1.78–1.95. Body coloration is quite uniform, with head and elytral disc rufobrunneous, and pronotal disc darker, rufopiceous. The legs are contrastedly paler, with metafemora rufoflavous with a piceous cloud over basal 1/3 of anterior surface, and the tibiae rufoflavous with a piceous cast, especially apically.

Male genitalia (n = 1). Aedeagal median lobe broad, robust, distance from parameral articulation to tip 3.2× depth at midlength (Fig. 22C); apex broadly extended beyond ostial opening, the apical face flat; median lobe curved to the right, tip appearing flat in ventral view (Fig. 22D); internal sac covered with fine microspicules, brown, round flagellar plate evident inside midlength of lobe shaft (Fig. 22C–D).

Female reproductive tract (n = 1). Bursa copulatrix broadly rounded, length 0.39 mm, breadth 0.34 mm (Fig. 23A); bursal walls thin, diaphanous; gonocoxite 1 with 3 apical fringe setae, the middle seta of series larger, 5 smaller setae on medial surface (Fig. 18E); gonocoxite 2 subtriangular, apex tightly rounded, base evenly extended from lateral margin, 2 lateral ensiform setae, the apical seta broader and longer, apical nematiform setae on medial surface at 0.75× gonocoxite length.

Figure 23.

Female bursa copulatrix and associated reproductive structures, M. obscuricornis group species, ventral view (for abbreviations see Table 2, p. 23). A M. obscuricolor (Ukulele Camp, 1525–1980 m) B M. obscuricornis (Ukulele Camp, 1525 m) C M. waikamoi (Waikamoi, 1265 m) D M. poouli (Kuhiwa, 1590 m). Scale bar = 0.50 mm.

Lectotype

Female (BMNH) hereby designated, labeled: mounting platen with Blackburn Maui code (Zimmerman 1957: 210), C. obscur. (on reverse) // Type // Hawaiian Is. Rev. T. Blackburn 1888-30 // LECTOTYPE Cyclothorax obscuricolor Blackburn J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat

M. obscuricolor was collected by R.C.L. Perkins in four different collecting lots (Nos. 112, 371, 372, and 622) that were derived from elevations ranging 1200–1980 m (Anonymous N D). Based upon the elevations and Perkin’s (1894) field notes, these localities spanned Olinda at lower elevations and Ukulele Camp and environs for the upper elevation localities (Fig. 21). No specific microhabitat may be ascribed to this species based on Perkins’ report (Perkins 1896c), and the species has not been recollected since 1896.

Mecyclothorax obscuricornis Sharp

Figs 18F, 22E–F, 23B, 24A, 25

Mecyclothorax obscuricornis Sharp 1903: 245; Britton 1948b: 160.

Diagnosis

The combination of standardized body length 3.4–3.6 mm, distinctly punctate discal elytral striae (Fig. 24A), convex lateral elytral margins, and narrowly paler pronotal and elytral margins serves to diagnose this species from others in the group. This species shares with M. obscuricolor well-developed isodiametric and transverse-mesh microsculpture on the vertex, however the pronotal disc has more transverse sculpticells–breadth 3× length to unconnected transverse lines–and the elytral disc has only a shallow transverse mesh, sculpticell breadth 2× length, with the surface glossy. In common with M. montanus, the parascutellar seta is lacking. Setal formula 2 1(2) 2 1[sae]; the species is scored for rare occurrence of both lateral and basal pronotal setae based on one individual with unilateral presence of the basal seta.

Figure 24.

Mecyclothorax obscuricornis group species, dorsal habitus view. A M. obscuricornis (Ukulele Camp, 1525 m) B M. waikamoi (Waikamoi, 1265 m) C M. poouli (Kuhiwa, 1590 m) D M. ahulili (Pu‘u Ahulili, 1600 m).

Identification

(n = 3). The eyes are little convex, ocular ratio = 1.37–1.40, and small, ocular lobe ratio = 0.74–0.79. The pronotum is moderately constricted basally, MPW/BPW = 1.43–1.46, with the lateral margins subparallel for only a short distance anterad the obtuse hind angles. The pronotal median base is moderately depressed and rugose due to the presence of large punctures and longitudinal wrinkles. The elytra are subquadrate with tightly rounded to subangulate humeral angles; MEW/HuW = 1.82–1.89.

Male genitalia (n = 2). Aedeagal median lobe (Fig. 22E) more gracile than that of M. obscuricolor (Fig. 22C), distance from parameral articulation to tip 4× medial breadth, apex narrow, parallel sided, extended 2.7× its breadth beyond ostial opening, the tip rounded; median lobe nearly straight in ventral view, right margin slightly concave before rounded tip (Fig. 22F); internal sac covered with evident microspicules, flagellar plate elongate, visible just inside dorsal margin in lateral view (Fig. 22E).

Female reproductive tract (n = 1). Bursa copulatrix columnar with rounded apex, length 0.83 mm, breadth 0.34 mm, base as broad as vagina (Fig. 23D); bursal walls translucent, thinly wrinkled; gonocoxite 1 with 2–3 apical fringe setae, 7–8 small setae on medial surface (Fig. 18F); gonocoxite 2 subfalcate, apex subacuminate, base extended laterally, 2 lateral ensiform setae, the apical seta broader and longer, apical nematiform setae on medial surface at 0.68× gonocoxite length.

Lectotype

Male (BMNH) hereby designated, labeled: Mecyclothorax obscuricornis Type D.S. Haleakala Perkins 120 (on mounting platen) // Type // Hawaiian Is. Perkins 1904-336 // LECTOTYPE Mecyclothorax obscuricornis Sharp J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat

Just as with M. obscuricolor above, M. obscuricornis was collected repeatedly by Perkins (Nos. 112, 113, 120, 251, 371, 372, 59 8, 600, 608) with his notes (Perkins 1894, 1896a, 1896b) placing those collecting activities in the vicinities of Olinda and Ukulele Camp (Fig. 25). Also, as with M. obscuricolor, this species has not been seen in nature Perkins collected it. In 1894 he collected both species on 31–iii, 1– iv, and 6–iv, supporting their occupation of similar or at least adjacent habitats during the late 19th Century.

Figure 25.

Recorded geographic distributions of M. obscuricornis group species.

Mecyclothorax waikamoi sp. n.

Figs 23C, 24B, 25, 26A, 27A

Diagnosis

This is the first of three very similar species, all characterized by small body size—standardized body length in this species = 2.9–3.4 mm—and subovoid elytra with variously punctate discal striae (Fig. 24B–D). The three species are all of dark coloration, with rufobrunneous head capsules, rufopiceous pronotal discs, and piceous elytral discs with narrowly paler, rufoflavous to flavous margins. Mecyclothorax waikamoi deviates from the other two in the well-developed punctation of elytral striae 1–6 in the basal half of the elytra (Fig. 24B). The eyes also tend to be less convex in this species—ocular ratio = 1.38–1.47—though that span overlaps the range of ocular ratios of the other two species at 1.43–1.51. The male aedeagus (Fig. 26A) can diagnose the species, with males of this species (Fig. 26A) exhibiting a broader, more apically flattened apex to the median lobe. Setal formula 2 1 2 0.

Figure 26.

Male aedeagus, M. obscuricornis group species (for abbreviations see Table 2, p. 23). A M. waikamoi, right view, sac everted (Waikamoi, 1305 m). B–D M. poouli, right view B (Kīpahulu, 910 m) C (Kuhiwa, 1590 m) D Sac everted (Helele‘ike‘oha, 1800 m) E M. ahulili, right view (Pu‘u Ahulili, 1600 m).

Description

(n = 5). Head capsule with frontal grooves broad near clypeus, a lateral carina to anterior supraorbital seta; dorsal impression of neck flat to slightly concave; labral anterior margin broadly, shallowly emarginate; antennae submoniliform, antennomere 2 sparsely setose, antennomere 3 with well-developed pelage of short setae; mentum tooth with sides acute, apex rounded. Pronotum broad, MPW/PL = 1.28–1.34, basally constricted, MPW/BPW = 1.47–1.54, with sinuate lateral margins anterad slightly obtuse hind angles (obtuse due to rounded basal margin inside angle); median base moderately depressed, sparsely punctate, shallow wrinkles at juncture with disc; basal margin broadly, slightly convex between laterobasal depressions; median longitudinal impression extremely shallow, narrowly incised; anterior transverse impression shallow, narrow, discontinuous medially; anterior callosity slightly convex, smooth; front angles slightly projected, rounded; distance between front and hind angles subequal, APW/BPW = 0.97–1.05; lateral marginal depression narrow, edge not upraised from front angle to lateral seta, very narrow and beadlike in basal half; laterobasal depression smooth, narrow, continuous with lateral depression. Proepisternum with ~5 minute punctures along hind marginal groove; prosternal process medially depressed, sides broadly upraised. Elytra subovoid and convex, sides and apex depressed relative to disc; basal groove evenly recurved to tightly rounded humeral angle; MEW/HuW = 1.95–2.03; parascutellar seta present; parascutellar striole with 3 punctures, discontinuous between punctures; sutural interval more convex than lateral intervals, sutural juncture elevated; sutural and 2nd striae of subequal depth and punctation from base to apex; striae 1–6 and 8 complete, stria 7 shallower, associated intervals convex; 7th and 8th interval of similar convexity mesad subapical sinuation; 2 dorsal elytral setae at 0.33× and 0.50× elytral length, setal impression small, spanning about half of interval 3; both apical and subapical setae absent; lateral elytral setae arranged as anterior series of 7(6) setae, and a posterior series of 5(4) setae; elytral marginal depression slightly broader at humerus, narrowed laterally to a beadlike margin at subapical sinuation; subapical sinuation very shallow, more abruptly incurved anteriorly. Metepisternum with ~5 very shallow punctures in 1 row; metepisternal width to length ratio = 0.84; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1–5; suture between ventrites 2 and 3 complete; apical male ventrite with 2 marginal setae, female apical ventrite with 4 equally spaced marginal setae and a median trapezoid of 4–6 short setae. Legs-metatarsomere 1/metatibial length ratio = 0.18; metatarsomere 4 length along outer lobe 1.33× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci narrow, lateral, median area broad. Microsculpture of vertex an obsolete transverse mesh, sculpticell breadth 2–3× length; pronotal disc with obsolete transverse mesh, sculpticell breadth 3× length, surface glossy; pronotal median base glossy with obsolete transverse sculpticells; elytral disc with shallow transverse mesh, sculpticell breadth 2–3× length, transverse lines present on lateral reaches of elytra; elytral apex with transverse sculpticells, breadth 2–3× length; metasternum with distinct transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex glossy rufobrunneous to rufopiceous; antennomeres 1–3 flavous, 4–11 rufobrunneous; pronotal disc rufobrunneous, lateral margins and base slightly paler, rufous; proepipleuron flavous, proepisternum rufoflavous to rufobrunneous; elytral disc rufopiceous on intervals 2–9, sutural interval rufoflavous from base, flavous apically; elytral marginal depression narrowly flavous, apex and intervals 8–9 near apex flavous; elytral epipleuron flavous dorsally, rufoflavous along ventral margin, metepisternum rufobrunneous; abdomen with ventrites 1–3 medially rufopiceous, ventrites 4–6 rufobrunneous, apical 1/3 of apical ventrite 6 flavous; metafemur flavous, basal half with brunneous to piceous cloud on anterior surface; metatibia rufoflavous with brunneous cast.

Male genitalia (n = 3). Aedeagal median lobe distinctly curved dorsally, robust, distance from parameral articulation to tip 2.7× maximum breadth dorsad ostial opening (Fig. 26A); dorsal surface expanded at midpoint of ostial opening, apex downturned with apical face flat; internal sac unornamented, lightly spiculated, flagellar plate moderately elongate, length of sclerotized ventral face 0.43× distance from parameral articulation to apex.

Female reproductive tract (n = 1). Bursa copulatrix a very short, broad pouch, length 0.17 mm, breadth at base 0.25 mm (Fig. 23C); bursal walls thin, transparent, not wrinkled; gonocoxite 1 with 3 apical fringe setae (Fig. 27A), 4 smaller setae on medial surface; gonocoxite 2 subtriangular, apex pointed, base little extended laterally, 2 short lateral ensiform setae, the apical seta distinctly broader, apical nematiform setae on medial surface at 0.70× gonocoxite length.

Figure 27.

Left female gonocoxa, M. obscuricornis group species, ventral view. A M. waikamoi (Waikamoi, 1265 m) B M. poouli (Kuhiwa, 1590 m).

Holotype

Male (BPBM) dissected, platen mounted and labeled: ♂ (glued to mounting platen) // Waikamoi, Maui / 4000', VII-1956 // R. Namba / Collector // Mecyclothorax / waikamoi / ♂ #5 / det. J.K. Liebherr 2014 // HOLOTYPE / Mecyclothorax / waikamoi / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Allotype

Female (CUIC) labeled: HI:Maui Haleakala / Waikamoi N.C.P. Ukulele / Pipeline 7-V-1998 lot05 / 1550 m el. pyrethrum fog / mossy ohia J.K. Liebherr // 4 // Mecyclothorax / waikamoi / ♀ photo // ALLOTYPE / (same labeling as Holotype).

Paratypes

HI: Maui: Koolau For. Res., Kula Pipeline Rd., pyrethrin fog log, 1305 m el., 18-v-2003 lot 09, Polhemus (NMNH, 3), pyrethrin fog Metrosideros, 1265 m el., 18-v-2003 lot 08, Polhemus (NMNH, 2); Waikamoi N.C.P., Honomanu drainage transect 3, sift litter, 1700 m el., 10-iv-1991 lot 01, Liebherr (CUIC, 1) scraping Metrosideros humus/moss, 1700 m el., 08-v-1991 lot 03, Liebherr (CUIC, 1).

Etymology

The species epithet waikamoi is taken from the Hawaiian Waikamoi, the name of the Maui land section and stream that is translated from Hawaiian as “water of the ruler’s taro (Pukui et al. 1974).”

Distribution and habitat

M. waikamoi is a species of ‘Ōhi‘a Montane Mesic to Wet Forest from 1200–1700 m elevation in the Waikamoi and Honomanu drainages (Fig. 25). It has been found in ground litter and in mossy humus on the trunks, and in the crotches of ‘ōhi‘a trees.

Mecyclothorax poouli sp. n.

Figs 23D, 24C, 25, 26B–D, 27B

Diagnosis

Distinguished from M. waikamoi, above, by the less punctate elytral striae (Fig. 24B, C) and the slightly larger, more convex eyes; ocular ratio = 1.43–1.48, ocular lobe ratio = 0.79–0.86. Distinguishable from M. ahulili by the subparallel pronotal lateral margins anterad the obtuse to nearly right hind angles (Fig. 24C), versus the divergent lateral margins and obtuse rounded hind angles of M. ahulili (Fig. 24D). The male aedeagal median lobe apex of this species (Fig. 26B–D) differs distinctively from the very short and broad apex characterizing M. ahulili (Fig. 26E), and the flagellar plate is larger than observed in M. waikamoi (Fig. 26A). Setal formula 2 1 2 0. Standardized body length 3.2–3.4 mm.

Description

(n = 5). [The description of M. waikamoi serves equally well for this species with the following substitutions.] Eyes moderately developed, ocular ratio = 1.43–1.48, ocular lobe ratio 0.79–0.86; pronotum variably broad, MPW/PL = 1.30–1.37; pronotal hind angles obtuse to nearly right, margin rounded behind; pronotal lateral margins subparallel for short distance anterad hind angles, MPW/BPW = 1.49–1.53; elytra may be narrower across the humeri in some individuals, MEW/HuW = 1.97–2.08; elytral sutural stria with minute irregularities in basal half but without distinct punctures, smooth and deep apically; parascutellar striole with 3 punctures, striole continuous between punctures; lateral elytral setal series arranged as 6-7 setae in anterior series, 5(4) in posterior series; only 4 setae observed in the median trapezoidal setal patch of the female apical abdominal ventrite; metafemora with brunneous cloud on basal anterior surface.

Male genitalia (n = 4). Aedeagal median lobe distinctly curved dorsally, robust, distance from parameral articulation to tip 2.7–3.0× maximum breadth dorsad ostial opening (Figs 26B–D); dorsal surface evenly curved at midpoint of ostial opening, apex downturned with apical face convex to briefly flattened, the flat surface shorter than in M. waikamoi (Fig. 26A); internal sac unornamented, lightly spiculated, flagellar plate large (Fig. 26D), length of sclerotized ventral face 0.55× distance from parameral articulation to apex.

Female reproductive tract (n = 1). Bursa copulatrix a triangular tentlike pouch, length 0.32 mm, basal breadth at vagina 0.33 mm (Fig. 23D); bursal walls thin, transparent; gonocoxite 1 with 2 apical fringe setae, 5–6 small setae on medial surface (Fig. 27B); gonocoxite 2 subtriangular, apex rounded, 2 lateral ensiform setae with apical seta broader and longer, apical nematiform setae on medial surface at 0.72× gonocoxite length.

Holotype

Male (CUIC) labeled: HI:Maui Haleakala / Hanawi N.A.R. Poouli / Cabin 5-V-1998 lot02 / 1590m el. pyr. fog ohia / + Cibotium J.K. Liebherr // Mecyclothorax / poouli / ♂ photo / det. J.K. Liebherr 2014 // HOLOTYPE / Mecyclothorax / poouli / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes

HI: Maui: Haleakala N.P., Kipahulu Vy., Central Pali Tr., sifting leaf/moss litter, 915 m el., 30-iv-1991 lot 03, Liebherr/Medeiros (CUIC, 2), 1200 m el., 29-iv-1991 lot 03, Liebherr/Medeiros (CUIC, 2); Hana For. Res., Heleleikeoha Str. State Fence Camp, pyrethrin fog Metrosideros/moss, 1615 m el., 11-v-1998 lot 06, Polhemus (NMNH, 1), 12-v-1998 lot 04, Liebherr (CUIC, 1), 1795 m el., 12-v-1998 lot 11, Polhemus (NMNH, 2); Koolau For. Res., Hanawi N.A.R., Kuhiwa Vy. E rim, pyrethrin fog Cibotium, 915 m el., 10-vi-1999 lot 04, Polhemus (NMNH, 2), pyrethrin fog Metrosideros, 880 m el., 09-vi-1999 lot 09, Polhemus (NMNH, 1), Kuhiwa Vy., Poouli Cabin, pyrethrin fog Metrosideros/Cibotium, 1590 m el., 05-v-1998 lot 02, Liebherr (CUIC, 7), pyrethrin fog Metrosideros/moss, 1590 m el., 05-v-1998 lot 01, Liebherr (CUIC, 2), lot 03, Polhemus (NMNH, 4).

Etymology

The po‘o uli (Melamprosops phaeosoma Casey and Jacoby 1974) was a member of the Hawaiian drepanid finches first discovered in 1973 in the Hanawī rainforest. By 2004 it was extinct (Powell 2008). The Hawaiian species epithet is meant as a memorial to the birds that may have fed on the ancestors of the type series of Mecyclothorax poouli.

Distribution and habitat

M. poouli occupies ‘Ōhi‘a-Hāpu‘u (Metrosideros-Cibotium) Wet Forest in the Hāna Bogs, and Kuhiwa and Kīpahulu Valleys (Fig. 25). Known localities span 900–1800 m elevation. The beetles have been discovered in moss and leaf litter at ground level, and in mossy epiphytic growths on ‘ōhi‘a trunks and downed nurse logs.

Mecyclothorax ahulili sp. n.

Figs 24D, 25, 26E

Diagnosis

This species exhibits strial punctation intermediate to M. waikamoi and M. poouli (Fig. 24B–D)—the sutural stria bears minute punctulae associated with irregularities in the strial orientation—plus the briefest sinuation of the pronotal lateral margin anterad the hind angle. The pronotal lateral marginal depression is also somewhat broader, especially at the front angle where it is almost explanate. The male aedeagal median lobe exhibited by males of this species is very different from those present in males of the other two species, with the apex very brief and ventrally subangulate (Fig. 26E). The median lobe is also shorter and more robust overall than those seen in males of the other two species. Setal formula 2 1 2 0. Standardized body length 2.9–3.2 mm.

Description

(n = 4). [As for M. poouli above, the description of M. waikamoi serves for M. ahulili with the following substitutions.] Eyes larger, more convex, ocular ratio = 1.46–1.51, ocular lobe ratio = 0.83–0.85; pronotum variably broad, MPW/PL = 1.27–1.35, basally constricted, MPW/BPW = 1.49–1.56; elytra slightly broader across humeri, MEW/HuW = 1.98–2.04; 5 setae observed in the median trapezoidal setal patch of the female apical abdominal ventrite; metafemora with brunneous cloud on basal anterior surface.

Male genitalia (n = 1). Aedeagal median lobe very broad, robust, distance from parameral articulation to tip 2.2× depth at midlength (Fig. 26E); apex very briefly extended beyond ostial opening, length of extension subequal to breadth, apical face slightly flattened; internal sac lightly spiculated, flagellar plate visible in uneverted specimen, plate length 0.49× distance from parameral articulation to tip.

Holotype

Male (CUIC) dissected and labeled: HI: Maui Haleakala N.P. / Kekuewa Hill 0.7 km N / Puu Ahulili sift moss & / humus 16-V-1993 lot 02 / el. 1600 m // J.K. Liebherr & / A.C. Medeiros / collectors // 3 // Mecyclothorax / ahulili / ♂ #7 / det. J.K. Liebherr 2014 // HOLOTYPE / Mecyclothorax / ahulili / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes

HI: Maui, Haleakala N.P., Kipahulu west rim ESE Kuiki, sifting Metrosideros litter, 1830 m el., 12-v-1998 lot 08, Liebherr/Medeiros (CUIC, 1), Kekuewa Hill 0.7 km N Puu Ahulili, sifting humus/moss, 1600 m el., 16-v-1998 lot 02 (CUIC, 1), lot 03 (CUIC, 1), Kaapahu, 1250 m el., 7-iv-2004 lot 01, Kaholoa‘a (BPBM, 1).

Etymology

The Hawaiian species epithet ahulili is based on the peak Pu‘u Ahulili that is near the type locality for this species. ‘Ahulili means glowing or dazzling (Pukui et al. 1974), though being a Hawaiian word it is to be treated as a noun.

Distribution and habitat

M. ahulili is known from three localities on the Manawainui Planeze (Fig. 25) that range 1250–1805 m elevation. All specimens have been found in ‘Ōhi‘a Montane Wet Forest within moss, leaf and humus litter at ground level, though the beetles should also be found on mossy trunks as for the prior two closely related species.

Mecyclothorax robustus species group

Diagnosis. Species in this group are characterized by: 1, uniformly darker dorsal body coloration, often with a bronzed or purplish reflection, though pronotal and elytral margins may be somewhat paler, rufobrunneous to rufoflavous; 2, larger body size, standardized body length = 4.1–6.3 mm; 3, regular elytral striation with adjacent striae not approaching or anastomosing except approaching the elytral apex. Among Haleakalā species the setal formula is 2 2 2 2, with the exceptions of M. consanguineus, characterized by loss of the apical elytral seta and instability for bilateral presence of the basal pronotal setae, and M. cognatus with rare individuals lacking one of the lateral pronotal setae.

Membership and distribution. The 11 Haleakalā species are complemented by a lone species—M. chalcosus Sharp—from West Maui (Liebherr 2011), two species from Moloka‘i (Liebherr 2007), and four species from the Big Island of Hawai‘i (Liebherr 2008b).

Key to adults of the Mecyclothorax robustus species group, Haleakalā volcano, Maui, Hawai‘i

1 Pronotum more cordate, constricted basally, MPW/BPW = 1.31–1.60 (Figs 28B–C, 33, 38) 2
1’ Pronotum more quadrate, not constricted basally, MPW/BPW = 1.17–1.29 (Fig. 28A) (016) M. aeneipennis Liebherr
2(1) Elytra short relative to breadth, orbicular, lateral margins convex from humerus to subapical sinuation (Figs 28B–C, 33A–B) 3
2’ Elytra longer, lateral margins straight, though perhaps divergent between humerus and subapical sinuation (Figs 33C–D, 38) 6
3(2) Eyes more convex, ocular ratio = 1.39–1.51 (Figs 28C, 33, 38) 4
3’ Eyes less convex, ocular ratio = 1.35 (Fig. 28B) (017) M. affinis sp. n.
4(3) Body narrower overall or forebody narrow relative to orbicular elytra (Figs 33, 38), pronotal lateral margin narrowly upraised mesad basal sinuation, the surface evenly elevated from laterobasal depression to margin, lateral marginal depression narrowly upraised at midlength 5
4’ Body broader, more robust, pronotal lateral margin explanate at basal sinuation, moderately broad at midlength (Fig. 28C) (018) M. cognatus Sharp
5(4) Pronotum cordate with glabrous hind angles; elytra very narrow basally, ovoid, MEW/HuW = 1.76, elytral basal groove broadly rounded at humerus (Fig. 33A); discal elytral striae finely inscribed, associated intervals convex, bearing transverse-line microsculpture not arranged in a distinct mesh (019) M. anchisteus sp. n.
5’ Pronotum broader basally, quadrisetose; elytra moderately narrow basally, subquadrate, MEW/HuW = 1.91–2.04, elytral basal groove angled anteriorly at humerus resulting in hitched humeral angle (Fig. 33B); discal elytral striae more broadly impressed, associated intervals only moderately convex, covered with well-defined transverse-mesh microsculpture, sculpticell breadth 3–4× length (020) M. consanguineus sp. n.
6(2) Discal elytral striae 1-6 smooth to indistinctly punctate in basal half, if punctulae are present at the deepest portions of striae, they are elongate and do not expand strial breadth (Fig. 33C–D) 7
6’ Discal elytral striae 1–6 distinctly punctate in basal half (Fig. 38) 8
7(6) Eyes less convex, ocular ratio = 1.42 (Fig. 33C); pronotal disc covered with granulate isodiametric microsculpture (021) M. aeneus Sharp
7’ Eyes more convex, ocular ratio = 1.46–1.50 (Fig. 33D); pronotal disc covered with transverse mesh microsculpture, sculpticell breadth 2–3× length (022) M. antaeus sp. n.
8(6) Body size smaller, standardized body length 4.1–4.7 mm 9
8’ Body size larger, standardized body length 4.8–6.2 mm 10
9(8) Elytra with isodiametric microsculpture on sutural interval near base, a mixture of distinct isodiametric to transverse-mesh sculpticells basally on intervals 2–6, sculpticell breadth up to 4× length (023) M. cymindicus Sharp
9’ Elytra with transverse-mesh microsculpture on sutural interval near base, transverse lines without formation of mesh on lateral intervals (024) M. cymindulus sp. n.
10(8) Discal elytral striae 2–4 distinctly punctate throughout length, or at least to position behind posterior dorsal seta (Fig. 38C–D); eyes larger, more convex, ocular ratio = 1.48–1.54, ocular lobe ratio = 0.76–0.84; male aedeagal median lobe apex dorsally expanded distad ostium (Fig. 41); internal sac ventrally covered with field of elongate, brunneous microsetae, a field of larger spicules may be present (Fig. 41B, E, G) (025) M. robustus (Blackburn)
10’ Dorsal elytral striae 2–4 distinctly punctate only in basal portion before anterior dorsal seta, the punctures associated with change in orientation of stria in some instances, or with expansion of strial breadth in others (Fig. 38E); eyes smaller, less convex, ocular ratio = 1.41–1.49, ocular lobe ratio = 0.70–0.78; male aedeagal median lobe apex parallel sided distad ostium, evenly downturned to tightly rounded apex (Fig. 43), internal sac with ventral surface bearing very short, pale microsetae and a small field of larger spicules (Fig. 43B, F, H) (026) M. haydeni sp. n.

Mecyclothorax aeneipennis Liebherr

Figs 28A, 29A–C, 30A, 31A, 32

Mecyclothorax aeneipennis Liebherr 2005b: 123.

Diagnosis

Among Haleakalā species of this group, M. aeneipennis exhibits the most quadrate pronotum, with the lateral margins little sinuate outside the laterobasal depressions (Fig. 28A); MPW/BPW = 1.17–1.29, versus MPW/BPW = 1.34–1.57 for all other Haleakalā species in this group. The elytral intervals are slightly convex, with discal striae 1–5 lined with small but distinct punctures in their basal halves to 2/3 of length. At the elytral apex, the 8th interval is more convex than the fused apical portion of intervals 5 + 7. The vertex is rufobrunneous, elytral disc slightly darker rufopiceous, and elytral disc rufopiceous with a cupreous reflection. The legs are contrastedly paler; femora flavous and tibiae flavous with a brunneous cast. Setal formula 2 2 2 2. Standardized body length 5.4–6.3 mm.

Figure 28.

Mecyclothorax robustus group species, dorsal habitus view. A M. aeneipennis (Polipoli, 1775 m) B M. affinis (West Wailuanui, 1950 m) C M. cognatus (Ukulele Camp Pipeline, 1510 m).

Identification

(n = 5). The eyes are moderately convex, ocular ratio = 1.41–1.50, ocular lobe ratio = 0.73–0.81. The elytra are quadrate, with the basal groove evenly recurved to the tightly rounded to subangulate humerus, the lateral marginal depression broad with margin upraised behind the humeral angle; MEW/HuW = 1.68–1.78. The dorsal body surface bears well-developed microsculpture: 1, vertex and pronotal disc with transverse mesh, sculpticell breadth 2× length; 2; 2, pronotal median base with mixture of granulate isodiametric and transverse-mesh microsculpture; 3, elytral disc with distinct granulate isodiametric mesh; and 4, elytral apex with a transverse mesh, sculpticell breadth 3–4× length.

Male genitalia (n = 2). Aedeagal median lobe gracile, distance from parameral articulation 4.2× median breadth (Fig. 29A), apex narrowly extended beyond ostial opening, the tip flattened on dorsoapical aspect, tightly rounded ventrally; median lobe straight in ventral view, the right margin slightly concave before blunt tip, the left margin curved rightward to meet apical extension (Fig. 29B); internal sac with well developed, dorsal and ventral microtrichial patches, both composed of stout spicules (Fig. 29C); flagellar plate with internal face well sclerotized, length of plate 0.40× distance from parameral articulation to tip.

Figure 29.

Male aedeagus, M. robustus group species (for abbreviations see Table 2, p. 23). A–C M. aeneipennis A–B Right and ventral views (Polipoli, 1878 m) C Right view, sac everted (Polipoli, 1776 m) D M. affinis, right view (West Wailuanui, 1950 m) E–H M. cognatus (Honomanu, 1850 m) E Right view, sac everted F Left view, sac everted G Right view, sac inverted H Ventral view.

Female reproductive tract (n = 1). Bursa copulatrix columnar with expanded apex, length 1.2 mm, apical breadth 0.57 mm, basal breadth 0.40 mm (Fig. 30A); bursal base translucent with thick wrinkles, apex more transparent, little wrinkled; gonocoxite 1 with 4 apical fringe setae, a small seta unilaterally present at medial apex, otherwise 7–10 small setae on medial surface (Fig. 31A); gonocoxite 2 narrowly subtriangular with broad apex and tightly rounded tip, base broadly extended laterally, 2 lateral ensiform setae with apical seta broader and longer, apical nematiform setae on medioventral surface at 0.71× gonocoxite length.

Figure 30.

Female bursa copulatrix and associated reproductive structures, M. robustus group species, ventral view (for abbreviations see Table 2, p. 23). A M. aeneipennis (Polipoli, 1890 m) B M. cognatus (Ukulele Camp, 1525 m) C M. consanguineus (Honomanu, 1850 m) D M. aeneus (Honomanu, 1820–1850 m) E M. antaeus (ESE Kuiki, 1850 m) F M. cymindicus (Ukulele Camp Pipeline, 1495–1525 m). Scale bar = 0.50 mm.

Figure 31.

Left female gonocoxa, M. robustus group species, ventral view. A M. aeneipennis (Polipoli, 1890 m) B M. cognatus (Ukulele Camp, 1525 m) C M. consanguineus (Honomanu, 1850 m) D M. aeneus (Honomanu, 1820–1850 m).

Holotype

Male (CUIC) designated by Liebherr (2005b). Type locality: HI: Maui, Haleakalā, Polipoli S.R.A., 1890 m el.

Distribution and habitat

M. aeneipennis is restricted to the forests near Polipoli Springs on the southwest rift of Haleakalā (Fig. 32). At the time this area was surveyed it was extensively afforested with exotic gymnosperms, especially Pinus radiata. Many of these trees had lodged, creating tangles of old logs with loose bark. Beetles were found under loose bark of downed logs, under logs on the ground, or by grubbing the Pinus leaf litter; i.e., pushing the litter aside to expose an area of soil and waiting for beetles to run into the arenalike opening. Mecyclothorax aeneipennis individuals were also found in more native situations, such as in mossy litter, or among tangles of Dryopteris fern stems.

Figure 32.

Recorded geographic distributions of M. robustus group species.

Mecyclothorax affinis sp. n.

Figs 28B, 29D, 32

Diagnosis

Like M. aeneipennis in the quadrate elytra with broad humeri—MEW/HuW = 1.76—but with cordate pronotum, the lateral margins slightly convergent anterad the projected, right hind angles (Fig. 28B). The eyes are relatively flat, ocular ratio = 1.35, and the ocular lobes project abruptly from the gena; a slotlike impression at the juncture of gena and ocular lobe. The single specimen, which does not appear teneral, has the pronotal and elytral lateral marginal depressions paler than the discs, the pronotal margins rufobrunneous versus the rufopiceous disc, and the elytral marginal depression narrowly rufoflavous versus the rufopiceous disc. Moreover, this is the only Haleakalā species in the group to be characterized by absence of the parascutellar seta. Setal formula 2 2 2 2. Standardized body length 4.5 mm.

Description

(n = 1). Head capsule with frontal grooves broad near clypeus, a lateral carina to anterior supraorbital seta, dorsal surface of neck slightly concave; labral anterior margin broadly, shallowly emarginate; antennae filiform, antennomeres 2–3 with sparse pelage of short setae; mentum tooth with sides acute, apex tightly rounded. Pronotum moderately transverse, MPW/PL = 1.30, base moderately constricted, MPW/BPW = 1.38; median base depressed relative to disc, surface strigose with fine longitudinal wrinkles; basal margin slightly convex between the laterobasal depressions; median longitudinal impression shallow, very finely incised at depth, joined by irregular transverse wrinkles; anterior transverse impression deep, finely incised at depth, separate from discal intervals; anterior callosity moderately convex, crossed by shallow wrinkles; front angles slightly projected, apex tightly rounded; APW/BPW = 0.99; lateral marginal depression slightly broader at front angle, moderately narrow behind, edge upturned; laterobasal depression smooth, laterally elevated to projected lateral margin. Proepisternum with smooth marginal groove; prosternal process medially depressed, upraised laterally to narrow bead anterad coxa. Elytra with convex disc, sides progressively sloped laterad; basal groove recurved medially, straight laterally to subangulate humerus; parascutellar striole shallow, with 3–4 punctures; sutural interval flat basally, convex at suture from disc to apex; sutural and 2nd striae of subequal depth from base to apex; intervals 2–5 moderately convex, associated striae with minute punctulae causing strial irregularities, all striae smooth and deep apically; 7th and 8th intervals of similar convexity mesad subapical sinuation; 2 dorsal elytral setae at 0.25× and 0.61–0.63× elytral length, setal impressions extended over 2/3 of interval 3; both apical and subapical setae present; lateral elytral setae arranged as an anterior series of 7 setae and a posterior series of 6 setae; elytral marginal depression moderately broad throughout length until reduced to beadlike margin from subapical sinuation to apex; subapical sinuation shallow, more abruptly incurved anteriorly. Mesepisternum with ~8–9 punctures in 2–3 rows; metepisternal width to length ratio = 0.83. Abdomen with irregular lateral wrinkles on abdominal ventrites 1–5; suture between ventrites 2 and 3 complete; apical ventrite of male with 2 marginal setae. Legs-metatarsomere 1/metatibial length ratio = 0.20, metatarsomere 4 length along outer lobe 1.2× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci very broad, median area rough to carinate. Microsculpture of vertex isodiametric to slightly transversely stretched in rows; pronotal disc with transverse mesh, sculpticell breadth 2–3× length; pronotal median base with isodiametric to transverse mesh; elytral disc with transverse mesh, sculpticell breadth 3× length, to transverse lines; elytral apex with shiny transverse mesh, sculpticell breadth 2–3× length; metasternum with distinct transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous; antennomere 1 flavous, antennomeres 2–3 rufoflavous, 4–11 rufobrunneous; pronotal disc rufopiceous; pronotal margins rufobrunneous in depression, lateral bead darker, rufopiceous; proepipleuron rufoflavous, proepisternum dark rufobrunneous; elytral disc rufopiceous; sutural interval basally rufobrunneous, apically rufoflavous to flavous; elytral margins and apex narrowly rufoflavous; elytral epipleuron rufoflavous laterally, rufobrunneous ventrally, metepisternum rufopiceous; abdomen medially rufopiceous, laterally rufobrunneous; abdominal apical ventrite with narrowly paler margin, rufobrunneous; metafemur flavous with piceous cloud on basal 2/3; metatibia rufobrunneous.

Male genitalia (n = 1). Aedeagal median lobe gracile, distance from parameral articulation to tip 4× median breadth (Fig. 29D), apex elongate, with narrow extension beyond ostial opening and dorsoventrally expanded, spoonlike tip; internal sac without apparent microtrichial patches, moderately elongate flagellar plate visible dorsad parameral articulation in uneverted specimen, flagellar plate length 0.42× distance from parameral articulation to tip.

Holotype

Male (BPBM) dissected and labeled: HAWAIIAN ISLANDS / Maui, Haleakala / Waikau Cabin 6400', / VI-18-1975 // R. Burkhart / Collector // ACC. NO. 1990.009 / BISHOP Museum // HOLOTYPE / Mecyclothorax / affinis / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Etymology

The Latin adjective affinis—meaning related to or neighboring—is used for this species to signify its close relationship to M. cognatus, a species named with the Latin word that means kindred or related (Brown 1956).

Distribution and habitat

The lone specimen representing this species was collected at Waikau Cabin (Fig. 32) without any associated ecological information.

Mecyclothorax cognatus Sharp

Figs 28C, 29E–H, 30B, 31B, 32

Mecyclothorax cognatus Sharp 1903: 255; Britton 1948b: 165.

Atelothorax optatus Sharp 1903: 269; Britton 1948b: 165 (synonymy).

Diagnosis

Among the mid-sized species in this group—standardized body length 4.7–5.7 mm—this species exhibits the broadest body in both pronotal and elytral dimensions. The pronotum is transverse, MPW/PL = 1.26–1.33, and basally broad, MPW/BPW = 1.31–1.42. This species is broadly sympatric in the Waikamoi area with M. consanguineus, the species most similar in appearance and thus likely to cause confusion. Mecyclothorax cognatus can be distinguished by the broad elytra (Fig. 28C), with broad humeri, MEW/HuW = 1.83–1.94 versus MEW/HuW = 1.91–2.04 for M. consanguineus (Fig. 33B). The pronotum of M. cognatus also exhibits more broadly explanate lateral margins just before the hind angles, that area broadly extended from the deep, smooth laterobasal depressions. Mecyclothorax consanguineus conversely exhibits less explanate lateral margins at that position. If a male is available, the aedeagal tip is absolutely diagnostic even if extended only slightly from the specimen. Those of M. cognatus males have an angulate apex with subangulate tip (Fig. 29E–G), whereas those of M. consanguineus males have an elongate apex with a mucronate tip (Fig. 34A–I). Sharp (1903) described Atelothrus optatus based his interpretation that the lateral pronotal setae were missing in the unique type specimen. The left lateral seta is indeed absent, but the articulatory socket for the right lateral seta is evident, resulting in the species setal formula being scored here as 2 2(1) 2 2.

Figure 33.

Mecyclothorax robustus group species, dorsal habitus view. A M. anchisteus (Kīpahulu, 1960 m) B M. consanguineus (Ukulele Camp Pipeline, 1510 m) C M. aeneus (Honomanu, 1820–1850 m) D M. antaeus (ESE Kuiki, 2145 m).

Figure 34.

Male aedeagus, M. robustus group species (for abbreviations see Table 2, p. 23). A–I M. consanguineus. A Right view, sac everted (Ukulele Camp Pipeline, 1534 m) B–C Right and ventral views (Ukulele Camp Pipeline, 1534 m) D Right view (Honomanu, 1750 m). E Right view (ESE Kuiki, 2164 m) F Right view (ESE Kuiki, 2135 m) G Right view (Paliku, 1900 m) H–I Right view (Kīpahulu, 1960 m) J–L M. antaeus J Right view, sac everted (ESE Kuiki, 2145 m) K–L Right and left views (ESE Kuiki, 2105 m) M M. cymindicus, right view (near Ukulele Camp, 1210–1365 m) N M. cymindulus, right view, sac everted (Kīpahulu, 1960 m).

Identification

(n = 5). The eyes are moderately developed—ocular ratio = 1.41–1.46, ocular lobe ratio = 0.75–0.81—with the ocular lobe smoothly joined to the gena. The pronotal front angles are broadly protruded, subangulate externally, with the anteriorly broad pronotal lateral marginal depression narrowed to the position of the lateral seta, and then broadened toward the back of the pronotum. The elytral striae are present across the width of the elytra, depth of striae 6 and 7 subequal to slightly shallower than striae 1–5 and 8. The discal elytral intervals are only slightly convex, with very fine punctures in the associated striae. The metepisternum bears ~16 punctures in 2–3 rows, about twice as many punctures as seen in M. consanguineus. Cuticular microsculpture is essentially identical to that observed in M. consanguineus: 1, vertex with transverse mesh, sculpticell breadth 2× length; 2, pronotal disc with transverse mesh, sculpticell breadth 2–3× length; 3, pronotal base with distinct isodiametric and transverse sculpticells; 4, elytral disc with transverse mesh, sculpticell breadth 3–4× length; and 5, elytral apex with transverse mesh, sculpticell breadth 3× length, to transverse lines.

Male genitalia (n = 6). Aedeagal median lobe gracile with broad, trapezoidal apex, distance from parameral articulation to tip 4.1× median breadth (Fig. 29G), apex with flat ventral and apical faces, the tip angulate; median lobe nearly straight in ventral view, the right margin concave, and left margin incurved before the apparently rounded tip (Fig. 29H); internal sac broad, parallel sided, with moderate dorsal microtrichial patch and smaller ventral microtrichical patch that is near base of sac (Fig. 29E–F); flagellar plate well sclerotized, length 0.42× distance from parameral articulation to tip.

Female reproductive tract (n = 1). Bursa copulatrix columnar with rounded apex, length 1.32 mm, breadth 0.46 mm, base as broad as vagina (Fig. 30B); bursal walls translucent with thick wrinkles; gonocoxite 1 with 4 apical fringe setae, 6–7 smaller setae on medial surface (Fig. 31B); gonocoxite 2 narrowly subtriangular with subacuminate apex, base narrowly extended laterally, 2 lateral ensiform setae with apical seta broader, apical nematiform setae on medioventral surface at 0.73× gonocoxite length.

Types

For Mecyclothorax cognatus Sharp holotype female (BMNH) labeled: Mecyclothorax cognatus Type D.S. Haleakala Perkins 111 // Type // Hawaiian Is. Perkins 1904-336. // Haleakala Maui 5000 ft. Perkins IV 1894 // Atelothorax optatus Sharp compared with type E.B.B. // HOLOTYPE Mecyclothorax cognatus Sharp J.K. Liebherr 1998 (black-margined red label). For Atelothorax optatus Sharp holotype male (BPBM) platen mounted and labeled: Atelothorax / optatus / Type / D.S. / Haleakala / 1902 (written on obverse of mounting card) // Mecyclothorax / cognatus Sharp / Compared / with type E.B.B. // HSPA # / 1960 // HOLOTYPE / Atelothorax / optatus / Sharp / J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat

M. cognatus is restricted to forests in the Waikamoi region (Fig. 32) from 1200–1850 m elevation. The only recorded Perkins lot (No. 111) was collected iv–1894 near Ukulele Camp, with modern collections centered on the Ukulele Pipeline Koa-‘Ōhi‘a Mesic Forest at ~1500 m elevation northeast of the Ukulele Camp site. Beetles occur on and under bark of koa, in moss on trunks of ‘ōhi‘a, and on the ground in the leaf litter or under logs. Several have been collected in yellow-pan traps set on the ground.

Mecyclothorax anchisteus sp. n.

Figs 32, 33A

Diagnosis

This species is easily diagnosed by the distinctly cordate pronotum, MPW/BPW = 1.57, with glabrous hind angles. The pronotal lateral margins are distinctly convergent anterad the acute and acuminately projected hind angles (Fig. 33A). The head, pronotum, and elytra are a uniformly dark rufous. The eyes are moderately convex, ocular ratio = 1.43, but rather small, covering only ¾ of the little protruded ocular lobe; ocular lobe ratio = 0.76. The elytra are broadly subovoid, with the humeri narrowly rounded; MEW/HuW = 2.0. The discal elytral intervals are covered with irregular transverse-line microsculpture, the lines not joined into a mesh. Setal formula 2 1 2 1[sae]. Standardized body length 5.1 mm.

Description

(n = 1). Head capsule with frontal grooves broad near clypeus, a lateral carina to anterior supraorbital seta; dorsal surface of neck slightly concave; labral anterior margin broadly, shallowly emarginate, antennae filiform, sparse pelage of short setae present on antennomeres 2–3; mentum tooth with sides acute, apex tightly rounded. Pronotum moderately transverse, MPW/PL = 1.26; median base depressed relative to disc, with small punctures and lateral wrinkles; basal margin straight, slightly indented posterad laterobasal depressions; median longitudinal impression shallow, very finely incised at depth; anterior transverse impression very shallow, narrow, crossed medially by longitudinal wrinkles; anterior callosity nearly flat, crossed by indistinct wrinkles; front angles slightly projected, tightly rounded; anterior width greater than basal width, APW/BPW = 1.07; lateral marginal depression narrow throughout, margin upturned to finely beaded before sinuation; laterobasal depression smooth, laterally elevated to projected lateral margin. Proepisternum with smooth hind marginal groove; prosternal process medially depressed, a broad lateral marginal bead that is narrowed anteriorly. Elytra with convex disc, sides depressed; basal groove slightly recurved to broadly rounded humeral angle; parascutellar seta present; parascutellar striole continuous, with 4–5 punctures; sutural interval more convex than intervals 2–4, sutural juncture upraised; sutural and 2nd striae of subequal depth from base to apex; striae 1–8 complete, stria 7 slightly shallower, associated intervals moderately convex; discal striae with slightly irregular punctulae basally, smooth and deep apically; 7th and 8th intervals of similar convexity mesad subapical sinuation; 2 dorsal elytral setae at 0.27× and 0.49–0.52× elytral length; setal impressions extended over 2/3 width of interval 3; subapical seta present, apical seta absent; lateral elytral setae arranged in anterior series of 7 setae and posterior series 6 setae; elytral marginal depression narrow throughout, margin slightly upraised at humerus; subapical sinuation shallow, broad. Mesepisternum with ~5 punctures in 1 row; metepisternal width to length ratio = 0.81; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1–5; suture between ventrites 2 and 3 complete; apical ventrite of female with 4 equally spaced marginal setae and a median trapezoid of 4 setae, the basal pair longer. Legs-metatarsomere 1/metatibial length ratio = 0.22; metatarsomere 4 length along outer lobe 1.37× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci very broad, median area rough to carinate. Microsculpture of vertex with isodiametric to slightly stretched isodiametric sculpticells in transverse rows; pronotal disc with transverse mesh, sculpticell breadth 3–4× length; pronotal median base with isodiametric to transverse sculpticells; elytral disc with irregular transverse lines, apex with more regular transverse lines; metasternum with distinct transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of antennomere 1 flavous, antennomeres 2–3 rufoflavous, 4–11 rufobrunneous; proepipleuron and proepisternum rufobrunneous; elytral apex paler than disc, rufoflavous to position of subapical seta; elytral epipleuron rufoflavous laterally, rufobrunneous ventrally, metepisternum rufobrunneous; abdomen medially rufobrunneous, laterally rufoflavous; abdominal apical ventrite 6 with apical 1/3 paler, flavous; metafemur flavous with piceous cloud covering basal half; metatibia rufoflavous with brunneous cast.

Female reproductive tract. The lone female holotype was not dissected.

Holotype

Female (NMNH) labeled: HI:Maui Haleakala N.P. / Kipahulu Vy. West Camp / 20-V-1998 lot01 1950 m / el. pyrethrum fog mossy / ohia D.A. Polhemus // HOLOTYPE / Mecyclothorax / anchisteus / Sharp / J.K. Liebherr 2015 (black-margined red label).

Etymology

The species epithet anchisteus is Greek for next of kin (Jaeger 1955), signifying this species’ close affinities to M. cognatus, M. affinis, and M. consanguineus.

Distribution and habitat

This species is known from a single specimen collected at the head of Kīpahulu Valley (Fig. 32) after application of pyrethrin fog to a mossy ‘ōhi‘a tree.

Mecyclothorax consanguineus sp. n.

Figs 30C, 31C, 33B, 34A–I, 35

Diagnosis

Of species in this group characterized by broader, shorter elytra and a basally constricted, quadrisetose pronotum (Figs 28B–C, 33B), this species can be diagnosed by the narrowed humeri, MEW/HuW = 1.91–2.04. As in the morphologically similar and partially sympatric M. cognatus, the pronotum is moderately constricted basally—MPW/BPW = 1.37–1.60—and the discal elytral striae are finely impressed and lined with minute punctures, the associated intervals slightly convex. The male aedeagal median lobe configuration is unique in the mucronate apex (Fig. 34A–I). Setal formula 2 2(1) 2 2; the basal pronotal seta may be unilaterally present, though at least one seta was observed in all examined specimens. Standardized body length 4.1–5.3 mm.

Description

(n = 5). Head capsule with frontal grooves broad near clypeus, a lateral carina to anterior supraorbital seta; dorsal surface of neck flat to slightly concave; eyes moderately developed, ocular ratio = 1.39–1.51, ocular lobe ratio = 0.72–0.77; labral anterior margin with subangulate emargination, excavated 0.2× length medially; antennae filiform, antennomeres 2-3 with sparse pelage of short setae; mentum tooth with sides acute, apex tightly rounded. Pronotum moderately narrow, MPW/PL = 1.15–1.25, and moderately to rather constricted basally, MPW/BPW = 1.37–1.60; hind angle right to slightly acute, projected, the lateral margin convergent to parallel just anterad the angle; median base very depressed relative to disc, shallow longitudinal wrinkles and small punctures covering surface; basal margin straight medially, slightly indented posterad laterobasal depressions; median longitudinal impression very shallow, indistinct; anterior transverse impression very shallow, broad, crossed by longitudinal wrinkles; anterior callosity nearly flat with wrinkles on the posterior half; front angles projected, tightly rounded; front and basal pronotal angles variably subequal, APW/BPW = 0.92–1.03; lateral marginal depression slightly broader at front angle, moderately narrow behind, edge upturned; laterobasal depression smooth with median extension from disc as a tubercle. Proepisternum with 6 punctures along hind marginal groove; prosternal process medially depressed, with broad lateral marginal bead. Elytra with moderately narrow humeri, the disc convex and side moderately sloped; basal groove slightly recurved to hitched humeral angle at base of elytral lateral depression; parascutellar seta present; parascutellar striole shallow, smooth anteriorly with 3 punctures in posterior portion; sutural interval equally convex as intervals 2–4 basally, more convex apically; sutural and 2nd striae of subequal depth from base to apex; sutural stria finely impressed, irregularly punctate basally, smooth and deep apically, striae 2–5 with minute punctulae on disc, striae slightly irregular along length; 7th and 8th interval of similar convexity mesad subapical sinuation; two dorsal elytral setae at 0.26–0.28× and 0.54–0.56× elytral length, setal impressions small, extended over ½ width of interval 3; apical and subapical setae present; lateral elytral setae arranged as an anterior series of 7 setae, a posterior series of 6 setae; elytral marginal depression moderately broad at humerus, gradually narrowed to beadlike margin at subapical sinuation; subapical sinuation shallow, nearly obsolete. Mesepisternum with ~8–9 punctures in 1–2 rows; metepisternal width to length ratio = 0.84; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1–5; suture between ventrites 2 and 3 complete; apical ventrite of male with 2 marginal setae, apical ventrite of female with 4 equally spaced marginal setae plus a median trapezoid of 4 smaller, subequal setae. Legs-metatarsomere 1/metatibial length ratio = 0.21; metatarsomere 4 length along outer lobe 1.4× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci deep, broad, median area strigose to carinate. Microsculpture of vertex a transverse mesh, sculpticell breadth 2× length; pronotal disc with reduced transverse mesh, sculpticell breadth 2–3× length; pronotal median base with distinct isodiametric and transverse sculpticells; elytral disc with transverse mesh, sculpticell breadth 3–4× length; elytral apex with transverse mesh, sculpticell breadth 3× length, to transverse lines; metasternum with distinct transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous; antennomere 1 flavous, antennomeres 2–3 rufoflavous, 4–11 rufobrunneous; pronotal disc rufobrunneous, pronotal apical and lateral margins rufoflavous; proepipleuron rufoflavous, proepisternum rufobrunneous; elytral disc rufobrunneous, sutural interval concolorous to rufoflavous basally, rufoflavous to flavous apically; elytral marginal depression concolorous with disc to paler, rufoflavous basally, apex slightly paler, rufoflavous to position of subapical seta; elytral epipleuron and metepisternum rufobrunneous; abdomen with ventrites medially rufopiceous, ventrites 3–6 rufoflavous laterally; abdominal apical ventrite with apical half paler, flavous; metafemur flavous; metatibia rufobrunneous.

Male genitalia (n = 15). Aedeagal median lobe distinctly curved, variably robust, with ratio of distance from parameral articulation to tip versus depth at midlength ranging 3.1–4.2 (Fig. 34A, H), but always with apex narrowly extended well beyond ostial opening, and tip denticulate; a brief indentation along apicoventral surface (Fig. 34A–B, D–I); median lobe straight in ventral view, right margin slightly concave, left margin incurved before apparently blunt tip (Fig. 34C); internal sac generally lightly spiculated, but with indistinct ventral microtrichial patch comprised of slightly larger microtrichia (Fig. 34A); flagellar plate relatively large, length 0.45× distance from parameral articulation to tip.

Female reproductive tract (n = 1). Bursa copulatrix columnar with apex rounded, bursa narrowed apically, length 1.05 mm, apical breadth 0.29 mm, basal breadth 0.36 mm equal to vagina breadth (Fig. 30C); bursal walls translucent with thick wrinkles; gonocoxite 1 with 3–4 apical fringe setae and 6–7 small setae on medial surface (Fig. 31C); gonocoxite 2 narrowly subtriangular with broad apex, base broadly extended laterally, 2 lateral ensiform setae with apical seta broader and longer, apical nematiform setae on medioventral surface at 0.74× gonocoxite length.

Holotype

Male (CUIC) labeled: HI: Maui Haleakala NW / slope Waikamoi Pres. / trans. 3 @ 1700 m el. / 10-IV-1991 sifting / litter J.K. Liebherr // HOLOTYPE / Mecyclothorax / consanguineus / Liebherr / J.K. Liebherr 2015 (black-margined red label).

Paratypes

261 specimens (see Appendix).

Etymology

The Latin adjectival consanguineus means related by blood, or kindred (Brown 1956), and signifies this species’ close relationship to the previous three species.

Distribution and habitat

M. consanguineus has an elevationally broad windward distribution that spans the Waikamoi Koa-‘Ōhi‘a Mesic Forest to the lower elevation ‘Ōhi‘a-‘Ōlapa Wet Forest, and then disjunctly extends through the Hāna Bogs to the head of Kīpahulu Valley (Fig. 35). Collection localities range 1210–2438 m elevation. A population is known from the western wall of Ke‘anae Valley, 1325 m elevation. Another marginal population occurs at Paliku, 1830 m elevation, in the eastern end of Haleakalā Crater where windward fog and moisture spill over the headwall of Kīpahulu Valley creating a lens of mesic habitat. Beetles occur in forests composed of varying mixtures of koa and ‘ōhi‘a, as well as more open, higher elevation habitats including Dubautia (kupaoa) and Leptecophylla (pūkiawe). That the species can occur in such open habitats begs the question of why it has not been recorded from the Hanawī face of Haleakalā, an area of open koa Forest with extensive Dicranopteris (uluhe) fern understory. However our sampling of the Hanawī Koa-Uluhe Formation was very cursory, leaving the question for a more intensive biotic survey.

Figure 35.

Recorded geographic distribution of M. consanguineus.

Mecyclothorax aeneus Sharp

Figs 30D, 31D, 33C, 36

Mecyclothorax aeneus Sharp 1903: 255; Britton 1948b: 164.

Diagnosis

The narrow body and moderately convex elytral intervals with nearly smooth striae set this species apart. Individuals of this species can be diagnosed by the narrow pronotum–MPW/PL = 1.15–1.19–with its lateral margins convergent for 0.1× the pronotal length anterad the acute, projected hind angles (Fig. 33C). The elytra are narrowly ellipsoid, with distinctly recurved basal grooves leading to proximate, subangulate humeri; MEW/HuW = 2.04–2.15. The elytral disc is rufobrunneous, with a cupreous reflection enhanced by a distinct granulate isodiametric mesh. At the elytral apex, the 8th interval is more convex than the fused apical portion of intervals 5 + 7. Setal formula 2 2 2 2. Standardized body length 5.7–5.8 mm for specimens available to the author, though Britton (1948b) listed the size range as 4.8–5.8 mm.

Identification

(n = 2). The eyes are moderately convex, ocular ratio = 1.42, covering ¾ of the protruded ocular lobe, ocular lobe ratio = 0.76. There is a deep carinate groove at the juncture of lobe and gena. The pronotal median base is depressed relative to the disc, and irregularly covered with fine punctures, longitudinal wrinkles lining the juncture of base and disc. The pronotal anterior transverse impression is shallow and broad, not incised, and crossed by dense, deep longitudinal wrinkles that extend across the anterior callosity. The pronotal laterobasal depressions are broad and smooth, with a well-developed median tubercle. The mesepisternum bears ~16 punctures in 2–3 rows. Microsculpture is well developed, with the vertex covered by an isodiametric mesh in transverse rows, and the pronotal base covered with mixture of granulate isodiametric and transverse sculpticells.

Female reproductive tract (n = 1). Bursa copulatrix columnar with rounded apex, length 1.14 mm, breadth 0.39 mm, base as broad as vagina (Fig. 30D); bursal walls translucent with thick wrinkles in basal half, more transparent and little wrinkled apically; gonocoxite 1 with 3–4 apical fringe setae and 8–9 small setae on medial surface (Fig. 31D); gonocoxite 2 narrowly subtriangular with broad apex, tightly rounded tip, 2 lateral ensiform setae with apical seta broader and longer, apical nematiform setae on medioventral surface at 0.72× gonocoxite length.

Lectotype

Male (BMNH) hereby designated, labeled: Thriscothorax aeneus D.S. Type Haleakala Perkins 383 // Type // Hawaiian Is. Perkins 1904-336 // LECTOTYPE Mecyclothorax aeneus Sharp J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat

M. aeneus is a species of the mesic Waikamoi forests (Fig. 36). In 1894 Perkins collected two specimens near the leeward forest edge at Ukulele Camp, with two more recently collected specimens from 1700–1850 m elevation in the Honomanu drainage complementing the original type series. The two recent collections were made from moss and humus adhering to ‘ōhi‘a trunks.

Figure 36.

Recorded geographic distributions of M. robustus group species.

Mecyclothorax antaeus sp. n.

Figs 30E, 33D, 34J–L, 36, 37A

Diagnosis

This species can be diagnosed by the broad elytra with sides subparallel at midlength (Fig. 33D), a configuration shared with M. robustus and M. haydeni (Fig. 38C–E), however the discal elytral striae are smooth to only minutely punctate instead of distinctly punctate, and the associated intervals are only moderately convex instead of convex. The pronotum has the lateral margin parallel to slightly convergent anterad the right hind angles, and the pronotal median base is covered with fine punctures. Beetles of the other two species have pronota with parallel to divergent basal lateral margins. The male aedeagal median lobe of M. antaeus males has the apex elongate and parallel sided with a downturned tip (Fig. 34J–K), versus the apically flattened median lobe of M. robustus (Fig. 41) and the elongate, evenly curved apex observed in males of M. haydeni (Fig. 43). Setal formula 2 2 2 2. Standardized body length 4.6–5.9 mm.

Description

(n = 5). Head capsule with frontal grooves broad near clypeus, a lateral carina to anterior supraorbital seta; dorsal surface of neck flat to slightly concave; eyes moderately convex, ocular ratio = 1.46–1.50, ocular lobe distinctly protruded from gena, ocular lobe ratio = 0.71–0.78, an abruptly depressed slot at juncture of lobe and gena; labral anterior margin broadly shallowly emarginate; antennae filiform, antennomeres 2–3 with sparse pelage of short setae; mentum tooth with sides acute, apex tightly rounded. Pronotum subcordate, quadrate to slightly transverse, MPW/BPW = 1.38–1.45, MPW/PL = 1.18–1.25; hind angle right, projected, the margin behind convex; basal margin slightly convex between hind angles; median longitudinal impression shallow, finely incised; anterior transverse impression broad, shallow, crossed by longitudinal wrinkles, lined with granulate isodiametric microsculpture; anterior callosity slightly elevated, covered with dense longitudinal wrinkles, strigose; front angles slightly projected, rounded; base broader than distance between front angles, APW/BPW = 0.86–0.98; lateral marginal depression moderately broad, explanate, edge upturned; laterobasal depression broad, smooth, with median tubercle. Proepisternum with 6 indistinct punctures along hind marginal groove; prosternal process medially depressed, with broad lateral marginal bead. Elytra subquadrate, humeri moderately narrow, rounded, sides subparallel at midlength; elytral disc convex, sides progressively sloped laterally; basal groove recurved to subangulate humeri, the lateral margin upraised, and humeral angle defined by hitch at base of lateral marginal depression, MEW/HuW = 2.02–2.13; parascutellar seta present; parascutellar striole deep with 5 punctures; sutural interval more convex than intervals 2–4, sutural juncture upraised; sutural and 2nd striae of subequal depth from base to apex; sutural and lateral discal striae 2–6 minutely punctate, striae slightly irregular along length; 7th and 8th intervals of similar convexity mesad subapical sinuation; 2 dorsal elytral setae at 0.29–0.34× and 0.55–0.60× elytral length, setal impressions small, extended over ½ width of interval 3; apical and subapical setae present; lateral elytral setae arranged in an anterior series of 7(6) setae and a posterior series of 6 setae; elytral marginal depression moderately broad in anterior half, narrowed anterad subapical sinuation; subapical sinuation shallow, broad. Mesepisternum with ~14 punctures in 2–3 rows; metepisternal width to length ratio = 0.81; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1–5; suture between ventrites 2 and 3 complete; apical ventrite of male with 2 marginal setae, apical ventrite of female with 4 equally spaced setae and median patch of 4(5) short, subequal setae. Legs-metatarsomere 1/metatibial length ratio = 0.20; metatarsomere 4 length along outer lobe 1.33× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci deep, broad, median area strigose to carinate. Microsculpture of vertex an isodiametric mesh; pronotal disc with transverse mesh, sculpticell breadth 2–3× length; pronotal median base with distinct to granulate isodiametric mesh; elytral disc and apex with transverse mesh, sculpticell breadth 3× length, to transverse lines; metasternum with distinct transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous with a purplish reflection; antennomere 1 flavous, 2–3 rufoflavous, 4–11 rufobrunneous; pronotal disc rufobrunneous with purplish reflection; pronotal margins rufoflavous inside front angles, otherwise concolorous with disc; proepipleuron rufoflavous, proepisternum rufobrunneous; elytral disc rufobrunneous with purplish reflection; sutural interval concolorous with disc basally, rufoflavous apically; elytral lateral marginal depression rufoflavous, apex slightly paler than disc, rufoflavous to position of subapical seta; elytral epipleuron rufoflavous laterally, rufobrunneous ventrally, metepisternum rufobrunneous; abdomen with ventrites medially rufobrunneous, marginally rufoflavous; apical half of ventrite 6 paler, flavous; metafemur flavous; metatibia rufoflavous.

Male genitalia (n = 4). Aedeagal median lobe gracile, distance from parameral articulation to tip 4.1× depth at midlength (Fig. 34J–K), apex narrowly extended beyond ostial opening, tip downturned with flat apical face; median lobe broadly curved rightward in ventral view, the apex parallel sided and tip blunt (Fig. 34L); internal sac tubular, elongate, with two ventral microtrichial patches, a larger basal patch and a smaller apical patch situated just distad a median constriction (Fig. 34J); flagellar plate of moderate size, length of sclerotized internal face 0.38× distance from parameral articulation to tip.

Female reproductive tract (n = 1). Bursa copulatrix columnar with rounded apex, bursa narrower in apical half, length 1.10 mm, apical breadth 0.32 mm, basal breadth 0.51 mm, broader than width of vagina (Fig. 30E); bursal walls translucent basally with think wrinkles, apical surface shagreened but not wrinkled; gonocoxite 1 with 3–4 apical fringe setae and 6–9 smaller setae on medial surface (Fig. 37A); gonocoxite 2 narrowly subtriangular with subacuminate apex, base extended laterally as a thin extension, 2 lateral ensiform setae, the apical seta slightly broader, apical nematiform setae on medioventral surface at 0.74× gonocoxite length.

Figure 37.

Left female gonocoxa, M. robustus group species, ventral view. A M. antaeus (Kīpahulu west rim, 1850 m) B M. cymindicus (Ukulele Camp Pipeline, 1525 m) C M. cymindulus (Kīpahulu, 1950 m) D M. robustus (Waikamoi, 1310 m) E M. haydeni (Kīpahulu, 1500).

Holotype

Male (CUIC) labeled: HI: Maui / Haleakala N.P. / Kipahulu west rim ESE / Kuiki sift humus ex ohia 15-V-1993 lot 03 / el. 1850 m // J.K. Liebherr & / A.C. Medeiros / Collectors // HOLOTYPE / Mecyclothorax / antaeus / Liebherr / J.K. Liebherr 2015 (black-margined red label).

Paratypes

39 paratype specimens plus 1 non-type specimen (see Appendix).

Etymology

Antaeus was a “giant Libyan wrestler whose strength was renewed when he touched the earth (Brown 1956),” an apt epithet for this close relative of M. robustus. The name is treated as a noun.

Distribution and habitat

M. antaeus is a species of the Manawainui Planeze, with known collection localities lining the western rim of Kīpahulu Valley (Fig. 36) at 1200–2145 m elevation. Specimens have been collected in association with ‘ōhi‘a, either from humus around tree bases, or from humus on tree trunks.

Mecyclothorax cymindicus Sharp

Figs 30F, 34M, 37B, 38A, 40

Mecyclothorax cymindicus Sharp 1903: 248; Britton 1948b: 164.

Diagnosis

Along with M. cymindulus, the smallest-bodied beetles in the group (Fig. 38A–B) excepting the smallest individuals of M. antaeus (Fig. 33D); standardized body length for this species 4.1–4.7 mm. This and M. cymindulus are also the most narrow-bodied species, with subquadrate elytra and subangulate, laterally extended humeri (Figs 38A–B). This species deviates from M. cymindulus by the distinctly punctate discal elytral striae, the punctures in basal portions of striae 1–5 expanding strial breadth, and by the less transverse microsculpture; The elytral sutural interval is covered with isodiametric microsculpture, with the lateral intervals bearing a transverse mesh, sculpticell breadth 3–4× length, versus the transverse mesh on the sutural interval and transverse lines laterally observed in individuals of M. cymindulus. The eyes also tend to be more convex in this species—ocular ratio = 1.41–1.45—versus the ocular ratio = 1.34–1.43 of M. cymindulus. Setal formula 2 2 2 2.

Figure 38.

Mecyclothorax robustus group species, dorsal habitus view. A M. cymindicus (Ukulele Camp Pipeline, 1525 m) B M. cymindulus (Kīpahulu, 1950 m) C M. robustus (Ke‘anae, 1325 m) D M. robustus (Waikamoi, 1170 m). E M. haydeni (Helele‘ike‘oha, 1615 m).

Identification

(n = 5). The pronotum is little transverse, MPW/PL = 1.17–1.22, and the pronotal hind angles are acute and moderately projected, with the pronotal lateral margins slightly convergent anterad the angles; MPW/BPW = 1.36–1.54. The elytral humeral angles are defined by a hitch in the recurved basal groove at its juncture with the lateral marginal depression; MEW/HuW = 1.83–1.95. The vertex is covered with a transverse mesh, sculpticell breadth 2× length; pronotal disc with transverse mesh, sculpticell breadth 3–4× length, and pronotal base with distinct isodiametric sculpticells medially and a transverse mesh laterally.

Male genitalia (n = 1). Aedeagal median lobe gracile, distance from parameral articulation to tip 3.6× depth at midlength (Fig. 34M); apex moderately extended beyond ostial opening, apical face flat, tip rounded at juncture of apical face and ventral margin; internal sac with sclerotized dorsal microtrichial patch (based on distal position in uneverted specimen); flagellar plate length 0.47× parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix columnar with rounded apex, length 1.03 mm, breadth 0.29 mm (Fig. 30F); bursal walls translucent, thickly wrinkled; gonocoxite 1 with 4 apical fringe setae and 7 smaller setae on medial surface (Fig. 37B); gonocoxite 2 narrowly subtriangular with broad apex, tip tightly rounded, 2 lateral ensiform setae, the apical seta broader and longer, apical nematiform setae on medioventral surface at 0.77× gonocoxite length.

Lectotype

Female (BMNH) hereby designated, labeled: Mecyclothorax cymindicus Type D.S. Haleakala Perkins 680 // Type // Hawaiian Is. Perkins 1904-336 // LECTOTYPE Mecyclothorax cymindicus Sharp J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat

M. cymindicus is geographically restricted to the Waikamoi area (Fig. 40), with localities ranging 1210–1740 m elevation. Perkins’ collections were made in the vicinity of Ukukule Camp along the then leeward edge of the Koa-‘Ōhi‘a Mesic Forest, with more recent records from the Honomanu drainage to the east and Waikamoi Gulch from 1210–1435 m elevation. Specimens have been recorded in association with ‘ōhi‘a trunks, logs, or leaf litter, and Cibotium (hāpu‘u).

Mecyclothorax cymindulus sp. n.

Figs 34N, 37C, 38B, 39A, 40

Diagnosis

Differing from its most similar species group member M. cymindicus (Fig. 38A–B) by: 1, pronotal hind angles obtuse due to rounded basal margin posterad angle, the pronotal lateral margin subparallel anterad angle; 2, broad, minutely punctate discal elytral striae over basal half of length; 3, elytra with transverse-mesh microsculpture on the sutural interval, and parallel-lined microsculpture laterally on disc and at apex. If a male is available, the aedeagal median lobe of M. cymindulus has a more flattened apex with a subangulate, ventrally angled tip (Fig. 34N), versus the more rounded apex with ventrally expanded tip of male M. cymindicus (Fig. 34 M). Setal formula 2 2 2 2. Standardized body length 4.1–4.6 mm.

Description

(n = 5). Head capsule with frontal grooves straight, a lateral carina to anterior supraorbital seta; dorsal surface of neck flat to slightly concave; ocular lobe moderately extended from gena, eyes not covering posterior portion of lobe, ocular ratio = 1.34–1.41, ocular lobe ratio = 0.70–0.76; labral anterior margin subangulately excavated medially to 0.2× length; antennae broader in apical half, submoniliform, antennomeres 2–3 with sparse pelage of short setae; mentum tooth with sides acute, apex tightly rounded. Pronotum moderately transverse, MPW/PL = 1.21–1.25, base broad, MPW/BPW = 1.41–1.49; median base depressed relative to disc, covered with irregular punctures and longitudinal wrinkles; basal margin slightly convex between laterobasal depressions; median longitudinal impression shallow, very finely incised at depth; anterior transverse impression very shallow, broad, crossed by fine longitudinal wrinkles; anterior callosity slightly convex, crossed by numerous wrinkles; front angles not projected, rounded; anterior and basal widths subequal, APW/BPW = 0.95–1.04; lateral marginal depression broader, beaded at front angle, evenly expanded along midlength, moderately broad and upturned toward basal angle; laterobasal depression smooth, broad, with or without convex median extension from disc. Proepisternum with 6 punctures along hind marginal groove; prosternal process medially depressed, a broad marginal bead laterally. Elytra with convex disc, sides more sloped; basal groove straight from sutural stria laterally to subangulate humeri; elytral slightly narrowed basally, subquadrate, MEW/HuW = 1.83–1.95; parascutellar seta present; parascutellar striole with 4–5 punctures, continuous between punctures; sutural interval more convex than lateral intervals; sutural and 2nd striae of subequal depth from base to apex; discal striae 1–5 and base of 6 minutely punctate, striae slightly irregular, associated intervals slightly convex; 7th and 8th interval of similar convexity mesad subapical sinuation; 2 dorsal elytral setae at 0. 25–0.27× and 0.57–0.59× elytral length, setal impressions extended over 2/3 width of interval 3; apical and subapical setae present; lateral elytral setae arranged as anterior series of 7 setae, posterior series of 6 setae; elytral marginal depression broadest at humerus, gradually narrowed to a beadlike margin at subapical sinuation; subapical sinuation shallow, abruptly incurved anteriorly. Mesepisternum with ~10 punctures in 2 rows; metepisternal width to length ratio = 0.79; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1–5; suture between ventrites 2 and 3 reduced, effaced laterally; apical male ventrite with 2 marginal setae, apical female ventrite with 4 equally spaced marginal setae and a median trapezoid of 4 subequally short setae. Legs-metatarsomere 1/metatibial length ratio = 0.17; metatarsomere 4 length along outer lobe 1.35× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci deep, broad, basal tarsomeres medially carinate. Microsculpture of vertex transverse, sculpticell breadth 2× length; pronotal disc with transverse mesh, sculpticell breadth 3–4× length; pronotal median base with distinct isodiametric and transverse sculpticells; metasternum with distinct transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous; antennomeres 1–3 flavous, 4–11 rufobrunneous; pronotal disc rufobrunneous, pronotal margins slightly paler; proepipleuron and proepisternum rufoflavous; elytral disc rufobrunneous, metallic reflection present due to microsculpture; sutural interval rufous basally, flavous apically; elytral marginal depression narrowly flavous, apex flavous to juncture of intervals 3 and 4; elytral epipleuron flavous, metepisternum rufoflavous; abdomen with ventrites 1–6 medially rufoflavous, laterally flavous, ventrite 6 with apical half flavous; metafemur flavous; metatibia rufoflavous.

Male genitalia (n = 1). Aedeagal median lobe gracile, distance from parameral articulation to tip 4.0× depth at midlength (Fig. 34N); apex moderately extended beyond ostial opening, apical face flat, tip distinctly angulate at juncture of apical face and ventral margin; internal sac with lightly sclerotized dorsal microtrichial patch, and ventral face covered with fine spicules; flagellar plate length 0.47× parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix columnar with rounded apex, narrowed along midlength, length 0.93 mm, medial breadth 0.31 mm, basal breadth at vagina 0.43 mm (Fig. 39A); bursal walls translucent with thin wrinkles; gonocoxite 1 with 2–3 apical fringe setae and 6–7 smaller setae on medial surface (Fig. 37C); gonocoxite 2 narrowly subtriangular with broad apex, tip tightly rounded, 1–2 lateral ensiform setae, apical nematiform setae on medioventral surface at 0.76× gonocoxite length.

Figure 39.

Female bursa copulatrix and associated reproductive structures, M. robustus group species, ventral view (for abbreviations see Table 2, p. 23). A M. cymindulus (Kīpahulu, 1950 m) B M. robustus (Waikamoi, 1310 m) C M. haydeni (Kīpahulu, 1500 m). Scale bar = 0.50 mm.

Holotype

Female (BPBM) labeled: Kipahulu Valley / Maui Camp 1 / 945 m, 6–12.VIII.67 // N. Wilson / Collector / BISHOP // ? cymindicus (E.C.Z. handwriting) // HOLOTYPE / Mecyclothorax / cymindulus / Liebherr / J.K. Liebherr 2015 (black-margined red label).

Paratypes

HI: Maui: Haleakala N.P., Kipahulu Vy., sift litter, 1500 m el., 09-v-1991 lot 03, Jessel/Medeiros (CUIC, 1), Mauka Ridge, pyrethrin fog Metrosideros/moss, 2055 m el., 21-v-1998 lot 01, Polhemus (NMNH, 1), West Camp, pyrethrin fog Metrosideros/moss, 1960 m el., 20-v-1998 lot 01, Polhemus (CUIC, 1; NMNH, 2).

Etymology

This epithet is taken from the Latin noun cymindis, meaning night hawk, modified with the diminutive ending -ule. Beetles of this species are the same size as those of M. cymindicus, but use of the common stem for the epithet is meant to connote the two species’ affinities; a convention used by Perrault (1984, 1986, 1988, 1989) to deal with the rampant Mecyclothorax diversity of Tahiti.

Distribution and habitat

Beetles of M. cymindulus are recorded only from Kīpahulu Valley, 945–2055 m elevations (Fig. 40). They have been discovered in sifted leaf litter or on mossy ‘ōhi‘a trunks.

Figure 40.

Recorded geographic distributions of M. robustus group species.

Mecyclothorax robustus (Blackburn)

Figs 37D, 38C–D, 39B, 41, 42

Cyclothorax robustus Blackburn 1881: 228; Blackburn and Sharp 1885: 215.

Thriscothorax robustus, Sharp 1903: 268; Swezey 1954: 7 (koa associate).

Mecyclothorax robustus, Britton 1948b: 166.

Mecyclothorax robustus Sharp 1903: 255.

Mecyclothorax robustus, Britton 1948b: 166 (synonymy).

Diagnosis

This and M. haydeni represent the two larger bodied species in this group with subquadrate elytra, the discal elytral striae lined with distinct, round punctures (Figs 38C–E). Of the two species, the discal elytral striae are more distinctly and regularly punctate in M. robustus, though this characteristic is variable. In aggregate, individuals of M. robustus have larger eyes, ocular ratio = 1.48–1.54, that cover most of the ocular lobe, ocular lobe ratio = 0.76–0.84, in contrast to beetles of M. haydeni with ocular ratio = 1.41–1.49, and ocular lobe ratio = 0.70–0.78. Male genitalia are diagnostic, with the aedeagal median lobe of M. robustus males exhibiting an apex with a flattened apical surface and tightly rounded, ventrally directed tip (Fig. 41), versus a median lobe with an evenly downcurved and narrowed apex for M. haydeni (Fig. 43). Setal formula 2 2 2 2. Standardized body length 4.8–6.1 mm.

Figure 41.

Male aedeagus, M. robustus (for abbreviations see Table 2, p. 23). A–C (Ukulele Camp Pipeline, 1495 m). A Right view B Right view, sac everted C Ventral view D–E (Ko‘olau Gap, 1325 m) D Right view E Right view, sac everted F–H (Kuhiwa, 1590 m) F Right view G Right view, sac everted H Ventral view.

Identification

(n = 5). In keeping with the larger eyes, the posterior portion of the ocular lobe joins the gena at nearly a right angle in this species, with a shallow groove at the juncture of lobe and gena. The pronotal median base is covered with distinct punctures, and longitudinal wrinkles line the juncture with the disc; the anterior transverse impression is deep, narrow, and crossed by deep wrinkles, its posterior surface lined with isodiametric microsculpture. The pronotum is variably transverse, MPW/PL = 1.20–1.28, with variably moderate basal constriction, MPW/BPW = 1.34–1.50. The parascutellar striole is distinctly 5-punctate, and striae 1–6 are distinctly punctate basally, and slightly irregular to smooth apically. The elytral disc is rufobrunneous, often with a purplish reflection due to the transverse-mesh to transverse-line microsculpture covering the intervals.

Male genitalia (n = 36). Aedeagal median lobe gracile, distance from parameral articulation to tip varies 3.5–4.8× depth at midlength (Fig. 41B, F); apex moderately extended beyond ostial opening, but always with apical face flat and tip rounded at juncture of apical face and ventral margin; median lobe slightly curved rightward in ventral view, the curvature of left margin more exaggerated in more robust aedeagi (e.g., Fig. 41C versus 41H, which is same specimen as 41F); internal sac parallel sided, dorsal and ventral microtrichial patches variably developed (Fig. 41B, E, G); flagellar plate moderately large, length of sclerotized ventral face 0.44–0.48× parameral articulation-tip distance.

Female reproductive tract (n = 2). Bursa copulatrix columnar with expanded apex, length 1.25–1.28 mm, breadth 0.48–0.51 mm, basal breadth 0.34 mm in one specimen (Fig. 39B), basal breadth subequal to apical breadth in second specimen; bursal walls translucent with thick wrinkles; gonocoxite 1 with 2–3 apical fringe setae and 7–10 smaller setae on medial surface (Fig. 37D); gonocoxite 2 narrowly subtriangular with subacuminate apex, base narrowly extended laterally, 2 lateral ensiform setae with apical seta broader and longer, apical nematiform setae on medioventral surface at 0.74× gonocoxite length.

Types

For Cyclothorax robustus Blackburn, holotype female (BMNH) labeled: mounting platen with Blackburn Maui code (Zimmerman 1957: 210), Cyc robustus (on reverse) // Type // Rev. T. Blackburn 1888-30. // HOLOTYPE Cyclothorax robustus Blackburn J.K. Liebherr 1998 (black-margined red label). For Mecyclothorax robustus Sharp, lectotype male (BMNH) labeled: Mecyclothorax robustus D.S. Type Haleakala Perkins 622 // Type // Hawaiian Is. Perkins 1904-336 // LECTOTYPE Mecyclothorax robustus Sharp J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat

The distributions of M. robustus and M. haydeni subdivide the windward face of Haleakalā, with this species found from Kuhiwa Valley on the east to the leeward forest edge near Makawao on the west (Fig. 42) at elevations spanning 1137–1830 m. Historical Perkins records can be predominantly assigned to Ukulele Camp (Perkins 1894, 1896a, b). The species is distributed in ‘Ōhi‘a and Koa Forest formations, though most direct associations involve beetles being found in moss on ‘ōhi‘a, and secondarily on hāpu‘u (Cibotium) or on ‘ōhi‘a nurse logs. This is an abundant species within its habitats. Beetles can be beaten from vegetation at night, or found under boards or logs either during day or at night.

Figure 42.

Recorded geographic distributions of M. robustus group species.

Mecyclothorax haydeni sp. n.

Figs 37E, 38E, 39C, 42, 43

Diagnosis

Larger bodied beetles within the species group, standardized body length = 5.0–6.2 mm, with broad, subquadrate elytra. The discal elytral striae are lined with small though distinct punctures that at most expand strial breadth, or at least introduce irregularities to the strial orientation (Fig. 38E). The eyes are smaller than those observed in M. robustus individuals (see diagnosis above), though the male genitalic configuration is the only certain means to diagnose the two species. The male median lobe of M. haydeni males exhibits an evenly downcurved apex (Fig. 43), though the degree of narrowing toward the tip and extension beyond the ostial opening varies among individuals (Fig. 43B versus 43D). The male aedeagal internal sac is shorter and narrower in males of M. haydeni (Fig. 43B, F, H) than in males of M. robustus (Fig. 41B, E, G). Setal formula 2 2 2 2.

Figure 43.

Male aedeagus, M. haydeni (for abbreviations see Table 2, p. 23). A–C (Helele‘ike‘oha, 1615 m). A Right view B Right view, sac everted C Ventral view. D–G (Kīpahulu, 1845-1960 m) D–E Right view F Right view, sac everted G Ventral view. H Right view, sac everted (Kaumakani, 1127 m).

Description

(n = 5). Head capsule with frontal grooves broad near clypeus, with broad lateral carina to anterior supraorbital seta; dorsal surface of neck flat to slightly concave; labral anterior margin subangulate, medially excavated 0.1× length; antennae robustly filiform, antennomeres 2–3 with sparse pelage of short setae; mentum tooth with sides acute, apex tightly rounded. Pronotum slightly transverse, MPW/PL = 1.20–1.24, variably constricted basally, MPW/BPW = 1.37–1.50; hind angle slightly obtuse, basal margin rounded posterad angle, lateral margin slightly divergent anterad hind angle; median base depressed relative to disc, covered with dense punctures and wrinkles, surface strigose; basal margin broadly, moderately convex between laterobasal depressions; median longitudinal impression very shallow, finely incised; anterior transverse impression broad, shallow, crossed by wrinkles and lined by granulate isodiametric microsculpture; anterior callosity slightly elevated, crossed by dense longitudinal wrinkles, strigose; front angles slightly projected, rounded; pronotum broader basally than apically, APW/BPW = 0.90–0.95; lateral marginal depression only slightly broader at front angle, moderately narrow, edge upturned; laterobasal depression broad, smooth, with median tubercle. Proepisternum with 6 indistinct punctures along hind marginal groove; prosternal process medially depressed, with broad lateral marginal bead. Elytra subquadrate, disc convex, sides more sloped; basal groove recurved to subangulate humerus, the angle defined by hitch in groove at juncture with lateral marginal depression, MEW/HuW = 1.81–2.08; parascutellar seta present; parascutellar striole continuous, with 5 small punctures or irregularities along length; sutural interval more convex than lateral intervals, sutural juncture upraised; sutural and 2nd striae of subequal depth from base to apex; discal striae minutely punctured in basal 1/3, smooth and deep apically, associated intervals convex; 7th and 8th intervals of similar convexity mesad subapical sinuation; 2 dorsal elytral setae at 0.31× and 0.63× elytral length, setal impressions small, extended over ½ width of interval 3; apical and subapical setae present; lateral elytral setae arranged as anterior series of 7 setae and posterior series of 6 setae; elytral marginal depression moderately narrow throughout length, flat bottomed until subapical sinuation; subapical sinuation evident, moderately deep. Mesepisternum with ~ 14 punctures in two rows; metepisternal width to length ratio = 0.79; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1–5; suture between ventrites 2 and 3 complete; apical male ventrite with 2 marginal setae, and apical female ventrite with 4 equally spaced setae and a median trapezoid of 4 subequal, short setae. Legs-metatarsomere 1/metatibial length ratio = 0.19; metatarsomere 4 length along outer lobe 1.4× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci deep, broad, median area medially strigose. Microsculpture of vertex an isodiametric mesh; pronotal disc with transverse mesh, sculpticell breadth 2–3× length; pronotal median base with distinct to granulate isodiametric mesh; elytral disc and apex with transverse mesh, sculpticell breadth 3× length, to transverse lines unconnected into a mesh, the apex with more transverse lines; metasternum with distinct transverse mesh; laterobasal abdominal ventrites swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous; antennomere 1 flavous, 2–3 rufoflavous, 4–11 rufobrunneous; pronotal disc rufobrunneous, margins and apex slightly paler, base concolorous; proepipleuron rufoflavous, proepisternum rufobrunneous; elytral disc rufobrunneous; sutural interval rufous basally, rufoflavous apically; elytral marginal depression slightly paler, elytral apex concolorous with disc; elytral epipleuron rufoflavous, metepisternum rufobrunneous; abdomen with ventrites 1–6 medially rufobrunneous, laterally rufoflavous; apical abdominal ventrite 6 with apical half paler, flavous; metafemur flavous; metatibia rufoflavous.

Male genitalia (n = 26). Aedeagal median lobe slender, elongate, distance from parameral articulation to tip 4.1–5.5× depth at midlength (Fig. 43E, H), but apical extension always smoothly curved relative to median lobe shaft, the apex evenly narrowed to a rounded tip; median lobe broadly curved rightward, the apex blunt in ventral view (Fig. 43C, G); internal sac of variable length (Fig. 43B, F, H), with consistent presence of two ventral microtrichial patches—basal and apical as in M. antaeus (Fig. 34J)—the apical patch of variable size; flagellar plate relatively small, length of sclerotized ventral face 0.33–0.36× parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix columnar with narrow, rounded apex, length 1.17 mm, apical breadth 0.31 mm, basal breadth 0.47 mm subequal to vagina breadth (Fig. 39C); bursal walls translucent with thin wrinkles basally, apical surface shagreened but not wrinkled; gonocoxite 1 with 2–4 apical fringe setae, a moderately sized seta just basad medioapical angle and 7–8 small setae on medial surface (Fig. 37E); gonocoxite 2 narrowly subtriangular with broad apex and tightly rounded tip, 2 lateral ensiform setae, apical nematiform setae on medioventral surface at 0.78× gonocoxite length.

Holotype

Female (BPBM) labeled: Kipahulu Valley / Maui Camp 2 / 1250 m, 13-17.VIII.67 // N. Wilson / Collector / BISHOP // ? cognatus (E.C.Z. handwriting) // HOLOTYPE / Mecyclothorax / haydeni / Liebherr / J.K. Liebherr 2015 (black-margined red label).

Paratypes

176 specimens (see Appendix).

Etymology

This species is named to honor the contributions of Dr. James E. Hayden, Jr. to this project, wherein he dissected numerous male specimens of Hawaiian Mecyclothorax in order to delineate species boundaries.

Distribution and habitat

Mecyclothorax haydeni occupies ‘Ōhi‘a Forest formations from 1127–2145 m elevation on the wetter, eastern end of the Haleakalā windward forest (Fig. 42). Beetles may be found in leaf litter via sifting, or they may be observed actively running on tree trunks and ferns at night. To date, equivalent samples derived from leaf litter sampling or pyrethrin fogging at 1500–1960 m in Kīpahulu Valley include many more individuals of this species than do samples from 1200 m elevation.

Mecyclothorax interruptus species group

Diagnosis. Specimens representing this species group can be diagnosed by the fully developed, impunctate elytral striae from suture to lateral margin, with adjacent striae at least connected by the depressions surrounding the dorsal elytral setae—M. bradycelloides (Fig. 44B)—or more tortuously distorted and variously anastomosed along their length (Figs 44A, C, E, 49A–C). Setal formulae for the Haleakalā species vary, including 2 2 2 2, 2 1(2) 2 2, 2 1 3 2, or the infraspecifically variable formula of 2 1 2 (0-1(2)) in M. arthuri.

Membership and distribution. This group is restricted to Maui Nui, with four species distributed in West Moloka‘i (Liebherr 2007), and two in West Maui (Liebherr 2011) complementing the nine Haleakalā species. Liebherr (2007), following Britton (1948b), placed M. perkinsi (Sharp) in the M. constrictus species group based on the basally constricted prothorax with glabrous hind angles (setal formula 2 1 2-3 1[ae]). Male M. perkinsi exhibit a unique accessory apical aedeagal projection (Liebherr 2007, fig. 95) not seen in any other Mecyclothorax species, though male M. constrictus (Sharp) exhibit an anatomically similar accessory subapical aedeagal projection (Liebherr 2007, fig. 97). Nevertheless, M. perkinsi exhibits tortuously anastomosing elytral striae as seen in species of this group; the only other Hawaiian species not placed in the M. interruptus group to exhibit this condition (Liebherr 2007, fig. 30). These conflicting character-based data suggest that current placement of this species should be revisited pending additional information.

Key to adults of the Mecyclothorax interruptus species group, Haleakalā volcano, Maui, Hawai‘i

1 Adjacent elytral striae not conjoined—though they may approach (Fig. 44A)—except in close association with a dorsal elytral seta, in which instance the impression surrounding seta will connect striae 2 and 3 (Fig. 44B) 2
1’ Adjacent elytral striae variously conjoined along their length not in close association with a dorsal elytral seta, these fusions variously involving striae 1 and 2, 3 and 4, or 5 and 6 (Figs 44C, E, 49, 50) 3
2(1) Pronotum broad, MEW/MPW = 1.30–1.32 (Fig. 44A); standardized body length = 5.2–5.3 mm (027) M. integer Sharp
2’ Pronotum narrow, MEW/MPW = 1.47 (Fig. 44B); standardized body length = 4.1 mm (028) M. bradycelloides sp. n.
3(1) Vertex, pronotum, elytra and ventral surface concolorous, brunneous to piceous, legs paler, femora pale brunneous to flavous at midlength (Figs 44E, 49, 50) 4
3’ Vertex iridescent piceous, contrasted to flavous pronotum and elytral disc, though elytra with melanic areas associated with strial fusions (Fig. 44C), thoracic ventrites and mediobasal area of abdominal venter piceous versus flavous abdominal apex (Fig. 44D) (029) M. irregularis Britton
4(3) Body broader, brunneous to dark brunneous, legs paler, femora may be darker but not markedly so (Figs 49, 50); striae 3 and 4 irregularly fused near dorsal elytral setae, striae 5 and 6 may also be fused 5
4’ Body narrow, piceous, legs paler, base color flavous though tibiae distinctly, contrastedly piceous (Fig. 44E); elytral striation unstable, bases of striae 5 and 6 often fused or approaching resulting in varying convexity of associated intervals, otherwise striae generally independent along length (030) M. anthracinus sp. n.
5(4) Elytral striae intensely anastomosed, bulbous calli asymmetrically formed from fusions of all striae (Fig. 49A–C) 6
5’ Fusion of elytral striae limited to anastomosed striae 3 and 4 near dorsal elytral setae, and possibly striae 5 and 6 basally 7
6(5) Elytra narrower relative to pronotal width, MEW/MPW = 1.47 (Figs 49A–B); pronotal disc with granulate isodiametric microsculpture, deep lateral plaquelike depressions complement deep median longitudinal impression (031) M. arthuri sp. n.
6’ Elytra broader relative to pronotal width, MEW/MPW = 1.63–1.67 (Fig. 49C); pronotal disc with shallow transverse-mesh microsculpture, surface glossy (032) M. medeirosi sp. n.
7(5) Pronotum broad, MPW/BPW = 1.35–1.47, maximum elytral width: maximum pronotal width = 1.34–1.45; standardized body length 4.8–5.9 mm 8
7’ Pronotum narrower, more constricted basally, MPW/BPW = 1.49–1.53, MEW/MPW = 1.45–1.49; standardized body length 3.7–4.0 mm (033) M. inconscriptus sp. n.
8(7) Pronotal disc with distinct isodiametric sculpticells arranged in transverse rows, surface coriaceous; male aedeagal median lobe with acuminate dorsal expansion (Fig. 45M–N) (034) M. foveolatus sp. n.
8’ Pronotal disc with swirling transverse-mesh microsculpture, sculpticell breadth 2–3× length; male aedeagal median lobe apex with bluntly rounded dorsal expansion (Fig. 45O–P) (035) M. interruptus Sharp

Mecyclothorax integer Sharp, stat. n.

Figs 44A, 45A, 48

Mecyclothorax interruptus var. integer Sharp 1903: 252; Britton 1948b: 163.

Diagnosis

This is the broadest-bodied species in the Haleakalā Mecyclothorax fauna, exhibiting a large prothorax and broadly subquadrate elytra, MEW/MPW = 1.30–1.32 (Fig. 44A). The pronotal lateral margins are only slightly sinuate anterad the obtuse-rounded hind angles; and the linear laterobasal depression is separated from the pronotal lateral margin by a broad tubercle. The elytral striae are nearly regular, though striae 2 and 3 may approach unilaterally. The dorsal elytral setal impressions are foveate anteriorly, crossing interval 3 at the anterior seta, and smaller posteriorly, impressing half the interval width at the posterior seta. The dorsal body coloration is uniformly rufobrunneous, with the legs paler, rufoflavous. Setal formula 2 2 2 2. Standardized body length 5.2–5.3 mm.

Figure 44.

Mecyclothorax interruptus group species, dorsal habitus view. A M. integer (Olinda, 1210 m) B M. bradycelloides (Ukulele Camp Pipeline, 1465–1495 m) C–D M. irregularis (Polipoli, 1738 m) C Dorsal view D Ventral view E M. anthracinus (Kuhiwa, 2070-2100 m).

Identification

(n = 3). The eyes are moderately convex, ocular ratio = 1.43–1.46, but cover much of the ocular lobe, ocular lobe ratio = 0.80–0.84. The pronotum is large, MPW/PL = 1.28–1.31, and modestly constricted basally, MPW/BPW = 1.36–1.40. The elytral disc is flat medially, sides moderately sloped, and the subangulate humeri are defined by juncture of the slightly recurved basal groove and lateral marginal depression. The discal elytral intervals, including the sutural interval, are moderately convex. The vertex is covered with isodiametric microsculpture, the sculpticells transversely stretched on the neck, pronotal disc with distinct transverse mesh, the base glossy in parts with an elongate transverse mesh; elytral disc covered with elongate transverse mesh, a loose transverse mesh and parallel lines on the elytral apex; metasternum covered with an obsolete transverse mesh.

Male genitalia (n = 1). Aedeagal median lobe slender, distance from parameral articulation to tip 5.6× depth at midlength; shaft slightly curved basally, straight to slightly recurved apically, the apex broadly rounded with blunt dorsal projection (Fig. 45A); internal sac without evident ornamentation.

Figure 45.

Male aedeagus, M. interruptus group species (for abbreviations see Table 2, p. 23). A M. integer, right view (Olinda, 1210 m). B–C M. bradycelloides, right and ventral views (Ukulele Camp Pipeline, 1465-1495 m) D–E M. irregularis, right and ventral views (Polipoli, 1738 m) F–G M. anthracinus, right and ventral views (Kuhiwa, 2070-2100 m) H–J M. arthuri, Right, left, and ventral views, sac everted (ESE Kuiki, 2145 m) K–L M. inconscriptus, right and ventral views (Kaupō Gap, 1495 m) M–N M. foveolatus, right and ventral views (Kuhiwa, 880 m) O–P M. interruptus, right and ventral views (Olinda, 1210–1365 m).

Lectotype

Male (BPBM) hereby designated, dissected and labeled: 622 (on reverse of mounting platen) // Haleakala / Maui 6000 ft. / Perkins V 1896 // M. interruptus / var. integer Sharp / [number OK but date / on label possibly wrong → as Oct. 1896 in orig. / description / SYNTYPE / G/A. Samuelson det. 196 // LECTOTYPE ♂ / Mecyclothorax / interruptus var. / integer Sharp / J.K. Liebherr 2011 (black-margined red label).

Paralectotype

Female (BPBM) labeled: M. interruptus / var. integer / Haleakala / Perkins (on obverse of mounting platen), 680. (on reverse of mounting platen) // Hawaiian Is. / R.C.L. Perkins // Sharp Coll / 1905-313. // PARALECTOTYPE ♀ / (same labelling as Lectotype).

Distribution

M. integer is known only from the lectotype and paralectotype collected by Perkins in his lots 622 and 680; “Haleakala 4000 ft., v-1896”, and “Haleakala 4000+ ft., x-1896” (Anonymous N D), respectively (Fig. 48). Of the October visit, Perkins (1896b) wrote: “In October 1896 I camped for a considerable time at about 5,000 ft. on Haleakala and did a good deal of work at various points Eastward in the windward forest entering this at various points from the upper edge towards the forest that lies above Wailua (p. 1).” This locality would lie about 200 ft. elevation below the Ukulele Camp (site) of the USGS (1983) Kilohana, Hawaii quadrangle. Recent collections near this site did not result in rediscovery of this species.

Mecyclothorax bradycelloides sp. n.

Figs 44B, 45B–C, 48

Diagnosis

This species (Fig. 44B), M. anthracinus (Fig. 44E), and M. inconscriptus (Fig. 50A) represent the three smallest-bodied species in this group, with all individuals equal to or less than 4.1 mm length. Of these, M. bradycelloides is the only species without fused elytral striae, though the impressions of the dorsal elytral setae are large, crossing most of the width of interval 3. The pronotum is also the most constricted basally, with MPW/BPW = 1.56 versus a collective span of 1.42–1.53 for the other two species. The elytral margins are straight and nearly parallel at elytral midlength, though the tightly rounded humeral angles are narrowly separated relative to elytral width due to the broadly rounded elytral margins laterad the angles; MEW/HuW = 2.0. Setal formula 2 2 2 2. Standardized body length 4.1 mm.

Description

(n = 1). Head capsule with frontal grooves deep and broad near clypeus, narrowed toward anterior supraorbital seta; dorsal surface of neck slightly convex; ocular ratio = 1.49, ocular lobe ratio = 0.81; antennae filiform, antennomere 3 with sparse pelage of short setae; mentum tooth with sides acute, apex tightly rounded. Pronotum cordate, hind angle obtuse, rounded behind; lateral margin sinuate for short distance anterad hind angle; median base covered with punctures and wrinkles isolated by granulate microsculpture; basal margin nearly straight, slightly convex medially; median longitudinal impression shallow, finely incised; anterior transverse impression deeply incised, complete, crossed by longitudinal wrinkles; anterior callosity broadly, slightly convex; front angles projected, tightly rounded, APW/BPW = 1.07; lateral marginal depression narrow, edge upturned to beaded; laterobasal depression broad, irregular, slightly convex medially. Proepisternum with smooth hind marginal groove; prosternal process medially depressed, with lateral marginal bead. Elytra subquadrate, disc slightly convex; parascutellar seta present on left side, absent on right; parascutellar striole shallow with 6 punctures; sutural interval moderately convex, appearing broader than intervals 2–4 due to elevated juncture at suture; sutural and 2nd striae of subequal depth from base to apex; discal striae with small punctures that cause strial irregularities along length, intervals convex; 7th and 8th intervals of similar convexity mesad subapical sinuation; 2 dorsal elytral setae at 0.23–0.27× and 0.60–0.63× elytral length; apical and subapical setae present; lateral elytral setae arranged as anterior series of 7 setae, and posterior series of 4–5 setae; elytral marginal depression moderately broad, lined with sculpticells, margin upturned; subapical sinuation very shallow, broad. Mesepisternum with ~9 shallow punctures in 1–2 rows; metepisternal width to length ratio = 0.81; metepisternum/metepimeron suture distinct. Abdomen with nearly smooth ventrites; suture between ventrites 2 and 3 complete; apical male ventrite with 2 marginal setae. Legs-metatarsomere 1/metatibial length ratio = 0.17; metatarsomere 4 length along outer lobe 1.2× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci broad, deep, median area carinate. Microsculpture of vertex isodiametric sculpticells arranged in transverse rows; pronotal disc with transverse mesh, the microsculpture parallel in part; pronotal median base with granulate isodiametric sculpticells; elytral disc with irregular elongate transverse mesh and parallel lines; elytral apex with upraised transverse mesh; metasternum with indistinct transverse mesh; laterobasal abdominal ventrites with indistinct transverse mesh. Coloration of vertex rufobrunneous; antennomeres 1–3 flavous, 4–11 rufobrunneous; pronotal disc rufobrunneous, margins narrowly paler, rufoflavous; proepipleuron flavous, proepisternum brunneous; elytral disc rufobrunneous, sutural interval concolorous basally, rufoflavous apically, margins narrowly rufoflavous in lateral depression, apex broadly flavous; elytral epipleuron flavous with rufous cast, metepisternum rufobrunneous; abdominal ventrites 1–5 rufobrunneous, 6 basally rufoflavous, flavous in apical half; metafemur flavous; metatibia flavous with brunneous cast.

Male genitalia (n = 1). Aedeagal median lobe robust, distance from parameral articulation to tip 3× depth at midlength (Fig. 45B); apex narrowly extended twice its depth beyond ostial opening, tip subangulate where flattened apical face and ventral margin meet; median lobe straight in ventral view, the left margin distinctly incurved to meet blunt tip (Fig. 45C); internal sac with well-developed, heavily sclerotized dorsal ostial microtrichial patch (based on position near apex of ostium (Fig. 45B), and separate ventral ostial microtrichial patch (Fig. 45C); flagellar plate well sclerotized, visible just inside dorsal margin of lobe (Fig. 45B).

Holotype

Male (NMNH) dissected and labeled: HI:Maui Haleakala / Waikamoi N.C.P. Ukulele / Pipeline 7-V-1998 lot07 / 1465-1495m el. / pyrethrum fog mossy ohia / log D.A. Polhemus // HOLOTYPE / Mecyclothorax / bradycelloides / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Etymology

The adjectival epithet bradycelloides is based on Moloka‘i’s Mecyclothorax bradycellinus Sharp, with the -oides suffix signifying the similarity between the two species.

Distribution and habitat

The type locality for M. bradycelloides lies at ~1500 m elevation near Ukulele Camp (Site) of the USGS (1983) Kilohana, Hawaii quadrangle (Fig. 48). This species was found in a pyrethrin fog sample of a mossy ‘ōhi‘a log.

Mecyclothorax irregularis Britton

Figs 44C–D, 45D–E, 46A, 47A, 48

Cyclothorax multipunctatus, Blackburn 1878a: 122 (misidentification).

Mecyclothorax irregularis Britton 1948b: 161; Liebherr 2005b, 122.

Diagnosis

The irregularly anastomosed elytral striae 2–6, combined with the bicolored dorsal surface—piceous head, testaceous pronotum, plus testaceous elytral convexities versus piceous striae (Fig. 44C)—uniquely diagnose this species within the Hawaiian Mecyclothorax fauna. The ventral body coloration is equally distinctive, with the piceous genae, thoracic ventrites, metacoxae, and mediobasal portions of the basal abdominal ventrites distinctly contrasted to the pale mentum and gula, pronotal and elytral epipleura, and abdominal apex (Fig. 44D). Setal formula 2 2 2 2. Standardized body length 4.7–5.2 mm.

Identification

(n = 5). The head is broader relative to the hindbody in this species, MEW/MHW = 1.78–1.90, than in any other species of the group. The broad head is based on a broad head capsule as the eyes are small, ocular lobe ratio = 0.70–0.81, and not very convex, ocular ratio = 1.30–1.39. The pronotal median base is smooth, with the small punctures isolated by areas of granulate isodiametric microsculpture. The laterobasal pronotal depressions are also smooth, shallow, with a broad median tubercle. Microsculpture across the body is well developed, with: 1, vertex, and pronotal disc and base with granulate isodiametric sculpticells, the surface appearing dull; 2, elytral disc and apex with isodiametric sculpticells; 3, metasternum covered with an upraised transverse mesh; and 4, basal abdominal ventrites with lateral areas covered with swirling isodiametric and transverse sculpticells.

Male genitalia (n = 1). Aedeagal median lobe slender, distance from parameral articulation to tip 4.8× depth at midlength (Fig. 45D); shaft curved basally, nearly straight apically, apex slightly expanded dorsoventrally with rounded tip; median lobe straight in ventral view, left margin distinct incurved to blunt apex, right margin angled leftward to tip (Fig. 45E); internal sac without distinct ornamentation, but surface covered with melanic spicules, short flagellar plate evident in repose, length 0.24× parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix columnar with rounded apex, length 0.68 mm, breadth 0.23 mm (Fig. 46A); bursal walls translucent, densely wrinkled; gonocoxite 1 with 3 apical fringe setae, and 6–7 smaller setae on medial surface (Fig. 47A); gonocoxite 2 subtriangular, apex acuminate, base evenly extended laterally from lateral margin, 2 lateral ensiform setae with the apical seta longer and broader, apical nematiform setae on medial surface at 0.73× gonocoxite length.

Figure 46.

Female bursa copulatrix and associated reproductive structures, M. interruptus group species, ventral view (for abbreviations see Table 2, p. 23). A M. irregularis (Polipoli, 1738 m) B M. anthracinus (Kuhiwa, 2070–2100 m) C M. arthuri (ESE Kuiki, 2145 m) D M. inconscriptus (Kaupō Gap, 1495 m). E M. foveolatus (Kopili‘ula, 1127 m) F M. interruptus (Waikamoi, 1310 m). Scale bar = 0.50 mm.

Figure 47.

Left female gonocoxa, M. interruptus group species, ventral view. A M. irregularis (Polipoli, 1738 m) B M. anthracinus (Kuhiwa, 2070–2100 m) C M. arthuri (ESE Kuiki, 2145 m) D M. inconscriptus (Kaupō Gap, 1495 m) E M. foveolatus (Kopili‘ula, 1127 m) F M. interruptus (Waikamoi, 1310 m).

Holotype

Female (BMNH) labeled: mounting platen with Blackburn Maui code (Zimmerman 1957: 210), multip (on reverse) // Type // Hawaiian Is. Rev. T. Blackburn 1883-30 // Cyclothorax irregularis sp. n. E.B. Britton det. 1939.

Distribution and habitat

This species was described by Britton (1948b) from a single Blackburn specimen originally considered by Blackburn to represent M. multipunctatus. The type locality for M. multipunctatus was listed as “Haleakala, 4000 ft.”; i.e. near Olinda. The only modern records derive from the ecologically disjunct forest near Polipoli Springs on Haleakalā’s southwest rift (Fig. 48). Microhabitats at Polipoli where this species has been collected include Dryopteris wallichiana (laukahi) fern litter, deep leaf litter at the bottom of a small rocky face, and the mossy surface of a small, downed Pinus radiata trunk lying in deep leaf litter at the bottom of a shallow ravine.

Figure 48.

Recorded geographic distributions of M. interruptus group species.

Mecyclothorax anthracinus sp. n.

Figs 44E, 45F–G, 46B, 47B, 48

Diagnosis

The small, dark-bodied beetles that comprise this species look ever so like small bits of anthracite coal, their dorsal body surface a reflective black (Fig. 44E). Also, this is the only species in the group that is characterized by absence of the parascutellar seta. The pronotum is narrow and basally constricted, MPW/PL = 1.18–1.24, MPW/BPW = 1.42–1.50, the disc covered with well-developed transverse wrinkles. The elytral intervals are convex and striation irregular, with striae 5 and 6 fused near the basal groove, and the dorsal setal impressions foveate and of diameter equal to the width of interval 3, these impressions associated with longitudinal irregularities of striae 2 and 3. The femora are flavous apically and covered with a piceous cast over their basal third; tibiae piceous. Setal formula 2 2 2 2. Standardized body length 3.6–4.0.

Description

(n = 5). Head capsule with frontal grooves deep near clypeus, straight with external carina to anterior supraorbital seta; dorsal surface of neck convex, eyes moderately convex, ocular ratio = 1.42–1.50, ocular lobe ratio 0.77–0.85; labral anterior margin broadly, shallowly emarginate, antennae filiform, antennomere 3 with sparse pelage of short setae; mentum tooth with orthogonal sides, apex pointed. Pronotum with lateral margin subparallel to convergent anterad right to acute hind angle; median base depressed relative to disc, covered with rugose wrinkles; basal margin nearly straight, slightly convex medially; median longitudinal impression shallow, finely incised, crossed by wrinkles; anterior transverse impression broad, evident, bordered anteriorly by slightly convex anterior callosity that is crossed by fine wrinkles; front angles slightly projected, rounded; anterior width subequal to broader than basal width, APW/BPW = 1.00–1.06; lateral marginal depression moderately narrow, edge upturned to beaded; laterobasal depression broad, depressed with wrinkled surface. Proepisternum with 6 minute punctures along hind marginal groove; prosternal process medially depressed, without marginal bead. Elytra subellipsoid, disc flat, sides moderately sloped; basal groove slightly recurved to tightly rounded humeral angle; humeri narrow, MEW/HuW = 2.06–2.10; parascutellar striole finely incised, continuous; sutural interval moderately convex, slightly more upraised than intervals 2–4; sutural and 2nd striae of subequal depth from base to apex; discal striae 1–8 complete and deep to apex, smooth with minute irregularities along striae suggesting punctulae; 7th and 8th intervals of similar convexity mesad subapical sinuation; 2 dorsal elytral setae at 0.32× and 0.65–0.73× elytral length; apical and subapical setae present; lateral elytral setae arranged in anterior series of 7 setae and posterior series of 4(5) setae; elytral marginal depression narrow, edge upturned; subapical sinuation very shallow, nearly obsolete. Mesepisternum with 8 shallow punctures in 2 rows; metepisternal width to length ratio = 0.71; metepisternum/metepimeron suture distinct, metathoracic flight wing an ovoid flap, length 2.5× breadth, with reduced R and M veins, the flap extended 2/3 distance to hind margin of metanotum. Abdomen with indistinct lateral wrinkles on ventrites 1–3; suture between ventrites 2 and 3 complete; apical male ventrite with 2 marginal setae, apical female ventrite with 4 equally spaced marginal setae and a median trapezoid of 4, subequal short setae. Legs-metatarsomere 1/metatibial length ratio = 0.17; metatarsomere 4 length along outer lobe 1.2× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci broad, shallow. Microsculpture of vertex of granulate isodiametric sculpticells; pronotal disc covered with distinct transverse mesh, median base with granulate isodiametric sculpticells; elytral disc covered with well-developed transverse mesh, apex with well-developed isodiametric mesh in transverse rows; metasternum with upraised transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex granulate rufopiceous; antennomere 1 flavous, antennomeres 2–3 with piceous cast, 4–11 piceous; pronotal disc granulate rufopiceous, margins narrowly paler, rufobrunneous; proepipleuron rufobrunneous with piceous upper margin, proepisternum rufobrunneous with piceous cast; elytral disc rufopiceous, sutural interval paler, dark rufous throughout, margins narrowly paler basally, concolorous with disc apically; elytral epipleuron rufobrunneous, metepisternum rufopiceous; abdomen rufopiceous across width of ventrites 1–5, apical ventrite 6 with apical 1/3 paler, rufobrunneous.

Male genitalia (n = 1). Aedeagal median lobe curved, gracile, distance from parameral articulation to tip 4× depth at midlength (Fig. 45F); apex angularly narrowed to tightly rounded tip formed at juncture of flat apical face and ventral margin; median lobe sinuously recurved left then right in ventral view (Fig. 45G), tip tightly rounded; internal sac with apparent dorsal ostial microtrichial patch (based on uneverted specimen; Fig. 45F), sac surface covered with microspicules; flagellar plate evident just inside dorsal margin of median lobe.

Female reproductive tract (n = 1). Bursa copulatrix a narrow digitiform lobe attached to broader vagina, lobe length 0.26 mm, lobe apical breadth 0.10 mm, vagina breadth 0.25 mm (Fig. 46B); bursal walls thin, transparent; gonocoxite 1 with 3 apical fringe setae and 5–6 smaller setae on medial surface (Fig. 47B); gonocoxite 2 falcate, narrow apically with base broadly extended laterally, 2 lateral ensiform setae with apical seta broader and longer, apical nematiform setae on medial surface at 0.75× gonocoxite length.

Holotype

Female (BPBM) labeled: NW 6000´-6500', / Haleakala / VIII-18-37 Maui // Beating // ECZimmerman / Collector // 3 // HOLOTYPE / Mecyclothorax / anthracinus / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes

HI: Maui: Haleakala N.P., NW upper slope, beating 1830–1980 m el., 18-viii-1937, Zimmerman (BPBM, 2); Koolau For. Res., Hanawi N.A.R., Frisbee Meadow Camp, woods below, sift litter Dubautia/tree, 2072–2099 m el., 19-v-1993 lot 01, Liebherr/Medeiros (CUIC, 6).

Etymology

The shiny coal black color of the dorsal surface of these beetles begs for use of the Latin adjective anthracinus.

Distribution and habitat

M. anthracinus is known from two isolated, high-elevation localities near the upper limits of the windward forest. E.C. Zimmerman beat three specimens from vegetation at 1830–1980 m elevation along the NW upper slope, and six specimens were taken from leaf litter samples of Dubautia reticulata litter at “Frisbee Meadow Camp” in the headwaters of Hanawī Stream to the east (Fig. 48). Whether the unusual coal-black color and ridged dorsal body surface of M. anthracinus beetles serve to enhance crypsis on the dark, fissured bark of the tree Dubautia seems a question worthy of study.

Mecyclothorax arthuri sp. n.

Figs 45H–J, 46C, 47C, 49A–B, 51

Diagnosis

This species can be diagnosed by the narrow pronotum relative to the elytra, MEW/MPW = 1.64–1.67, and the irregularly anastomosing striae 2–7, resulting in massive convex warts that may or may not be bilaterally symmetrical (Fig. 49A–B). These characters set this species apart from all others from Haleakalā except M. medeirosi below. That species differs by a relatively broader pronotum (Fig. 49C); MEW/MPW = 1.47. A third species, M. oppenheimeri Liebherr from West Maui, shares the warty elytral condition of M. arthuri and M. medeirosi while exhibiting a pronotum of relative width intermediate to that of those two species; i.e. MEW/MPW = 1.52–1.57 (Liebherr 2011, fig. 36). Setal formula: 2 1 2 0(1-2)[sae]. The variation in the apical elytral setae is distributed as: 5 individuals with both setae absent; 1 individual with apical seta absent and subapical setae present; and 1 individual with both apical and subapical setae present. Standardized body length 4.0–4.4 mm.

Figure 49.

Mecyclothorax interruptus group species, habitus view. A–B M. arthuri (ESE Kuiki, 2145m). A Female specimen B Male specimen C–D M. medeirosi (New Greensword Bog, 1850 m) C Dorsal view D Ventral view.

Description

(n = 5). Head capsule with frontal grooves deep near clypeus, straight, with external carina; dorsal surface of neck flat to convex; eyes moderately convex, ocular ratio = 1.43–1.47, covering ¾ of slightly protruded ocular lobe, ocular lobe ratio = 0.72–0.80; labral anterior margin broadly, moderately deeply emarginate; antennae filiform, antennomeres 2–3 with sparse pelage of short setae; mentum tooth with sides acute, apex rounded. Pronotum bisetose, lateral seta present, basal seta absent, basally constricted, MPW/BPW = 1.46–1.53; hind angle acute, apex acuminate, lateral margin broadly convergent anterad angle; median base depressed relative to disc, with sparsely distributed punctures near basal margin, longitudinal wrinkles at juncture with disc; basal margin straight between laterobasal depressions; median longitudinal impression shallow, indistinct, to deep, distinct, always crossed by transverse wrinkles emanating onto disc; anterior transverse impression deeply incised, complete, short wrinkles extended from impression posteriorly onto disc; anterior callosity broadly convex, smooth; front angles slightly produced, tightly rounded; width between front angles greater than basal width, APW/BPW = 1.01–1.08; lateral marginal depression narrow, edge beaded; laterobasal depression broad, a depressed expansion of lateral depression. Proepisternum with 6 minute punctures along hind marginal groove; prosternal process medially depressed, with broad marginal bead. Elytra broadly subquadrate, lateral margins convex from humerus to subapical sinuation; basal groove incrementally recurved, bordering 4 basal convexities mesad tightly rounded to subangulate humeral angle; humeri narrow relative to broadest portion of elytra behind midlength; MEW/HuW = 2.07–2.16; parascutellar seta present; parascutellar striole narrow, deep, directly connected to isolated basal portion of sutural stria; sutural interval as convex as interval 2, though less convex than warty protuberances associated with intervals 3–7; discal striae lined with sculpticells, smooth; sutural and 2nd striae of subequal depth in apical half of elytra; discal striae 2–6 joined irregularly at positions of dorsal elytral setae, larger convexities associated with striae 2–4, smaller more irregular convexities laterad; warty convexities vary among individuals, as well as bilaterally (Fig. 49A–B); 7th and 8th interval of similar convexity mesad subapical sinuation; 2 dorsal elytral setae at 0.31× and 0.69× elytral length, setal impressions very small, shallow, not distinctly associated with a depressed stria; lateral elytral setae arranged in anterior series of 5 setae, an isolated intermediate seta, and 4 posterior setae; elytral marginal depression broad laterally, narrow behind; subapical sinuation shallow, broad. Mesepisternum with 8 shallow punctures in 2 rows; metepisternal width to length ratio = 0.72; metepisternum/metepimeron suture distinct; metathoracic flight wing an ovoid flap 3.3× long as broad, remnant R and M veins present, flap extended to hind margin of metanotum. Abdomen with indistinct lateral wrinkles on ventrites 1–3; suture between ventrites 2 and 3 complete; apical male ventrite with 2 marginal setae, apical female ventrite with 4 equally spaced marginal setae and median trapezoid of 4 subequal, short setae. Legs-metatarsomere 1/metatibial length ratio 0.20; metatarsomere 4 length along outer lobe 1.2× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci broad, shallow. Microsculpture of vertex a granulate isodiametric mesh; pronotal disc with shallow transverse mesh median base with isodiametric sculpticells and glossy portions; elytral disc and apex with very shallow isodiametric sculpticells in transverse rows; metasternum with distinct transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous with piceous cast; antennomere 1 rufoflavous, antennomeres 2–11 rufopiceous; pronotal disc rufobrunneous, pronotal margins broadly paler, rufoflavous; proepipleuron flavous, proepisternum rufous; elytral disc rufobrunneous, sutural interval concolorous basally, rufous apically; elytral marginal depression narrowly rufoflavous, apex concolorous with disc; elytral epipleuron rufoflavous, metepisternum rufous; abdomen rufobrunneous mediobasally, all ventrites flavous laterally, the apical ventrite with apex broadly flavous; metafemur flavous with piceous basal cloud; metatibia rufobrunneous, piceous cast medially.

Male genitalia (n = 1). Aedeagal median lobe slender, distance from parameral articulation to tip 5.1× depth at midlength (Fig. 45H); apex extended 4× its depth beyond ostial opening, gradually narrowed to narrowly rounded tip; median lobe constricted laterally toward apex in ventral view, right margin distinctly concave, left margin more gradually narrowed, tip blunt (Fig. 45J); internal sac with bulbous ventral lobe near midlength, apex broadly rounded with small sclerotized flagellar plate visible along dorsal surface of apical lobe (Fig. 45H–I), sac surface uniformly covered with microspicules.

Female reproductive tract (n = 1). Bursa copulatrix very short, broad, little extended from broad vaginal base, length 0.23 m, breadth 0.40 mm (Fig. 46C); bursal walls translucent, thinly wrinkled; gonocoxite 1 with 3–4 apical fringe setae in oblique series, 4–6 smaller setae on medial surface (Fig. 47C); gonocoxite 2 subtriangular, apex evenly narrowed, base broadly extended laterally, 2 narrow lateral ensiform setae and broad dorsal ensiform seta with rounded apex, apical nematiform setae on medioventral surface at 0.75× gonocoxite length.

Holotype

Male (CUIC) dissected and labeled: HI: Maui Haleakala N.P. / Kuiki, below at 2134 m / N20°42.23', W156°08.00', / 16-V-2001 lot 02 sift / litter under ohia lehua / J.K. Liebherr // HOLOTYPE / Mecyclothorax / arthuri / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes

HI: Maui: Haleakala N.P., Haleakala Crater, Paliku, 2134 m el., 23-vi-1975, Burkhart (BPBM, 1), Kipahulu Vy., sift litter by day, 2100 m el., 07-v-1991 lot 05, Jessel/Medeiros (CUIC, 3), Kuiki, below, sift Metrosideros litter, 2145 m el., 16-v-2001 lot 02, Liebherr (CUIC, 2).

Etymology

Patronyms used in this revision honor the contributions of colleagues to the work in hand. The immense contributions of Dr. Arthur Medeiros in teaching the author how to conduct operative science in the Hawaiian rainforest made this entire work possible. Thus this is the first of two patronyms to honor him.

Distribution and habitat

The known distribution of M. arthuri straddles the head of Kīpahulu Valley, including Paliku in the eastern end of Haleakalā Crater, Kuiki high along the southwest valley rim, and the upper Kīpahulu Camp sampled by Medeiros and Jessel, 2100 m elevation (Fig. 51). Specimens have been collected by sifting leaf litter.

Mecyclothorax medeirosi sp. n.

Figs 49C–D, 51

Diagnosis

Like M. arthuri in exhibiting tortuously anastomosed elytral striae, though in this species all striae from the sutural to 7th stria are involved (Fig. 49C). This species also differs in the relatively broader pronotum; MEW/MPW = 1.47 versus a ratio of 1.64–1.67 for the former species. The pronotum itself is broader, more transverse, MPW/PL = 1.38, versus MPW/PL = 1.21–1.26 in M. arthuri. The elytra are also broader basally in this species, with the lateral elytral margins rounded more broadly laterad the angulate humeri (Fig. 49C) than observed in individuals of M. arthuri (Fig. 49A–B); MEW/HuW = 1.98 versus values of 2.07–2.16 for the other species. Finally, elytral setation differs between the species, with M. medeirosi characterized by three dorsal elytral setae and presence of both apical and subapical setae, producing a setal formula of 2 1 3 2. Standardized body length 4.35 mm.

Description

(n = 1). Head capsule with frontal grooves sinuous, broad near clypeus and with lateral carina posteriorly; dorsal surface of neck slightly concave; eyes convex, ocular lobe protruded from gena, ocular ratio = 1.48, ocular lobe ratio = 0.75–0.79; labral anterior margin broadly, moderately emarginate, antennae filiform, antennomeres 2–3 with sparse pelage of short setae; mentum tooth with sides acute, apex rounded. Pronotum bisetose, hind angles glabrous; base moderately constricted, MPW/BPW = 1.51; hind angle right to obtuse with rounded apex, lateral margin subparallel to slightly divergent anterad angle; median base smooth medially, 5–6 punctures mesad laterobasal depressions; basal margin slightly convex medially; median longitudinal impression deep, broad, medially incised, crossed by transverse wrinkles; anterior transverse impression deeply incised, complete, slightly irregular; anterior callosity broadly convex, crossed by many fine wrinkles; front angles slightly projected, tightly rounded; apical and basal widths subequal, APW/BPW = 1.02; lateral marginal depression moderate, edge upturned to beaded; laterobasal depression broad, flat to slightly upraised by low tubercle. Proepisternum with 5 minute punctures along hind marginal groove; prosternal process medially depressed, with narrow marginal bead. Elytra broadly subquadrate, disc moderately convex along entire length; basal groove distinctly recurved to subangulate humeral angle; parascutellar seta present; parascutellar striole narrow, deep, isolated from sutural stria; sutural and 2nd striae of subequal depth from base to apex; adjacent striae from the sutural stria to stria 7 confusedly fused, producing numerous, approximately symmetrical wartlike protuberances, all intervals convex, the warts incorporating portions of more than one interval; discal striae smooth, lined with sculpticells only; 7th and 8th interval of similar convexity mesad subapical sinuation; 3 dorsal elytral setae at 0.29×, 0.51×, and 0.64× elytral length, setal impressions very small, shallow, but associated with depressed discal strial fusions; apical and subapical setae present; lateral elytral setae arranged as anterior series of 7 setae and a posterior series of 5–6 setae, with an isolated intermediate seta present on left side; elytral marginal depression broad along anterior setal series, moderate at midlength, narrower behind; subapical sinuation shallow, broad. Mesepisternum with ~9 shallow punctures in 1–2 rows; metepisternum nearly quadrate, width to length ratio = 0.93; metepisternum/metepimeron suture distinct. Abdomen with indistinct lateral wrinkles on ventrites 1–3; suture between ventrites 2 and 3 complete; apical female ventrite with 4 equally spaced marginal setae, a median trapezoid of 4 setae, the basal setae shorter, a 5th seta on right side. Legs-metatarsomere 1/metatibial length ratio = 0.15; metatarsomere 4 length along outer lobe 1.67× median base, the tarsomere broad, robust, apical and subapical setae present; metatarsal dorsolateral sulci broad, shallow. Microsculpture of vertex a granulate isodiametric mesh; pronotal disc with granulate isodiametric mesh, some sculpticells in transverse rows; pronotal median base with granulate isodiametric mesh; elytral disc and apex with very shallow isodiametric sculpticells in shallow rows; metasternum with upraised transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous with piceous cast; antennomere 1 flavous, antennomeres 2–11 piceous; pronotal disc rufobrunneous, margins broadly paler, rufoflavous; proepipleuron flavous, proepisternum piceous (Fig. 49D); elytral disc with rufobrunneous intervals and darker brunneous depressions and striae, sutural interval concolorous with lateral intervals; elytral margins rufoflavous, apex broadly flavous; elytral epipleuron flavous, metepisternum piceous; abdomen broadly brunneous, a piceous cast mediobasally, abdominal apical ventrite broadly flavous (Fig. 49D); metafemur flavous with indistinct median rufous cloud; metatibia rufobrunneous.

Female reproductive tract. The lone female holotype was not dissected.

Holotype

Female (CUIC) labeled: HI: Maui Haleakala N.P. / Northeast Rift New / Greensword Bog sift ex / larger ohias / 17-V-1993 / lot 04 el. 1850 m // J.K. Liebherr & / A.C. Medeiros / Collectors // HOLOTYPE / Mecyclothorax / medeirosi / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Etymology

This is the second patronym to honor the contributions of Dr. Art Medeiros, most specifically for field collecting efforts validated in this revision, and more broadly for his leadership in Hawaiian conservation biology (e.g., Perkins et al. 2014). Both M. arthuri and M. medeirosi occupy distributional ranges in Kīpahulu Valley and the Hāna Bogs region of Haleakalā (Fig. 51). Based on the species known to science to date, the species’ hypothesized sister-taxon relationship can be signified by the convention, M. arthuri + M. medeirosi.

Distribution and habitat

The single specimen used as the basis for this species description was collected by sifting humus and leaf litter from under an ‘ōhi‘a tree adjacent to New Greensword Bog (Fig. 51).

Mecyclothorax inconscriptus sp. n.

Figs 45K–L, 46D, 47D, 50A, 51

Diagnosis

This is one of the three species in the group with body lengths of 4.1 mm or less, accompanying M. bradycelloides and M. anthracinus in that distinction, however M. inconscriptus (Fig. 50A) incongruently differs from those species by sharing with M. foveolatus and M. interruptus below (Fig. 50B–D), the state of elytral striae 2–4 fused in association with the dorsal elytral setae. The pronotum is basally constricted, MPW/BPW = 1.49–1.52, versus values of 1.38–1.47 for M. foveolatus and M. interruptus. Pronotal setation also differs from all four species mentioned above in that the basal setae are absent from a slight majority of available specimens, and in the minority of specimens that exhibit the basal setae, they are small and underdeveloped; therefore setal formula 2 1(2) 2 2. Standardized body length 3.7–4.0 mm.

Figure 50.

Mecyclothorax interruptus group species, dorsal habitus view. A M. inconscriptus (Kaupō Gap, 1495 m) B M. foveolatus (Kuhiwa E rim, 880 m) C M. interruptus lectotype on Fauna Hawaiiensis mounting card; “Mecyclothorax interruptus Type D. S.” D M. interruptus (Honomanu, 1680 m).

Description

(n = 5). Head capsule with frontal grooves deep near clypeus, straight with lateral carina; dorsal surface of neck convex; ocular lobe obtusely projected from genal surface, eyes little convex, ocular ratio = 1.36–1.44, ocular lobe ratio = 0.72–0.77; labral anterior margin broadly, shallowly emarginate; antennae filiform, antennomere 3 with sparse pelage of short setae; mentum tooth with sides acute, apex tightly rounded. Pronotum transverse, MPW/PL = 1.31–1.37; hind angle obtuse rounded to denticulate, lateral margin straight for short distance to immediately sinuate anterad angle; median base with dense elongate punctures and wrinkles; basal margin nearly straight, slightly convex medially; median longitudinal impression shallow, finely incised, crossed by fine wrinkles; anterior transverse impression shallow, broad, crossed by fine wrinkles; anterior callosity slightly convex, crossed by fine wrinkles; front angles slightly projected, tightly rounded; apical width subequal to slightly larger than basal width, APW/BPW = 1.0–1.04; lateral marginal depression moderate, edge upturned to beaded; laterobasal depression broad, surface wrinkled. Proepisternum with 6 minute punctures along hind marginal groove; prosternal process medially depressed with broad marginal bead. Elytra subquadrate, disc flat, sides moderately sloped; basal groove slightly recurved to rounded humeral angle, the humeri moderately narrowed relative to greatest width behind midlength, MEW/HuW = 1.93–2.05; parascutellar seta present; parascutellar striole fine, continuous, with 6 small punctures; sutural interval moderately convex, slightly more elevated than intervals 2–4; sutural and 2nd striae of subequal depth from base to apex; discal striae deep, impunctate, continuous to apex with exception of strial fusions; strial fusions include those of striae 3 and 4 in association with dorsal elytral setae, striae 5 and 6 posterad humerus, and irregularly striae 3 and 4, 4 and 5, and 5 and 6 near apex (Fig. 50A); 7th and 8th interval of similar convexity mesad subapical sinuation; 2 dorsal elytral setae at 0.29× and 0.61–0.65× elytral length, setal impressions foveate, spanning interval 3; apical and subapical setae present; lateral elytral setae arranged in anterior series of 7 setae and posterior series of 5 setae; elytral marginal depression narrow, lateral margin upturned; subapical sinuation very shallow, nearly obsolete. Mesepisternum with 8 shallow punctures in 2 rows; metepisternal width to length ratio = 0.86; metepisternum/metepimeron suture distinct; metathoracic flight wing an ovoid flap 2.5× long as wide, remnant R plus M veins present, vestige extends ¾ distance to posterior margin of metanotum. Abdomen with indistinct lateral wrinkles on ventrites 1–3; suture between ventrites 2 and 3 complete; apical male ventrite with 2 marginal setae, apical female ventrite with 4 equally spaced marginal setae and median trapezoid of 4 subequal, short setae. Legs-metatarsomere 1/metatibial length ratio = 0.17; metatarsomere 4 length along outer lobe 1.3× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci broad, shallow. Microsculpture of vertex granulate isodiametric; pronotal disc with granulate transverse mesh, median base with granulate isodiametric mesh; elytral disc with elongate transverse mesh, apex with well-developed isodiametric mesh in transverse rows; metasternum with upraised transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous; antennomere 1 flavous, antennomeres 2–3 rufopiceous, 4–11 piceous; pronotal disc rufobrunneous with piceous cast, margins concolorous; proepipleuron rufoflavous, proepisternum rufobrunneous with piceous cast; elytral disc rufopiceous, sutural interval paler, rufous throughout length, lateral marginal depression paler at base, 8th stria and depression paler at apex; elytral epipleuron rufoflavous, metepisternum rufobrunneous; abdomen rufopiceous across width of ventrites 1–5, apical ventrite 6 with apical 1.3 paler, rufobrunneous; metafemur flavous with piceous cast in basal 1/3; metatibia flavous with piceous cast.

Male genitalia (n = 1). Aedeagal median lobe short, robust, distance from parameral articulation to tip 2.2× depth at midlength (Fig. 45K); apex narrowly extended beyond ostial opening 3× its depth, tip tightly rounded at juncture of flattened apical face and downturned ventral margin; median lobe straight in ventral view, right and left margins convergent to blunt tip (Fig. 45L); internal sac unornamented, flagellar plate large, sclerotized plate visible in lateral view, plate length 0.58× parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix very broad basally, narrowed to a nipplelike apical lobe, overall length 0.51 mm, apical lobe width 0.09 mm, basal width at vagina 0.44 mm (Fig. 46D); bursal walls transparent at base, wrinkled in extension apicad juncture with common oviduct, apical lobe translucent, thinly wrinkled; gonocoxite 1 with 2 subequal apical fringe setae, 4 smaller setae on medial surface (Fig. 47D); gonocoxite 2 broadly subtriangular, apex tightly rounded, base broadly extended, 2 lateral ensiform setae with apical seta broader and longer, apical nematiform setae on medioventral surface at 0.72× gonocoxite length.

Holotype

Male (CUIC) dissected and labeled: HI: Maui Haleakala N.P. / Kaupo Gap el. 1495 m / N20°41'48", W156°08'22" / 17-18-V-2001 lot03 koa/ / fern/moss litter J. Liebherr / 2 / HOLOTYPE / Mecyclothorax / inconscriptus / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes

HI: Maui: Haleakala N.P., Haleakala Crater, Paliku, pitfall, 1900 m el., 14-15-iii-2002, Takumi (BPBM, 1), Kaupo Gap, sift litter Acacia koa/fern/moss, 1495 m el., 17–18-v-2001 lot 03, Liebherr (CUIC, 5).

Etymology

The Latin participle conscriptus is used as the stem of this epithet, with the converse inconscriptus signifying this species’ membership in the M. interruptus species group.

Distribution and habitat

M. inconscriptus exhibits a Kaupō Gap distribution (Fig. 51) biogeographically congruent with that of M. cordaticollaris (Fig. 77). The two collecting records indicate occupation of mesic to dry ground-level microhabitats, with one specimen collected in a pitfall trap at Paliku, and a series of four individuals found in a sift sample of Acacia koa leaves, mosses, and dead fern fronds.

Figure 51.

Recorded geographic distributions of M. interruptus group species.

Mecyclothorax foveolatus sp. n.

Figs 45M–N, 46E, 47E, 50B, 51

Diagnosis

This and the following species, M. interruptus, are cryptic sibling species with only subtle differences both externally (Fig. 50B, D) and in the male genitalia (Fig. 45M–P), but nevertheless they may be consistently diagnosed morphologically. This species differs from its sibling in its more upraised cuticular microsculpture; 1, vertex covered by a granulate isodiametric mesh, the surface appearing coriaceous, matte and non-reflective; 2, pronotal disc with coriaceous isodiametric and transverse sculpticells in transverse rows, the pronotal base with granulate isodiametric mesh, again the surface with a matte finish. The corresponding microsculpture in M. interruptus individuals is: 1, vertex with isodiametric mesh, the sculpticell surfaces shiny in part; 2, pronotal disc with mixture of isodiametric and transverse sculpticells, the surface iridescent, and pronotal base with flattened isodiametric sculpticells, the surface shiny in part. The discal elytral striae are also smoother in this species, with minute punctulae at the deepest parts of the striae associated with longitudinal irregularities in the strial orientation, whereas in M. interruptus individuals the striae, especially the sutural and 2nd stria, are minutely but clearly punctate in their deepest portions, with those small punctures slightly expanding the stria at its deepest point. The male median aedeagal lobe apex in this species has a distinct obtuse tooth on its dorsal surface (Fig. 45M–N) versus the lobe apex of M. interruptus males with a rounded dorsal projection (Fig. 45O–P). The median lobe tip is also flattened apically in this species, versus more evenly rounded in M. interruptus. Setal formula 2 2 2 2. Standardized body length 4.8–5.9 mm.

Description

(n = 5). Head capsule with frontal grooves deep and broad near clypeus, sinuously directed to terminus mesad anterior supraorbital seta; dorsal surface of neck flat to convex; eyes moderately convex, ocular ratio = 1.42–1.50, ocular lobe distinctly projected from gena; ocular lobe ratio 0.79–0.88; labral anterior margin with broad, moderately deep emargination; antennae filiform, antennomere 3 with sparse pelage of short setae; mentum tooth with side acute, apex broadly rounded. Pronotum moderately transverse, MPW/PL = 1.19–1.29, moderately constricted basally, MPW/BPW = 1.38–1.46; hind angle variably obtuse, to right, to slightly acute, apex tightly rounded, lateral margin subparallel anterad angle; median base with dense elongate punctures and longitudinal wrinkles; basal margin nearly straight, slightly convex medially; median longitudinal impression broad, shallow, crossed by wrinkles; anterior transverse impression deeply incised, complete, crossed by longitudinal wrinkles that extend across broadly, slightly convex anterior callosity; front angles slightly projected, rounded; pronotal apical and basal widths subequal, APW/BPW = 0.95–1.06; lateral marginal depression moderate, edge broadly upturned; laterobasal depression broad, smooth, with median tubercle. Proepisternum with 6 small, elongate punctures along hind marginal groove; prosternal process broad, medially depressed with lateral marginal bead. Elytra subquadrate, disc slightly convex; basal groove evenly recurved to join lateral marginal depression at rounded humerus; MEW/HuW = 1.79–2.02; parascutellar seta present (on 1 specimen near base of stria 2); parascutellar striole deep, continuous; sutural interval moderately convex, convexity similar to that of lateral intervals of similar breadth; sutural and 2nd striae of subequal depth from base to apex; discal striae 2–4 fused in association with dorsal elytral setae, striae 5 and 6 may be fused behind humerus, intervals moderately convex to convex; 7th and 8th intervals of similar convexity mesad subapical sinuation; 2 dorsal elytral setae at 0.29× and 0.60× elytral length, setal impressions foveate, placed within depressed areas associated with strial fusions; apical and subapical setae present; lateral elytral setae arranged as anterior series of 7 setae (or anterior series of 6 with isolated 7th intermediate seta) and a posterior series of 6 setae; elytral marginal depression narrow, lateral margin upturned; subapical sinuation broad and very shallow. Mesepisternum with ~22 distinct punctures 3–4 rows; metepisternal width to length ratio = 0.76; metepisternum/metepimeron suture distinct; metathoracic flight wing configuration an ovoid flap, length 2.1× breadth, remnant R and M veins present, the flap extended 1/3 length beyond posterior margin of metanotum. Abdomen with indistinct lateral wrinkles on ventrites 1–3; suture between ventrites 2 and 3 complete; apical male ventrite with 2 marginal setae, apical female ventrite with 4 equally spaced marginal setae and median trapezoid of 4 short setae, the basal pair slightly longer. Legs-metatarsomere 1/metatibial length ratio = 0.22; metatarsomere 4 length along outer lobe 1.4× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci broad, deep, median area irregular. Microsculpture of elytral disc an elongate transverse mesh, apex with upraised transverse mesh; metasternum with obsolete transverse mesh; laterobasal abdominal ventrites with elongate transverse mesh and glossy areas. Coloration of vertex brunneous; antennomere 1 flavous, antennomeres 2–3 flavous with a piceous cast, 4–11piceous; pronotal disc brunneous with piceous cast, margins broadly rufoflavous; proepipleuron flavous with rufous cast, proepisternum rufopiceous; elytral disc rufobrunneous with piceous cast, sutural interval concolorous, margins concolorous to slightly darker; elytral epipleuron flavous with rufous cast, metepisternum piceous; abdominal ventrites 1–6 piceous medially, flavous laterally, the apical ventrite flavous in apical half; metafemur flavous; metatibia flavous with brunneous cast.

Male genitalia (n = 2). Aedeagal median lobe slender, distance from parameral articulation to tip 6.6× depth at midlength (Fig. 45M), shaft slightly curved basally, ventral margin straight apically, apex with acute dorsal projection, tip tightly rounded at juncture of flat apical face and ventral margin; in ventral view median lobe slightly curved rightward toward apex, right margin concave, left margin more incurved to apex, apical denticle visible to left of rounded tip (Fig. 45N); internal sac without ornamentation.

Female reproductive tract (n = 1). Bursa copulatrix elongate with broad base at vagina, length 0.60 mm, apical width 0.23 mm, basal width 0.34 mm (Fig. 46E); bursal walls translucent, thinly wrinkled; gonocoxite 1 with 4 apical fringe setae and 4–6 smaller setae on medial surface (Fig. 47E); gonocoxite 2 subtriangular, apex acuminate, base evenly extended from lateral margin, 2 parallel-sided lateral ensiform setae, apical nematiform setae on medioventral surface at 0.79× gonocoxite length.

Holotype

Male (CUIC) dissected and labeled: HI: Maui Haleakala N.P. / Kipahulu west rim ESE / Kuiki, sift humus ex ohia / 15-V-1993 lot 03 / el. 1850 m // J.K. Liebherr / A.C. Medeiros, / Jr. collectors // HOLOTYPE / Mecyclothorax / foveolatus / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes

HI: Maui: Haleakala N.P., Kipahulu Vy., Central Pali Tr., sift leaf/moss litter, 1200 m el., 29-iv-1991 lot 03, Liebherr/Medeiros (CUIC, 1), Kipahulu west rim ESE Kuiki, sift Metrosideros humus, 1850 m el., 15-v-1993 lot 05, Liebherr/Medeiros (CUIC, 1); Hana For. Res., Kaumakani Peak, pyrethrin fog vegetation, 1165 m el., 08-vi-1999 lot 04, Polhemus (NMNH, 1); Koolau For. Res., Hanawi N.A.R., Kopiliula Str., pyrethrin fog Acacia koa trunk, 1127 m el., 03-v-1998 lot 02, Liebherr (CUIC, 1), Kuhiwa Vy. E rim, pyrethrin fog Metrosideros, 880 m el., 09-vi-1999 lot 04, Polhemus (NMNH, 1), lot 07, Polhemus (NMNH, 2), lot 09, Polhemus (NMNH, 1).

Etymology

The foveae surrounding dorsal elytral setae of this species are the basis for use of the Latin adjectival foveatus as this species’ epithet.

Distribution and habitat

M. foveolatus exhibits a highly fragmented distribution comprising five localities spanning the Manawainui Planeze, Kīpahulu Valley, Kaumakani Peak, and Kuhiwa and Kopili‘ula drainages in Hanawī (Fig. 51). The Kopili‘ula record alone is associated with koa, whereas the other records are associated with ‘ōhi‘a; either through sifting leaf litter, humus, or moss, or by using pyrethrin fog on mossy trunks and logs.

Mecyclothorax interruptus Sharp

Figs 45O–P, 46F, 47F, 50C–D, 51

Mecyclothorax interruptus Sharp 1903: 252; Britton 1948b: 163.

Mecyclothorax interruptus var. dubius Sharp 1903: 252; Britton 1948b: 163 (synonymy).

Diagnosis

This species (Fig. 50D) can be diagnosed from its cryptic sibling species, M. foveolatus (Fig. 50B), using the criteria presented under that species (above). These two are the only Haleakalā species exhibiting: 1, strial fusion implicating striae 2–4 at the positions of the dorsal elytral setae; and 2, body sizes above 5 mm. Setal formula 2 2 2 2. Standardized body length 5.0–5.4 mm.

Identification

(n = 5). The eyes are moderately convex, ocular ratio = 1.37–1.50, and they cover much of the ocular lobe (Fig. 50D), ocular lobe ratio = 0.79–0.88. The pronotum is little constricted basally, MPW/BPW = 1.35–1.43, with the hind angle right to slightly obtuse, and the lateral margin briefly sinuate before the angle. The pronotal disc is smooth, glossy, with fine transverse wrinkles that extend little from the shallow, finely incised median longitudinal impression. The pronotal median base is covered with small punctures and fine longitudinal wrinkles. The elytra are subquadrate, with the humeri broadly rounded; MEW/HuW = 1.68–1.94. The dorsal body coloration is dark, with the vertex and pronotal disc rufopiceous, elytral disc rufobrunneous, and metafemur and metatibia flavous with a brunneous cast.

Male genitalia (n = 3). Aedeagal median lobe very slender, distance from parameral articulation to tip 6.8× depth at midlength (Fig. 45O), shaft slightly curved basally, ventral margin dorsally recurved apically, apex with bluntly rounded dorsal projection, tip broadly tightly rounded, apical face convex; in ventral view median lobe slightly curved rightward toward apex, right margin slightly concave, left margin more incurved to rounded apex, blunt projection visible as apical expansion of rounded tip (Fig. 45P); internal sac without ornamentation.

Female reproductive tract (n = 1). Bursa copulatrix a narrow tube with apical lobe, medial bulge, and basal constriction (Fig. 46F), overall length 0.80 mm, apical breadth 0.17 mm, medial bulge breadth 0.23 mm; bursal walls translucent, thinly wrinkled; gonocoxite 1 with 2–3 apical fringe setae and 5–6 smaller setae on medial surface (Fig. 47F); gonocoxite 2 subtriangular, apex broad, base evenly extended laterally from curved lateral margin, 2 broad lateral ensiform setae, apical nematiform setae on medioventral surface at 0.73× gonocoxite length.

Lectotypes

For Mecyclothorax interruptus Sharp, female (BMNH) hereby designated, labeled: ♀ (in pencil) / Mecyclothorax / interruptus / Type D.S. / Haleakala / Perkins 597 (on obverse of mounting platen) // Type (round, red-margined label) // Hawaiian Is. / Perkins / 1904–336. / LECTOTYPE / Mecyclothorax / interruptus / Sharp / J.K. Liebherr 1998 (black-margined red label). For Mecyclothorax interruptus var. dubius Sharp, female (BMNH) hereby designated, labeled: M. in- / terruptus. var / dubius. D.S. / Haleakala / Perkins (on obverse of mounting platen), 623. (on reverse of platen) // Hawaiian Is. / Perkins / 1904–336. // LECTOTYPE / Mecyclothorax / interruptus var. dubius / Sharp / J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat

M. interruptus is broadly distributed across the Waikamoi block of forest from 1170–1860 m elevation (Fig. 51). This species has been found by sifting ‘ōhi‘a leaf litter, searching under boards or logs on the ground, and by pyrethrin sampling moss-covered standing tree trunks and horizontal nurse logs.

Mecyclothorax sobrinus species group

Diagnosis. Species placed in this group display dorsal elytral setae set in foveate impressions spanning the third interval, plus well-developed, isodiametric dorsal microsculpture—just as do species in the M. interruptus group. But this group’s species are also characterized by shallower lateral elytral striae 6 and 7, whereas in the M. interruptus group species all striae—sutural to 8th—are of subequal depth. This distinction was established in Britton’s (1948b) classification. In M. sobrinus group species, the 8th elytral interval is convexly raised mesad the subapical sinuation so that it is more convex than both the 9th interval bordering the lateral marginal depression and the apical portion of fused striae 5 + 7. In association with this convexity, stria 7 is markedly depressed apicolaterad the narrowed termination of interval 6 associated with fusion of intervals 5 and 7. These characters represent synapomorphies for this group. Mecyclothorax sobrinus group species exhibit both anterior and posterior supraorbital setae, lateral and basal pronotal setae, apical and subapical elytral setae, and at least 2 dorsal elytral setae, leading to a base setal formula of 2 2 2 2. Mecyclothorax multipunctatus and M. inaequalis deviate from this formula by including individuals that exhibit additional setae on the 5th, or 5th and 7th elytral intervals. For these species, the impressions that connect the outward adjacent striae are associated with setae; a condition not observed in M. interruptus group species. As all species in both groups are predominantly encountered at the soil level within leaf litter and humus, the possibility that foveate setal impressions and strial fusions converge on some sort of cryptic litter-running facies that can confuse visual predators—presumably avian first, but presently also including the entomologist—should not be discarded out of hand. Conversely, dimpled elytra may serve better to reduce drag during a beetle’s wedge-pushing (Evans 1977) through the leaf and humus layers, at the same time positioning dorsal sensory setae within protective fossae.

Membership and distribution. This monophyletic species group comprises seven species restricted to Haleakalā. As West Maui, Moloka‘i, and Haleakalā lost terrestrial connections on the order of 700,000 years ago (Price and Elliott-Fisk 2004), several competing hypotheses present themselves regarding this distributional pattern: 1, the group has radiated on Haleakalā within the past 700,000 years; 2, some biogeographic barrier or ecological criterion restricted this group to Haleakalā during earlier times when the present-day fragments of Maui Nui were terrestrially connected; 3, representatives of this group remain undiscovered, or underwent extinction in West Maui or Moloka‘i. Data currently in hand support a narrow set of ecological preferences for these species, as five of them are sympatrically distributed in Koa-‘Ōhi‘a Mesic Forest within the Waikamoi area, whereas the remaining two are restricted to the mesic forest at Polipoli (Figs 56, 59).

Key to adults of the Mecyclothorax sobrinus species group, Haleakalā volcano, Maui, Hawai‘i

1 Dorsal elytral setae in intervals 3 and 5, or 3, 5, and 7 (Fig. 52A–B) 2
1’ Two dorsal elytral setae restricted to third interval (Figs 52C–D, 57) 3
2(1) Dorsal elytral setae in striae 3 and 5, unilaterally in interval 7 in some specimens, the elytral striae regular, not fused in association with the setae (Fig. 52A); elytral intervals with regular transverse-mesh microsculpture (036) M. multipunctatus (Blackburn)
2’ Dorsal elytral setae situated in intervals 3, 5, and 7, adjacent elytral striae fused in association with setae (Fig. 52B); elytral intervals with coriaceous isodiametric microsculpture, the surface pearlaceous (037) M. inaequalis (Blackburn)
3(1) Elytra subquadrate to subellipsoid, lateral margins convex, greatest width may be behind midlength (Figs 52D, 57) 4
3’ Elytra quadrate, broad basally with subparallel lateral margins (Fig. 52C) (038) M. longulus Sharp
4(3) Larger beetles, standardized body length 5.5–6.6 mm; vertex and pronotal disc with upraised isodiametric to transverse microsculpture, the surface pearlaceous (Fig. 57) 5
4’. Smaller beetles, standardized body length 4.5–4.9 mm; vertex and pronotal disc with transverse mesh microsculpture, the surface glossy (Fig. 52D) (039) M. giffardi Liebherr
5(4) Elytral humeri broad, lateral margins evenly convex with maximum width at position between anterior and posterior dorsal elytral setae (Fig. 57B–C); male aedeagal median lobe with a spatulate apex and a projected parapical extension (Fig. 58) 6
5’ Elytral humeri narrow, maximum elytral width at position of posterior dorsal elytral setae (Fig. 57A); male aedeagal median lobe a simple shaft without parapical extension (Fig. 53H) (040) M. foveopunctatus sp. n.
6(5) Dorsal surface with exceedingly upraised microsculpture, the isodiametric sculpticells of vertex, pronotal disc, and elytral disc causing intense pearlaceous reflection (Fig. 57B); 2–4 dorsal elytral setae each side in third interval, their positions often unilaterally asymmetrical; elytral intervals 3–6 distinctly and irregularly depressed posterad humerus; male aedeagal median lobe with broad, spatulate apex and robust parapical extension (Fig. 58A–B) (041) M. consobrinus Liebherr
6’ Dorsal surface with regular upraised isodiametric microsculpture, the sculpticells in transverse rows on pronotal and elytral discs, surface evenly pearlaceous (Fig. 57C); 2 dorsal elytral setae each side, nearly always symmetrically paired; elytral intervals 4–6 moderately and evenly depressed posterad humerus; male aedeagal median lobe with narrow, hooked apex and digitiform parapical extension (Fig. 58D–E) (042) M. sobrinus Sharp

Mecyclothorax multipunctatus (Blackburn)

Figs 52A, 53A–C, 54A, 55A, 56

Cyclothorax multipunctatus Blackburn 1878a: 122; Blackburn and Sharp 1885: 214.

Mecyclothorax multipunctatus, Sharp 1903: 252; Britton 1948b: 156.

Diagnosis

This species is uniquely diagnosed by the presence of 1–3 setae in interval 5 accompanying the usual two dorsal elytral setae in interval 2, and broad subquadrate elytra with intervals of consistent breadth that bear regular, transverse-mesh microsculpture. When only one supplementary 5th interval seta is present, it is situated behind the position of the posterior dorsal elytral seta of the 3rd interval (Fig. 52A). When two extra 5th interval setae are present, they include the posterior trailing seta, plus a 2nd seta situated between the positions of the anterior and posterior dorsal elytral setae. A third 5th interval seta may be present, situated at a position immediately posterad or anterad the anterior dorsal elytral seta of interval 3. Setal formula 2 2 2 2. Standardized body length 4.5–5.5 mm.

Figure 52.

Mecyclothorax sobrinus group species, dorsal habitus view. A M. multipunctatus (nr. Ukulele Camp, 1615 m) B M. inaequalis (nr. Ukulele Camp, 1615 m) C M. longulus (nr. Ukulele Camp, 1615 m) D M. giffardi (Kahikinui, 1616 m).

Identification

(n = 5). The pronotum is transverse, MPW/PL = 1.32–1.42, with base broad, MPW/BPW = 1.41–1.44, and hind angles obtuse, with the lateral margins only slightly and briefly sinuate before the angles. The pronotal median base is slightly depressed relative to the disc, and covered with distinct longitudinal punctures and wrinkles. The elytra are broad basally, with the basal groove distinctly recurved to meet the lateral marginal depression at the subangulate humerus; MEW/HuW = 1.83–1.98. The sutural stria is deep with minute punctures to slight irregularities basally, deep and smooth apically. The mesepisternum bears ~8 punctures in 1–2 rows. The cuticular microsculpture is similar to all other species in the group, but the following combination is unique among those species: 1, vertex with upraised isodiametric sculpticells in transverse rows; 2, pronotal disc with transverse mesh, sculpticell breadth 2× length; 3, pronotal median base with granulate isodiametric mesh; 4, elytral disc covered with transverse mesh, sculpticell breadth 2× length; 5, elytral apex with transverse mesh, sculpticell breadth 3× length, to transverse lines.

Male genitalia (n = 4). Aedeagal median lobe moderately robust, distance from parameral articulation to tip 3.8× depth at midlength (Fig. 53A); apical extension beyond ostial opening with broadly convex dorsal projection, the tip slightly downturned and rounded; median lobe broad basally, thinly curved rightward apically in ventral view (Fig. 53C), the apex expanded slightly at tip; internal sac with ventral lobe at midlength (Fig. 53B; similar to ventral lobe of M. arthuri, Fig. 45H–I), the apical lobe bearing the flagellar plate smaller than the ventral lobe; flagellar plate short, the sclerotized ventral face 0.27× as long as parameral articulation-tip distance; sac with broad, diffuse ventral ostial microtrichial patch, otherwise covered with fine microspicules.

Figure 53.

Male aedeagus, M. sobrinus group species (for abbreviations see Table 2, p. 23). A–C M. multipunctatus (nr. Ukulele Camp, 1615 m). A Right view B Right view, sac everted C Ventral view D M. inaequalis, right view (nr. Ukulele Camp, 1615 m) E–F M. longulus, right and ventral views (nr. Ukulele Camp, 1615 m) G M. giffardi, right view, sac everted (Kahikinui, 1616 m) H M. foveopunctatus, right view (Ukulele Camp Pipeline, 1495–1525).

Female reproductive tract (n = 1). Bursa copulatrix columnar, broad with rounded apex, length 0.82 mm, breadth 0.43 mm, a heavily sclerotized plate dorsad the bursa copulatrix-common oviduct juncture, this hemi-elliptical bursal sclerite with both basal breadth and medial tarsomere length = 0.30 mm (Fig. 54A); bursal walls translucent with thick wrinkles; gonocoxite 1 with 3–4 apical fringe setae, a curved seta just basad medioapical angle and 3–5 smaller setae on medial surface (Fig. 55A); gonocoxite 2 subfalcate with a tightly rounded apex, broadly extended laterally at base, 2 lateral ensiform setae with apical seta broader and longer, apical nematiform setae on medioventral surface at 0.70× gonocoxite length.

Figure 54.

Female bursa copulatrix and associated reproductive structures, M. sobrinus group species, ventral view (for abbreviations see Table 2, p. 23). A M. multipunctatus (nr. Ukulele Camp, 1615 m) B M. inaequalis (nr. Ukulele Camp, 1615 m) C M. longulus (nr. Ukulele Camp, 1534–1660 m) D M. consobrinus (Polipoli, 1890 m). E M. sobrinus (Honomanu, 1830–1860 m). Scale bar = 0.50 mm.

Figure 55.

Left female gonocoxa, M. sobrinus group species, ventral view. A M. multipunctatus (nr. Ukulele Camp, 1615 m) B M. inaequalis (nr. Ukulele Camp, 1615 m) C M. longulus (nr. Ukulele Camp, 1534–1660 m) D M. consobrinus (Polipoli, 1890 m). E M. sobrinus (Honomanu, 1830–1860 m).

Lectotype

Female (BMNH) hereby designated, labeled: Mounting platen with Blackburn Maui code (Zimmerman 1957: 210), Cyc multipunc (on reverse) // Type // Hawaiian Is. Rev. T. Blackburn 1888-30. // LECTOTYPE Cyclothorax multipunctatus Blackburn J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat

M. multipunctatus is distributed in the forests of the Waikamoi and Honomanu drainages from 1210–1615 m elevation (Fig. 56). Most specimens have been collected in more mesic Koa-‘Ōhi‘a Forest, most often on the ground; under logs or in sifted leaf litter. It has also been found on koa trunks, or associated with Cibotium (hāpu‘u) tree ferns. On 7-v-1998, specimens of this species were collected from under large ohia logs in the mesic forest at Ukulele Pipeline along with M. foveopunctatus and M. sobrinus of this species group, plus the less closely related species M. cognatus, M. consanguineus, M. cymindicus, and M. filipoides.

Figure 56.

Recorded geographic distributions of M. sobrinus group species.

Mecyclothorax inaequalis (Blackburn)

Figs 52B, 53D, 54B, 55B, 56

Cyclothorax inaequalis Blackburn 1878b: 157; Blackburn and Sharp 1885: 216.

Mecyclothorax inaequalis, Sharp 1903: 249; Britton 1948b: 142.

Diagnosis

Individuals of this species are instantly recognizable by the lustrous, shimmery dorsal surface resulting from the well-developed isodiametric and transverse microsculpture, and the presence of elytral setae on intervals 3, 5, and 7 (Fig. 52B). The dorsal surface appears similar in reflective pattern to that of the fire-adapted Sericoda species (Liebherr 1991). In M. inaequalis, there are 4–6 setae on elytral interval 3, 3–5 setae on interval 5, and 3 on interval 7, each seta associated with partial convergence of the adjacent elytral striae. The dorsal microsculpture is arrayed as: 1, vertex with upraised isodiametric mesh, the sculpticells in transverse rows on the neck; 2, pronotal disc with upraised, slightly transversely stretched sculpticells in transverse rows, the median base with granulate isodiametric sculpticells, some in rows; 3, elytral disc with irregular, upraised isodiametric sculpticells plus a transverse mesh, sculpticell breadth 2× length, the apex with a shiny transverse mesh, sculpticell breadth 2–3× length. Setal formula 2 2 4 2. Standardized body length 3.9–4.7 mm.

Identification

(n = 5). The eyes are moderately convex, ocular ratio = 1.39–1.45, and situated on protruded ocular lobes, ocular lobe ratio = 0.73–0.79. The pronotum is moderately constricted basally, MPW/BPW = 1.45–1.52, and transverse, MPW/PL = 1.34–1.40. The pronotal hind angles are nearly right with an obtuse-rounded apex, and the lateral margins are subparallel for a short distance anterad the angles. The elytra are subquadrate, with rounded humeri extended laterally on the broadly rounded elytral base; MEW/HuW = 1.91–1.96. The variable dorsal reflective pattern belies monotonous dorsal coloration, with the vertex and pronotal disc brunneous with a slight piceous cast, the elytra rufobrunneous to brunneous, the apex slightly darker due to a piceous cast. Only the antennal base—antennomeres 1–3 and the base of 4—and legs deviate by their flavous coloration; the femora with a broad piceous cloud across their basal third, and the tibiae with an apically more developed piceous cast

Male genitalia (n = 1). Aedeagal median lobe gracile, distance from parameral articulation to tip 4.7× depth at midlength (Fig. 53D); apex broadly flat with subangulate ventral tip, blunt dorsal projection; internal sac with dark fields of spicules, flagellar plate short, 0.29× as long as parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix columnar, elongate with rounded apex, length 0.91 mm, breadth 0.34 mm (Fig. 54B); bursal walls translucent with thin wrinkles basally, wrinkles thicker apically; gonocoxite 1 with 3 apical fringe setae and 6–7 smaller setae on medial surface (Fig. 55B); gonocoxite 2 falcate with tightly rounded apex, base broadly extended laterally, 2 lateral ensiform setae with apical seta longer and broader, apical nematiform setae on medioventral surface at 0.65× gonocoxite length.

Lectotype

Male (BMNH) hereby designated, labeled: Mounting platen with Blackburn Maui code (Zimmerman 1957: 210), inaequalis (on reverse) // Type // Hawaiian Is. Rev. T. Blackburn 1888-30. // LECTOTYPE Cyclothorax inaequalis Blackburn J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat

M. inaequalis is a species recorded only from ground-level microhabitats in the mesic forests west of Waikamoi Gulch (Fig. 56), with collecting localities ranging 1210–1615 m elevation. Anonymous (N D) lists the species in Perkins’ lot 251: “all the small Carabids and Hem[e]iptera by grubbing.” In a modern exercise of the grubbing method on 14-v-1998 at Ukulele Pipeline, this species was collected along with individuals of M. cognatus, M. longulus, and M. sobrinus. In a subsequent grubbing attempt—16-v-2003 along the Sugi Ridge Trail, Waikamoi Nature Conservancy Preserve—the species list added M. multipunctatus and M. perstriatus to the above.

Mecyclothorax longulus Sharp

Figs 52C, 53E–F, 54C, 55C, 56

Mecyclothorax longulus Sharp 1903: 251; Britton 1948b: 143.

Diagnosis

It is the narrow, parallel-sided body shape (Fig. 52C) that diagnoses this species. The quadrate, elongate elytra exhibit only slightly convex lateral margins and relatively broad humeri, MEW/HuW = 1.83–1.93, and the pronotum is very broad relative to the elytra, MEW/MPW = 1.33–1.36. In this group, only M. consobrinus (Fig. 57B) and M. sobrinus (Fig. 57C) exhibit such quadrate elytra, but their body sizes are much larger; standardized body length for these two species spans 5.5–6.6 mm versus a standardized body length of 5.1–5.3 for M. longulus. Setal formula 2 2 2 2.

Figure 57.

Mecyclothorax sobrinus group species, dorsal habitus view. A M. foveopunctatus (Ukulele Camp Pipeline, 1495–1525 m) B M. consobrinus (Polipoli, 1500 m) C M. sobrinus (Honomanu, 1830–1860 m).

Identification

(n = 4). As above for the pronotum, head broad, MEW/MHW = 2.00–2.06, the eyes moderately convex, ocular ratio = 1.40–1.46. The lateral margins of the pronotum are only slightly sinuate anterad the obtuse, non-projected hind angles. The pronotal median base is indistinctly punctate, with 8–11 distinct rounded punctures or elongate longitudinal wrinkles each side, and the smooth laterobasal depression has a broad median tubercle. The discal elytral striae are minutely punctate, with associated intervals 1–5 slightly convex. The elytral setae consist of the parascutellar seta, 2 dorsal elytral setae at 0.33–0.35× and 0.60–0.62 and 0.60–0.62× elytral length, apical and subapical setae, and lateral setae arranged in an anterior series of 7 setae plus a posterior series of 6 setae. The dorsal microsculpture includes: 1, vertex with an upraised isodiametric mesh in transverse rows; 2, pronotal disc with upraised transverse mesh, sculpticell breadth 2× length, the median base with granulate isodiametric sculpticells intermixed with some transverse sculpticells; 3, elytral disc with an upraised isodiametric mesh, the apex with the isodiametric and slightly transversely stretched sculpticells in transverse rows.

Male genitalia (n = 1). Aedeagal median lobe gracile, distance from parameral articulation to tip 4.3× depth at midlength (Fig. 53E); apex extended 3× its depth beyond ostial opening, apex expanded dorsoventrally with ventral margin convex before rounded tip; median lobe distinctly curved to right in ventral view distad apex of ostial opening (Fig. 53F); internal sac covered with dark fields of microspicules, short flagellar plate visible inside dorsal margin of lobe, length 0.26× parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix columnar, short and broad, the dimensions dictated by a heavily sclerotized, hemi-elliptical plate dorsad bursa copulatrix-median oviduct juncture, bursal length 0.48 mm, breadth 0.40 mm, the same dimensions as bursal sclerite (Fig. 54C); bursal walls translucent with thin wrinkles where not sclerotized into bursal sclerite; gonocoxite 1 with 3–4 apical fringe setae, 6–7 smaller setae on medial surface (Fig. 55C); gonocoxite 2 subfalcate with tightly rounded apex, 2 lateral ensiform setae, apical nematiform setae on medioventral surface at 0.77× gonocoxite length.

Holotype

Male (BMNH) labeled: Mecyclothorax longulus Type D.S. Haleakala Perkins 120 // Type // Hawaiian Is. Perkins 1904-336. // Haleakala Maui 5000 ft. 6 IV 1894 // HOLOTYPE Mecyclothorax longulus Sharp J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat

M. longulus is known from Koa-‘Ōhi‘a Mesic Forest across a very limited geographic area west of Pu‘u o Kakae—elevations 1425–1615 m—in the Waikamoi area (Fig. 56). It was described by Sharp (1903) from a unique specimen from Ukulele Camp, and it has been recollected on four occasions since. It has been found in leaf siftate, by grubbing in leaf litter, under the rotten bark of Cheirodendron (‘ōlapa), and in a yellow-pan trap.

Mecyclothorax giffardi Liebherr

Figs 52D, 53G, 56

Mecyclothorax giffardi Liebherr 2005b: 108.

Diagnosis

Of the beetles comprising this taxonomic group, only individuals of this species simultaneously exhibit: 1, two dorsal elytral setae on interval 3 but no additional setae on intervals 5 or 7; 2, laterally convex elytra with the greatest width behind midlength in combination with slightly narrowed humeri, MEW/HuW = 1.98; and 3, moderately smaller body size, standardized body length 4.5–4.9 mm. The dorsal body surface is reflective due to largely transverse microsculpture: 1, vertex and pronotal disc covered with a distinct transverse mesh, sculpticell breadth subequal to twice sculpticell length; and 2, elytra with a transverse mesh, sculpticell breadth 2–3× length. Only the pronotal median base exhibits the upraised isodiametric sculpticells–irregularly swirling based on the orientation of the cuticular surface–characteristic of other species in the group. Setal formula 2 2 2 2.

Identification

(n = 2). The eyes are smaller, covering only ¾ of the protruded ocular lobe, and narrowly convex, ocular ratio = 1.41–1.42. The forebody is narrower relative to the elytra than in the other species with only the 2 dorsal elytral setae; MEW/MWH = 2.14, MEW/MPW = 1.46. The discal elytral striae are minutely punctate, and the dorsal elytral setae are in broad, foveate depressions that span interval 3 plus the adjacent halves of intervals 2 and 4. The forebody is distinctly darker than the elytra, with frons and vertex plus pronotal disc rufopiceous, contrasted to the rufobrunneous elytra. The apex of the elytral sutural stria and the adjoining elytral apex are paler, rufoflavous. Like related species, the femora are flavous with a basal piceous cloud, and the tibiae are rufobrunneous with a more pronounced piceous cast apically.

Male genitalia (n = 1). Aedeagal median lobe gracile, distance from parameral articulation to tip 4.1× depth at midlength (Fig. 53G); apex broadly expanded with flat apical face, the ventral tip rightly rounded; internal sac short and broad, with broad dorsal ostial microtrichial patch at base, and ventral surface broadly spiculate as a ventral patch; flagellar plate short, length 0.30× parameral articulation-tip distance.

Holotype

Male (BPBM) dissected and designated by Liebherr (2005b: 109). Type locality is: HI: Maui, Haleakalā, Polipoli Springs area, 5000 ft. el.

Distribution and habitat

M. giffardi is known from only two specimens, the holotype collected by W.M. Giffard at 1525 m elevation in the Kula Forest Reserve below Polipoli Springs, and a second male specimen collected by P.D. Krushelnycky in the Kahikinui Forest Reserve on Haleakalā’s south slope (Fig. 56). The Kahikinui specimen was collected in koa-‘ōhi‘a leaf litter.

Mecyclothorax foveopunctatus sp. n.

Figs 53H, 56, 57A

Diagnosis

This along with M. sobrinus and M. consobrinus represent the large-bodied species of the group; in this species standardized body length 5.6 mm. This species differs from the other two by the basally more constricted elytra (Fig. 57), and more punctate discal elytral striae, the striae themselves deeper and more regular. The pronotal median base is more discretely punctate, with ~ 6 distinct, rounded punctures plus 3–4 longitudinal wrinkles each side. The male aedeagal median lobe (Fig. 53H) lacks the robust, accessory subapical projection shared by males of M. consobrinus and M. sobrinus (Fig. 58). Setal formula 2 2 2 2.

Figure 58.

Male aedeagus, M. sobrinus group species (for abbreviations see Table 2, p. 23). A–C M. consobrinus. A Right view (Polipoli, 1890 m) B Right view, sac everted (Polipoli, 1500 m) C Ventral view (Polipoli, 1890 m) D–F M. sobrinus D Right view (Ukulele Camp Pipeline, 1540 m) E Right view (nr. Ukulele Camp, 1615 m) F Ventral view (Ukulele Camp Pipeline, 1540 m).

Description

(n = 1). Head capsule with frontal grooves deep near clypeus, angled laterally at midpoint to terminate mesad anterior supraorbital setae; dorsal impression of neck slightly concave; eyes moderate in size and convexity, ocular ratio = 1.44, ocular lobe ratio = 0.76; labral anterior margin moderately emarginate; antennae filiform, antennomeres 2–3 with sparse pelage of short setae; mentum tooth with sides right, apex broadly rounded. Pronotum transverse, MPW/PL = 1.33, broad basally, MPW/BPW = 1.36, hind angles obtuse, little projected, with lateral margins subparallel for short distance anterad angles; basal margin straight medially, extended slightly between laterobasal depressions; median longitudinal impression shallow, finely incised at depth, extended onto median base; anterior transverse impression deep, finely incised at depth, anterior callosity elevated, flat, both crossed by longitudinal wrinkles; front angles projected, rounded; pronotal base broader than apex, APW/BPW = 0.90; lateral marginal depression broad at front angle, moderately narrow at midlength, broadened near laterobasal depression, edge upturned; laterobasal depression broad, smooth, with median tubercle. Proepisternum with 5 minute punctures along hind marginal groove; prosternal process medially depressed, margin upraised with bead only anterad procoxae. Elytra subovoid, disc flat, sides abruptly sloped; basal groove slightly recurved to subangulate humeral angle; humeri narrowed, MEW/HuW = 1.90, lateral margin narrowly curved posterad outside angle; parascutellar seta present; parascutellar striole smooth anteriorly, 3 punctures posteriorly near apex; sutural interval of same convexity as lateral intervals basally, upraised as a callous apically; sutural and 2nd striae of subequal depth from base to apex; 8th interval convex laterad 7th stria near subapical sinuation, 7th stria and nearby portion of 7th interval depressed just apicad diminution of interval 6 at fusion of intervals 5 + 7; 2 dorsal elytral setae at 0.34× and 0.64–0.67× elytral length, setae in foveate depressions that span interval 3 plus lateral half of interval 4; apical and subapical setae present; lateral elytral setae arranged in anterior series of 7 setae, posterior series of 6 setae; elytral marginal depression moderately narrow throughout length, beadlike near subapical sinuation. Mesepisternum with ~18 punctures in 3 rows; metepisternal width to length ratio 0.86. Abdomen with irregular lateral wrinkles on ventrites 1–5; suture between ventrites 2 and 3 complete; apical male ventrite with 2 marginal setae. Legs-metatarsomere 1/metatibial length ratio = 0.18; metatarsomere 4 length along outer lobe 1.3× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci moderately deep, basal tarsomeres medially convex. Microsculpture of vertex upraised isodiametric sculpticells in transverse rows; pronotal disc with isodiametric sculpticells in transverse rows to a transverse mesh, sculpticell breadth 2× length, median base with granulate isodiametric mesh; elytral disc with upraised isodiametric sculpticells, the apex with upraised transverse mesh, sculpticell breadth 2× length; metasternum with distinct transverse mesh; laterobasal abdominal ventrites with swirling transverse and isodiametric microsculpture. Coloration of vertex dark rufobrunneous; antennomere 1 flavous, antennomeres 2–3 rufoflavous, 4–11 rufobrunneous; pronotal disc dark rufobrunneous, margins rufoflavous mesad front angles, lateral marginal depressions and median base rufobrunneous; proepipleuron rufoflavous, proepisternum rufopiceous; elytral disc rufobrunneous, sutural interval concolorous basally, slightly paler, rufoflavous apically; elytral marginal depression and apex slightly paler than disc, rufoflavous; elytral epipleuron flavous dorsally, rufobrunneous on ventral margin, metepisternum piceous; abdomen piceous, apical 1/5 of apical ventrite 6 flavous; metafemur with ground color flavous, basal half with broad piceous cloud; metatibia rufoflavous with piceous cast.

Male genitalia (n = 1). Aedeagal median lobe (Fig. 53H) much like a more robust version of M. longulus (Fig. 53E), gracile, distance from parameral articulation to tip 4.1× depth at midlength, apex extended 3× depth beyond apex of ostial opening, expanded dorsoventrally at tip, with apical face of tip obliquely flattened; internal sac unornamented, flagellar plate short, length 0.30× parameral articulation-tip distance.

Holotype

Male (CUIC) dissected and labeled: HI: Maui Haleakala / Waikamoi N.C.P. Ukulele / Pipeline 7-V-1998 lot 03 / 1495-1525m el. under / logs J.K. Liebherr // Hawaiian Is. / Perkins / 1904–336. / HOLOTYPE / Mecyclothorax / foveopunctatus / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Etymology

The Latin adjectival foveopunctatus signifies the foveate depressions surrounding the dorsal elytral setae.

Distribution and habitat

M. foveopunctatus is known only from the holotype collected under an ‘ōhi‘a log in mesic forest near Ukulele Pipeline (Fig. 56). The type specimen was collected along with specimens of M. cognatus, M. consanguineus, M. cymindicus, M. filipoides, M. multipunctatus, and M. sobrinus.

Mecyclothorax consobrinus Liebherr

Figs 54D, 55D, 57B, 58A–C, 59

Mecyclothorax consobrinus Liebherr 2005b: 101.

Diagnosis

This and M. sobrinus share the conditions of subquadrate elytra with dorsal setae restricted to interval 3 (Fig. 57B–C), and large body size; in this species standardized body length 5.8–6.3 mm. The two species are considered adelphotaxa based on shared possession of a very distinctive male aedeagal median lobe that exhibits a robust, apically directed process situated immediately basad the ostial opening (Fig. 58). Mecyclothorax consobrinus can be diagnosed by the more developed dorsal microsculpture: 1, vertex with upraised isodiametric sculpticells in transverse rows; 2, pronotal disc with upraised slightly transversely stretched sculpticells, pronotal median base with granulate isodiametric and transverse sculpticells; 3, elytral disc with upraised isodiametric mesh, the apex with isodiametric mesh and swirling transverse mesh in large depression associated with 7th stria. The elytra are also more irregularly depressed in this species, in some individuals due to presence of a third dorsal elytral seta in interval 3 (Fig. 57B), and in all individuals due to the deep and irregular depression associated with the fused apical portion of striae 5 + 7, this depression in some instances also involving the apical termination of interval 6. Setal formula 2 2 2-3 2.

Identification

(n = 5). The elytral striae are shallow, with the surfaces of the discal intervals irregularly undulated along their length. These undulations in concert with the upraised microsculpture lead to a satiny appearance to the elytral cuticle. The pronotal median base tends to have an irregular surface as well, due to the presence of distinct punctures in company with many longitudinal wrinkles. The mesepisternum is profoundly punctate in this species, with ~22 punctures arrayed in 2–3 longitudinal rows across its surface. Access to a male will cement the identification of male members of a series representing this species (Fig. 58A–C) (see below).

Male genitalia (n = 2). Aedeagal median lobe heavily sclerotized yet shaft dimensions gracile relative to length, distance from parameral articulation to tip 4.6× depth at midlength (Fig. 58A); apex broadly flattened along apical face, adze-shaped, along with large dorsal subapical projection at basal margin of ostium (a character shared only with M. sobrinus; Fig. 58D–E) that results in a paired structure surrounding the ostium that appears not unlike a bottle opener; median lobe with apex curved rightward in ventral view, the dorsal subapical projection curved leftward (Fig. 58C); internal sac very small, short, length 0.47× parameral articulation-tip distance, sac surface unornamented; flagellar plate very small, sclerotized ventral surface 0.24× parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix broad, columnar, apex rounded, ventral surface dorsad bursa copulatrix-common oviduct juncture with brownish coloration, lightly sclerotized, length 0.95 mm, breadth 0.46 mm (Fig. 54D); bursal walls translucent with thick wrinkles; gonocoxite 1 with 3–4 apical fringe setae, 1–2 thick, curved setae at apicomedial angle, and 4–5 smaller setal on medial surface (Fig. 55D); gonocoxite 2 narrowly subtriangular with narrowly rounded apex, base broadly extended laterally, 2 lateral ensiform setae, apical nematiform setae on medioventral surface at 0.65× gonocoxite length.

Holotype

Male (BPBM) designated by Liebherr (2005b: 107). Type locality is HI: Maui, Haleakala, Polipoli Springs area, 5000 ft. el.

Distribution and habitat

M. consobrinus is known only from the Polipoli Springs area along the southwest rift of Haleakalā (Fig. 59). It has been collected from leaf litter, the sift samples often taken from areas covered with Dryopteris wallichiana (Laukahi) ferns. It is also commonly found under stones on moist ground, and one specimen was found under loose Pinus radiata bark.

Figure 59.

Recorded geographic distributions of M. sobrinus group species.

Mecyclothorax sobrinus Sharp

Figs 54E, 55E, 57C, 58D–F, 59

Mecyclothorax sobrinus Sharp 1903: 253; Britton 1948b: 143.

Diagnosis

Individuals of this species exhibit overlapping head, prothoracic, and elytral ratios and standardized body length—5.5–6.6 mm—with M. consobrinus, reducing any diagnosis of the two species to qualitative characters associated with elytral setation and punctation, and cuticular microsculpture. The discal elytral striae are deeper and of more uniform depth in this species than in M. consobrinus. Striae 1–6 are closely punctured in the basal 2/3 of their length. The setal impressions associated with the two dorsal elytral setae are shallower and less broad than seen in M. consobrinus, depressing interval 3 plus less than half of interval 4. Also, the apical depression associated with interval 7 is shallower and more regularly depressed among individuals of this species. Finally, the microsculpture is less upraised overall: 1, vertex with well-developed isodiametric sculpticells in transverse rows; 2, pronotal disc with well-developed slightly transversely stretched mesh, the median base covered with a mixture of isodiametric and transverse sculpticells; 3, elytral disc with a transverse mesh, sculpticell breadth 2× length, apex with mesh more transverse, breadth 2–3× length. Also, no individuals representing this species have been observed to have more than two dorsal elytral setae. Setal formula 2 2 2 2.

Identification

(n = 5). Although the ratios overlap with M. consobrinus, eyes tend to be less developed in individuals of this species; ocular ratio = 1.37–1.46 versus 1.41–1.46 in M. consobrinus, ocular lobe ratio = 0.71–0.77 versus 0.74–0.76. The pronotal median base is relatively smooth, with only sparse fine punctures and a few longitudinal wrinkles. The pronotal lateral marginal depression is only slightly broader at the front angles, the angles tightly rounded. The mesepisternum is moderately punctate, with ~9 punctures in 1–2 longitudinal rows. Finally, the male median aedeagal lobe has a less developed dorsal projection and narrower, more rounded apex (Fig. 58D–F) than that of the adelphotaxon’s males.

Male genitalia (n = 2). Aedeagal median lobe (Fig. 58D) a slightly less exaggerated version than that characterizing M. consobrinus (Fig. 58A), distance from parameral articulation to tip 4.2× depth at midlength, apex broadly rounded in company with blunt, broad dorsal projection, the dorsal projection varying in curvature and apical shape (Fig. 58D–E), apex of median lobe curved rightward, dorsal projection curved leftward (Fig. 58F).

Female reproductive tract (n = 1). Bursa copulatrix broad, columnar apex rounded, ventral surface dorsad bursa copulatrix-common oviduct juncture with brownish coloration, lightly sclerotized, bursal length 1.0 mm, breadth 0.51 mm (Fig. 54E); bursal walls translucent with thick wrinkles outside area of sclerotization; gonocoxite 1 with 3–4 apical fringe setae, thicker apicomedial seta present at apical angle, 7–8 smaller setae basally along median margin (Fig. 55E); gonocoxite 2 narrowly subtriangular with tightly rounded apex, base broadly extended laterally, 2 lateral ensiform setae, apical nematiform setae on medioventral surface at 0.71× gonocoxite length.

Lectotype

Male (BMNH) hereby designated, labeled: Mecyclothorax sobrinus Type D.S. Haleakala Perkins 350 // Type // Hawaiian Is. Perkins 1904-336. // Haleakala Maui 4500 ft. Perkins 28 III 1894 // LECTOTYPE Mecyclothorax sobrinus Sharp J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat

M. sobrinus inhabits mesic forest west of Waikamoi Gulch (Fig. 59) from 1280–1980 m elevation. E.C. Zimmerman collected two specimens by beating at 6000–6500 ft. elevation on the NW upper slope; these specimens representing outliers to modern collections in the Koa-‘Ōhi‘a Mesic Forest near Ukulele Pipeline. Forest-inhabiting specimens have been found in sifted litter associated with ‘ōhi‘a and Cibotium (hāpu‘u) tree fern. The largest collections have come from yellow-pan traps set in ecotone forest situations (vi-viii-2006, L. Leblanc, UHIM).

Mecyclothorax ovipennis species group

Diagnosis. Species classified in this group are characterized by: 1, lateral elytral striae, at least interval 7, reduced in depth relative to the more medial striae; 2, the sutural and 2nd striae of subequal depth at the elytral apex; and 3, eyes well developed, the outer surface convex. This last character is broadly defined, with ocular ratios in Haleakalā species ranging 1.41–1.61, and ocular lobe ratios spanning 0.75–0.89. Beetle bodies of the included species appear gracile, with a basally constricted pronotum and gracile legs. Body size is small to moderate; standardized body length 3.3–4.9 mm. The elytra vary in shape, from subquadrate, to subovoid, to ellipsoid. Dorsal microsculpture also varies dramatically among the species placed here, with elytral disc microsculpture, for example, ranging from a distinct or shallow isodiametric mesh to a transverse mesh, to even a glossy surface with microsculpture apparent only on the lateral elytral intervals. As per the characters listed above, there is great disparity in setal formula across this assemblage, including 2 2 2 2, 2 2 2 1, 2 1 2 1, 2 1 2 0, and 2 1 1 0. When there is only one seta at the elytral apex, it may be the subapical seta or the apical seta.

Membership and distribution. This group comprises 37 species from across Maui Nui and Hawai‘i Island, or 15% of the entire Hawaiian Mecyclothorax fauna. The group is represented on Maui with the 19 Haleakalā species treated below plus four others in West Maui (Liebherr 2011). Species representation on the other islands include nine species on Moloka‘i (Liebherr 2007), one species on Lāna‘i (Liebherr 2009b), and four species on Hawai‘i Island (Liebherr 2008b). Species on different islands are characterized by identical setal formulae—e.g., West Maui, Haleakalā, and Hawai‘i house species with 2 2 2 2, and on Haleakalā and Moloka‘i reside species exhibiting 2 2 2 1[ae] and 2 1 2 0 setal patterns. Two of these species include the cryptic sibling species pair M. ovipennis Sharp of Haleakalā and M. ferovipennis Liebherr of West Maui, both of which fit the 2 2 2 2 setal formula. Conversely, the only three species characterized by the setal formula 2 1 2 2 reside in West Maui; M. exilioides Liebherr, M. allostriatus Liebherr, and M. geminatus Liebherr. To the degree that setal formula is congruent with phylogenetic relationships—in the triplet above, M. allostriatus and M. geminatus are cryptic sibling species—the diversification history of M. ovipennis group species was biogeographically complex, involving both within- and between-volcano speciation events. Therefore elucidating their collective history will require comprehensive phylogenetic analysis.

Key to adults of the Mecyclothorax ovipennis species group, Haleakalā volcano, Maui, Hawai‘i

1 Elytral disc piceous, contrasted with flavous lateral intervals 7–9 or 8–9, the lateral flavous band extended from humerus to apex (Fig. 60A–C) 2
1’ Elytral intervals 2–9 concolorous basally, rufous to piceous, with at most apex contrastedly flavous, lateral marginal depression outside stria 9 may be flavous (Figs 60D, 65, 68, 73, 78) 4
2(1) Pronotal hind angles slightly obtuse due to rounded hind margin, lateral margins divergent very close to angles (Fig. 60B–C); vertex with shallow transverse-mesh microsculpture, the surface glossy 3
2’ Pronotal hind angles right, lateral margins parallel before angles (Fig. 60A); vertex with distinct isodiametric sculpticells arranged in transverse rows (043) M. subtilis Britton & Liebherr, sp. n.
3(2) Elytra narrowly flavous marginally, intervals 8–9 flavous versus piceous disc (Fig. 60B); discal elytral intervals with shallow transverse-mesh microsculpture, the sculpticells not visible in areas of reflected light, the surface appearing glossy (044) M. patulus sp. n.
3’ Elytra more broadly flavous marginally, interval 6 slightly fuscous and intervals 7-9 flavous (Fig. 60C); discal elytral intervals with evident transverse-mesh microsculpture, the sculpticells visible in areas of reflected ligh (045) M. patagiatus sp. n.
4(1) Elytral striae 3–5 impunctate, discal striae may be developed or evanescent, and striae 1–2 may be indistinctly punctate near base 5
4’ Elytral striae 3–5 indistinctly to markedly punctate on disc, striae may be well developed or evanescent, if evanescent always indicated by a line of punctures 9
5(4) Pronotal lateral margins parallel or convergent anterad hind angles which are right to acute (Figs 60D, 65A) 6
5’ Pronotal lateral margins divergent anterad hind angles which are obtuse (Figs 65B–D, 68, 73, 78) 7
6(5) Elytra narrow relative to forebody, MEW/MHW = 1.96–2.0; elytral basal groove recurved anteriorly to join lateral marginal depression, the humerus subangulate (Fig. 60D) (046) M. strigosus sp. n.
6’ Elytra broad relative to forebody, MEW/MHW = 2.08–2.24; elytral basal groove not recurved anteriorly, juncture with lateral marginal depression rounded (Fig. 65A) (047) M. ovipennis Sharp
7(6) Vertex with evident isodiametric to transverse-mesh microsculpture, the sculpticell margins visible in reflected light 8
7’ Vertex and pronotal disc with obsolete transverse-mesh microsculpture, the surface glossy in reflected light (048) M. takumiae sp. n.
8(7) Pronotal base moderately constricted, MPW/BPW = 1.46–1.54; elytral basal groove evenly curved at humerus, elytral lateral marginal depression narrow posterad humerus (049) M. apicalis (Sharp) (in part)
8’ Pronotal base broad, MPW/BPW = 1.41–1.45; elytral basal groove curved anterad at humerus, the juncture of basal groove and lateral marginal depression indicated by a hitch, elytral lateral marginal depression broader, flavous posterad humerus (050) M. parapicalis sp. n.
9(4) Elytra broadly ellipsoid, lateral margins markedly convex and humeri narrowly rounded, MEW/HuW = 2.23–2.51 (Figs 68A–B) 10
9’ Elytra broader basally, lateral margins subparallel to convex, but humeri not constricted, MEW/HuW = 1.84–2.18 (Figs 68C, 73, 78) 11
10(9) Vertex and pronotal disc with evident transverse-mesh microsculpture, sculpticell breadth 2–3× length; male aedeagal median lobe apex broadly rounded (Fig. 69) (051) M. mauiae sp. n.
10’ Vertex with elongate transverse-mesh microsculpture, sculpticell breadth 3–4× length, pronotal disc covered with indistinct transverse microsculpture, much of the surface glossy; male aedeagal median lobe apex narrow with pointed tip (Fig. 70A–C) (052) M. subternus sp. n.
11(9) Pronotal lateral margins parallel or convergent anterad right or acute hind angles (Figs 68C, 73A–C) 12
11’ Pronotal lateral margins divergent anterad obtuse hind angles (Figs 73D, 78) 15
12(11) Eyes moderately convex, ocular ratio = 1.41–1.50 (Fig. 73A–C); elytra ellipsoid, lateral margins more evenly curved so that elytra are widest at middle or in anterior half; abdominal ventrites 4–6 concolorous with or only slightly paler than basal ventrites 13
12’ Eyes convex, ocular ratio = 1.51–1.56 (Fig. 68C); elytra obovoid, widest behind middle; abdominal ventrites 4–6 flavous, contrasted to piceous basal ventrites (053) M. flaviventris sp. n.
13(12) Elytra broad, lateral margins convex (Fig. 73B–C), MEW/HuW = 2.11–2.16; discal elytral intervals with transverse-mesh microsculpture 14
13’ Elytra narrow, elongate (Fig. 73A), MEW/HuW = 2.02–2.06; discal elytral intervals with well-developed isodiametric microsculpture (054) M. laetus Sharp
14(13) Elytral striae 1–2 moderately impressed, striae 3-6 progressively shallower, strial punctation indistinct especially on lateral striae (Fig. 73B); male aedeagal median lobe apex short and broad, with minute nipplelike protuberance (Fig. 76A) (055) M. cordaticollis (Blackburn)
14’ Elytral striae 1–4 impressed, distinctly punctate, striae 5–6 shallower with less evident punctures (Fig. 73C); male aedeagal median lobe narrowly extended distad ostium, the narrowly rounded tip bent downward (Fig. 76C) (056) M. cordaticollaris sp. n.
15(11) Pronotal lateral seta present, basal seta absent, the hind angles glabrous 16
15’ Both pronotal lateral and basal setae present, the pronotum quadrisetose (if basal seta appears absent, articulatory socket will be visible) 17
16(15) Vertex with well-developed isodiametric sculpticells arranged in transverse rows, pronotal disc with isodiametric to slightly transverse sculpticells in transverse rows; pronotal base broader, MPW/BPW = 1.46–1.54 (Fig. 65C) (049) M. apicalis (Sharp) (in part)
16’ Vertex with shallow transverse-mesh microsculpture, sculpticell breadth 2–3× length, pronotal disc with obsolete transverse-mesh microsculpture, glossy medially; pronotal base narrower, MPW/BPW = 1.58–1.69 (Fig. 73D) (057) M. subconstrictus (Sharp)
17(15) Pronotal hind angle defined by small but distinct toothlike projection, the lateral margin briefly sinuate before the obtuse angle (Fig. 78B–D) 18
17’ Pronotal hind angles rounded, not projected (Fig. 78A) (058) M. nubicola (Blackburn)
18(17) Pronotal base broader (Fig. 78C–D), MPW/BPW = 1.42–1.51; elytra subquadrate, lateral margins straighter posterad humeri 19
18’ Pronotal base narrower (Fig. 78B), MPW/BPW = 1.54; elytra subellipsoid, lateral margins evenly convex posterad the broadly rounded humeri (059) M. krushelnyckyi sp. n.
19(18) Vertex with shallow but evident transverse-mesh microsculpture, sculpticell breadth 2–3× length; elytra more quadrate, MEW/HuW = 1.84–1.90; elytral striae not impressed, indicated by series of isolated punctures (060) M. pusillus Sharp
19’ Vertex with obsolete transverse-mesh microsculpture, the surface glossy; elytra subquadrate, MEW/HuW = 1.98–2.19; elytral striae 1–4 impressed, the punctures connected by striae, stria 5 consisting of isolated punctures (061) M. rusticus Sharp

Mecyclothorax subtilis Britton & Liebherr, sp. n.

Figs 60A, 64

Mecyclothorax n. sp. α, Liebherr 2004, fig. 4.

Diagnosis

This is one of three species in the group that is characterized by bicolored elytra; the lateral elytral intervals flavous, contrasted to the piceous disc (Fig. 60A–C). In this species intervals 7–9 and the apex of the sutural stria are rufobrunneous to flavous, whereas the basal portions of intervals 2–5 are rufopiceous. The dorsal surface of the head and the pronotum are rufous with a flavous cast. The pronotum is moderately transverse, MPW/PL = 1.26, and basally constricted, MPW/BPW = 1.58. The dorsal surface of the head bears well-developed isodiametric sculpticells arranged in transverse rows. The setal formula is 2 1 2 0; the other two bicolored species—M. patulus and M. patagiatus—are characterized by presence of the subapical seta. Moreover, this species lacks the parascutellar seta, whereas it is present in the other two species. Standardized body length 3.45 mm.

Figure 60.

Mecyclothorax ovipennis group species, dorsal habitus view. A M. subtilis (nr. Ukulele Camp, 1525 m) B M. patulus (Waikamoi, 1305 m) C M. patagiatus (Kuhiwa E rim, 900 m) D M. strigosus (Kīpahulu W rim, 1850 m).

Description

(n = 1). Head capsule with frontal grooves broad near clypeus, convexity present laterad groove, a narrow carina extended to supraorbital seta; dorsal surface of neck flat; eyes large, moderately convex, ocular ratio = 1.46, ocular lobe ratio = 0.84; labral anterior margin very shallowly emarginate medially; antennae filiform, antennomeres 2–3 glabrous except for 1 or 2 small setae on shafts; mentum tooth with sides acute, apex tightly rounded. Pronotum with glabrous hind angles, the base constricted, and lateral margins subparallel anterad the right, projected hind angles; median base moderately depressed, strigose due to long punctures and wrinkles; basal margin straight medially, margin expanded posterad laterobasal depressions; median longitudinal impression shallow, finely incised; anterior transverse impression shallow, broad, crossed by indistinct wrinkles; anterior callosity elevated, flat, crossed by indistinct longitudinal wrinkles; front angles projected, tightly rounded; pronotal apex broader than base, APW/BPW = 1.06; lateral marginal depression narrow, edge slightly upturned, broader at front angle, beaded anterad basal sinuation; laterobasal depression smooth, continuous with lateral depression; slight tubercle mesad lateral margin. Proepisternum with 5 minute punctures along hind marginal groove; prosternal process with narrow median impression, lateral margins broadly beaded between coxae. Elytra subellipsoid, disc flat, sides moderately sloped; basal groove slightly recurved to tightly rounded humeral angle; greatest width near midlength, MEW/HuW = 2.09; parascutellar striole discontinuous along length, with 3–4 punctures; sutural interval coplanar with lateral striae basally, upraised in apical half; sutural and 2nd striae of subequal depth from base to apex; discal striae 1–5 broad but defined, lined with minute elongate punctulae in basal 1/3 of length, 6–7 discontinuous, represented by serial punctures, discal intervals moderately convex; 8th interval slightly more convex than fused apical portion of fused striae 5 + 7; 2 dorsal elytral setae at 0.28× and 0.64× elytral length, setal impression small, spanning 1/3–1/2 of interval 3; apical and subapical setae absent; lateral elytral setae arranged in an anterior series of 6 setae and a posterior series of 5 setae; elytral marginal depression narrow, margin little upturned in basal half, narrowly beadlike near subapical sinuation; subapical sinuation very shallow, nearly obsolete. Mesepisternum with ~8 punctures in 1–2 rows; metepisternal width to length ratio = 0.71; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1–5; suture between ventrites 2 and 3 complete; apical female ventrite with 4 equally spaced marginal setae plus median trapezoid of 4 subequal, short setae. Legs-metatarsomere 1/metatibial length ratio = 0.20; metatarsomere 4 length along outer lobe 1.33× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci narrow, shallow, median surface broad. Microsculpture of pronotal disc transverse mesh, sculpticell breadth 2× length, median base with mixture of isodiametric and transverse sculpticells; elytral disc with transverse mesh, sculpticell breadth 2–4× length, apex with shallow transverse mesh of the same dimensions; metasternum with shallow transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of antennomere 1 flavous, antennomeres 2–3 rufoflavous, 4–11 rufobrunneous; proepipleuron and proepisternum rufoflavous; elytral epipleuron rufoflavous, metepisternum rufobrunneous; abdomen with ventrites 1–3 medially pale rufobrunneous, lateral portions and ventrites 4–6 rufoflavous; femur rufoflavous; tibia rufoflavous with rufous cast.

Female reproductive tract. The lone female holotype was not dissected.

Holotype

Female (BPBM) labeled: Haleakala / 5000 ft. / April / RCLP (obverse of mounting platen) / 369 (on reverse of platen) // Type (round red-margined label) // sp. n. near M. ovipennis // 1323 // HOLOTYPE / Mecyclothorax / subtilis / E.B. Britton / det. 1940 // HOLOTYPE / Mecyclothorax / subtilis Britton / & Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Etymology

Britton’s choice of the Latin adjective subtilis to signify the minute, slender body of this beetle was extremely appropriate, and that choice is hereby validated.

Distribution and habitat

Perkins’ lot 369 was collected on 10-iv-1894 at 5000 ft. (1524 m) elevation (Anonymous N D). The only relevant field note from that day (Perkins, 1894) states “Picked up a good number of Carabids, …” As Perkins made no mention of straying far from camp, Ukulele Camp (Site) is designated the type locality (Fig. 64).

Mecyclothorax patulus sp. n.

Figs 60B, 64

Diagnosis

This second of the three bicolored species (Fig. 60B) exhibits more narrowly flavous elytral margins—only intervals 8–9—versus piceous discal intervals 2–7. The sutural interval is rufous basally, flavous apically. The bisetose pronotum is more transverse than that of M. subtilis; MPW/PL = 1.28, and less constricted basally, MPW/BPW = 1.53. As in the next species below, M. patagiatus, the parascutellar and subapical elytral setae are present, but the elytral humeri are narrower in this species—MEW/HuW = 2.06 versus 2.0—and the elytra more ellipsoid. The setal impressions of the dorsal elytral setae are larger in beetles of this species, as they span interval 3. Setal formula 2 1 2 1[sae]. Standardized body length 3.4 mm.

Description

(n = 1). Head capsule with frontal grooves broad near clypeus, a lateral carina extended to mesad anterior supraorbital seta; dorsal surface of neck flat; eyes moderately convex, ocular ratio = 1.47, not extended onto posterior portion of ocular lobe, ocular lobe ratio = 0.75; labral anterior margin broadly emarginate to 1/6 of length; antennae filiform, sparse setae on apex of antennomere 1 and shafts of antennomeres 2–3; mentum tooth with sides acute, apex tightly rounded. Pronotum transverse, MPW/PL = 1.28, bisetose, glabrous hind angles obtuse, rounded behind, lateral margin subparallel for short distance anterad angle; base moderately broad, MPW/BPW = 1.53; median base nearly coplanar with disc, ~10 sparsely distributed, isolated punctures each side; basal margin convexly expanded between laterobasal depressions; median longitudinal impression shallow, finely incised, crossed by fine longitudinal wrinkles; anterior transverse impression deep, finely incised, minute irregularities in deepest part; anterior callosity convex, glossy surface with minute longitudinal wrinkles; front angles slightly projected, tightly rounded; pronotal apical width greater than basal width, APW/BPW = 1.10; lateral marginal depression narrow, edge upturned, slightly broader at front angle; laterobasal depression with slightly irregular surface, continuous with lateral depression. Proepisternum with 5 minute punctures along hind marginal groove; prosternal process with narrow median impression, lateral margins broadly beaded between coxae. Elytra broadly subellipsoid, disc flat, sides moderately sloped; basal groove evenly and distinctly recurved to tightly rounded humeral angle, MEW/HuW = 2.06; parascutellar seta present; parascutellar striole with 3–4 punctures, very shallow between punctures; sutural interval more convex than lateral intervals, sutural juncture upraised; sutural and 2nd striae of subequal depth from base to disc, 2nd stria slightly shallower at apex; discal striae 1–5 moderately broad, evident, stria 6 shallower and stria 7 shallower still, interrupted along length; striae 1–4 with minute elongate punctures, stria 5 with shallower punctures and stria 6 with only irregularities along length; intervals 2–5 moderately convex, lateral intervals less so; 8th interval slightly more convex than fused apical portion of striae 5 + 7; 2 dorsal elytral setae at 0.28–0.32× and 0.62× elytral length, setal impressions evident, spanning interval 3; apical elytral seta absent, subapical elytral seta present; lateral elytral setae arranged as anterior series of 6 setae and posterior series of 5 setae; elytral marginal depression narrow, edge little upturned in basal half, margin beadlike near subapical sinuation; subapical sinuation very shallow, nearly obsolete. Mesepisternum with ~6 punctures in 1–2 rows; metepisternal width to length ratio = 0.80; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1–5, lateral depressions on ventrites 3–6; suture between ventrites 2 and 3 complete; apical female abdominal ventrite with 4 equally spaced setae plus trapezoid of 4 subequal, short setae. Legs-metatarsomere 1/metatibial length ratio = 0.20; metatarsomere 4 length along outer lobe 1.3× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci narrow, shallow, median surface broad. Microsculpture of vertex shallow isodiametric sculpticells in rows; pronotal disc with shallow transverse mesh, sculpticell breadth 3× length, to transverse lines not connected into mesh; pronotal median base glossy, obsolete transverse mesh between punctures; elytral disc and apex with shallow transverse mesh, sculpticell breadth 2–4× length; metasternum with transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous; antennomere 1 flavous, antennomeres 2–3 rufoflavous, 4–11 rufobrunneous; pronotal disc rufobrunneous with piceous cast, lateral margins, apex, and base rufoflavous; proepipleuron flavous, proepisternum rufobrunneous with piceous cast; elytral epipleuron dorsally flavous, ventrally rufoflavous, metepisternum rufobrunneous with piceous cast; abdomen with ventrites 1–2 medially, and 3–5 mediobasally rufopiceous, ventrites 3–6 apical and marginally rufoflavous; metafemur flavous; metatibia flavous with brunneous cast.

Female reproductive tract. The lone female holotype was not dissected.

Holotype

Female (NMNH) labeled: HI:Maui Koolau / F.R. Kula Pipeline Rd. / N20°48.58', W156°14.30', / 18-V-2003 lot09 el. 1305m / pyr. fog log D.A. Polhemus // HOLOTYPE / Mecyclothorax / patulus / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Etymology

The Latin adjective patulus means open, spread out, or broad (Brown 1956), signifying the short, broad body of these beetles.

Distribution and habitat

M. patulus is known only from an ‘Ōhi‘a Wet Forest site uphill from the junction of the Kula Pipeline and Waikamoi Flume Roads (Fig. 64). The type specimen was found in a pyrethrin fog sample of a downed ‘ōhi‘a log covered with moss.

Mecyclothorax patagiatus sp. n.

Figs 60C, 61A–B, 64

Diagnosis

This, the third Haleakalā M. ovipennis group species to display bicolored elytra (Fig. 60C), can be diagnosed by the following combination: 1, discal elytral striae 1–6 rufobrunneous with piceous cast, intervals 7–9 contrastedly rufoflavous; 2, pronotal disc also rufobrunneous with piceous cast, pronotal margins rufoflavous; 3, parascutellar seta present; 4, subapical elytral seta present, apical seta absent; 5, pronotal lateral margins slightly divergent from hind obtuse hind angles; 6, elytral humeri broadly rounded, the elytra broadly subquadrate, MEW/HuW = 2.0. Criteria 1, 5, and 6 diagnose this species from both M. subtilis and M. patulus, whereas criteria 2, 3, and 4 diagnose this species from M. subtilis. The pronotum of the unique holotype has the basal pronotal seta present on the right side, with the left hind angle glabrous (specimen examined at 125×), obviating use of this character in the diagnosis. Setal formula 2 1-2 2 1[sae]. Standardized body length 3.8 mm (slightly larger than both preceding species).

Description

(n = 1). Head capsule with frontal grooves broad near clypeus, lateral carina to anterior supraorbital seta; dorsal surface of neck flat; eyes moderately convex, ocular ratio = 1.43, ocular lobe ratio 0.78; labral anterior margin broadly emarginate to 1/6 of length; antennae filiform, antennomeres 2–3 with sparse pelage of short setae; mentum tooth with sides acute, apex tightly rounded. Pronotum transverse, MPW/PL = 1.30, base moderately constricted, MPW/BPW = 1.50; hind angle obtuse, margin behind rounded; median base moderately depressed, ~20 punctures or strigose wrinkles each side; basal margin convexly expanded between laterobasal depressions; median longitudinal impression evident, finely incised, joined by fine transverse wrinkles; anterior transverse impression deep, finely incised, minute irregularities in deepest part; anterior callosity elevated, flat, crossed by indistinct longitudinal wrinkles; front angles projected, broadly rounded; apical and basal pronotal widths subequal, APW/BPW = 1.03; lateral marginal depression moderate, edge upturned, broader at front angle; laterobasal depression narrowly concave, continuous with lateral depression. Proepisternum with 5 minute punctures along hind marginal groove; prosternal process narrowly impressed medially, lateral margins broadly beaded between coxae. Elytra with disc flat, sides moderately sloped; basal groove slightly recurved to broadly rounded humerus; parascutellar striole with 3–4 punctures, shallow between punctures; sutural interval coplanar with lateral intervals basally, upraised in apical half; sutural and 2nd striae of subequal depth and breadth from base to apex; discal striae 1–5 broad, deep, stria 6 shallower and more irregular, stria 7 shallower still; sutural stria deep, finely punctate basally, deep, narrow, and smooth apically; striae 2–4 with minute punctures on disc, punctures shallower in stria 5, linear irregularities in stria 6; discal intervals 2–4 convex, lateral intervals less so; 8th interval slightly more convex than fused apical portion of striae 5 + 7; 2 dorsal elytral setae at 0.27× and 0.54× elytral length, setal impressions small, spanning ½ width of interval 3; lateral elytral setae arranged in anterior series of 6 setae, posterior series of 5 setae; elytral marginal depression narrow, margin little upturned in basal half, beadlike near subapical sinuation; subapical sinuation very shallow, nearly obsolete. Mesepisternum with ~6 punctures in 1–2 rows; metepisternal width to length ratio = 0.80; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles in ventrites 1–5, lateral depressions in ventrites 3–6; suture between ventrites 2 and 3 complete; apical male ventrite with 2 marginal setae. Legs-metatarsomere 1/metatibial length ratio = 0.19; metatarsomere 4 length along outer lobe 1.3× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci narrow, shallow, median surface broad. Microsculpture of vertex with evident isodiametric sculpticells in transverse rows; pronotal disc with shallow transverse mesh, sculpticell breadth 3× length, to transverse lines; pronotal median base with shallow transverse mesh laterally, median area glossy; elytral disc with evident transverse mesh, sculpticell breadth 2–4× length, apex with more distinct transverse mesh of same dimensions; metasternum with transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous; antennomere 1 flavous, antennomeres 2–3 rufoflavous; 4–11 rufobrunneous; pronotal disc rufobrunneous with piceous cast, margins rufoflavous; proepipleuron rufoflavous, proepisternum rufobrunneous with piceous cast; elytral sutural interval concolorous with disc basally, rufoflavous apically; elytral epipleuron dorsally flavous, ventrally rufoflavous; metepisternum rufobrunneous; abdomen with ventrites 1–2 medially, 3–5 mediobasally rufopiceous, 3–6 apically and marginally rufoflavous, apical ventrite 6 with apical ¾ paler, flavous; metafemur flavous; metatibia flavous with brunneous cast.

Male genitalia (n = 1). Aedeagal median lobe robust, distance between parameral articulation and tip 3.2× depth at midlength (Fig. 61A); extension of apex beyond ostial opening parallel sided at base and evenly narrowed dorsoventrally to tightly rounded tip; median lobe curved sinuously leftward toward apex in ventral view, the right margin distinctly concave, left margin convex (Fig. 61B); internal sac without ornamentation, flagellar plate elongate, length of sclerotized plate 0.54× parameral articulation-tip distance.

Figure 61.

Male aedeagus, M. ovipennis group species (for abbreviations see Table 2, p. 23). A–B M. patagiatus right and ventral views (Kuhiwa E rim, 900 m) C–E M. ovipennis C Right view (Kopili‘ula, 1170 m) D Ventral view (Helele‘ike‘oha, 1615 m). E Ventral view (Kopili‘ula, 1170 m) F–H M. apicalis. F Right view (NW upper slope, 2745 m). G Right view, sac everted (summit, 2895–3050 m) H Ventral view (NW upper slope, 2745 m) I M. parapicalis, right view, sac everted (Holua Cabin, 2134 m).

Holotype

Male (CUIC) dissected and labeled: HI: E.Maui, Kuhiwa / 2950 ft.,10June1999 / Cibotium chamissois / Dead fronds // C. Ewing Coll. / 20°46'25˝N / 156°06'04˝W // HOLOTYPE / Mecyclothorax / patagiatus / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Etymology

The Latin stem for this species epithet is patagium; i.e. a gold edging or border (Brown 1956). The adjectival form patagiatus signifies the pale elytral border of beetles of this species.

Distribution and habitat

M. patagiatus is known from 900 m elevation in the Kuhiwa Valley of the Hanawī windward face of Haleakalā (Fig. 64). The type specimen was collected from dead Cibotium (hāpu‘u) tree fern fronds along with one specimen each of Bembidion haleakalae Liebherr, M. mauiae (Fig. 71), and M. bacrionis (Fig. 112).

Mecyclothorax strigosus sp. n.

Figs 60D, 62A, 63A, 64

Diagnosis

This species (Fig. 60D) plus M. ovipennis (Fig. 65A) and M. flaviventris (Fig. 68C) comprise the three species in this group with the largest, most convex eyes; ocular ratio = 1.55–1.57 in this species. Of these, both M. ovipennis and this species are characterized by impunctate discal striae 1–4. This species (Fig. 60D) can be told from M. ovipennis (Fig. 65A) by the narrower body with more basally constricted pronotum, MPW/BPW = 1.56–1.67, and more narrowly ellipsoid elytra. Moreover, this is the only one of the three with glabrous hind pronotal angles, and without any apical elytral setae; setal formula 2 1 2 0. Standardized body length 4.3–4.7 mm.

Description

(n = 2). Head capsule with frontal grooves broad near clypeus, lateral carina to anterior supraorbital seta; dorsal surface of neck flat; ocular lobe distinctly protruded from gena, eyes large, ocular lobe ratio = 0.79–0.80; labral anterior margin very shallowly emarginate medially; antennae filiform, antennomeres 2–3 with sparse pelage of short setae; mentum tooth with sides acute, apex broadly rounded. Pronotum appearing elongate, MPW/PL = 1.11–1.18; hind angle right, lateral margin straight, subparallel to slightly convergent anterad hind angle; median base only slightly depressed, ~15 densely distributed punctures each side extended to laterobasal depression; basal margin nearly straight across base; median longitudinal impression very shallow, finely incised; anterior transverse impression very shallow, broad, crossed by longitudinal wrinkles; anterior callosity nearly flat, crossed by indistinct wrinkles; front angles not projected, tightly rounded; pronotal apical width greater than basal width, APW/BPW = 1.09–1.16; lateral marginal depression very narrow throughout length, edge tightly upturned; laterobasal depression depressed, punctate surface continuous with median base. Proepisternum with 5 minute punctures along hind marginal groove; prosternal process with narrow median impression, lateral margins broadly beaded between coxae. Elytra with disc flat, sides steeply sloped to depressed lateral margins and apex; basal groove briefly, distinctly recurved to angulate humerus; parascutellar seta present; parascutellar striole with 4–5 punctures, shallow, continuous between punctures; sutural interval more convex than intervals 2–4, but sutural juncture still depressed; sutural stria shallow, with minute punctulae basally, slightly deeper and more well defined than 2nd stria on disc, the two of subequal depth apically; discal striae 2–4 shallow, smooth, striae 5–6 obsolete but traceable, stria 7 absent; discal intervals 2–4 only slightly convex to nearly flat, lateral intervals flat; 8th interval of similar convexity to fused apical portion of striae 5 + 7; 2 dorsal elytral setae at 0.30–0.31× and 0.61–0.66× elytral length, setal impressions very small, spanning 1/3 of interval 3; lateral elytral setae arranged in anterior series of 7 setae, and posterior series of 6 setae; elytral marginal depression narrow, margin upturned, beaded only at subapical sinuation; subapical sinuation shallow, more abruptly incurved anteriorly. Mesepisternum with ~7 punctures in 2 rows; metepisternal width to length ratio = 0.72; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1–3, lateral depressions on ventrites 3–6; suture between ventrites 2 and 3 reduced laterally, effaced; apical female ventrite with 4 equally spaced setae plus median trapezoid of 4 setae, the basal pair longer. Legs-metatarsomere 1/metatibial length ratio = 0.18; metatarsomere 4 length along outer lobe 1.25× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci narrow, shallow, median area broad. Microsculpture of vertex and pronotal disc a transverse mesh, sculpticell breadth 2–3× length; pronotal median base with transverse mesh, sculpticell breadth 2× length, between punctures; elytral disc and apex with isodiametric to transverse sculpticells, sculpticell breadth 2× length, in transverse rows; metasternum with distinct transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous; antennomere 1–3 flavous, 4–11 darker, more brunneous; pronotal disc rufobrunneous with piceous cast, the lateral margins moderately, and base and apex broadly, rufoflavous; proepipleuron rufoflavous, proepisternum rufobrunneous with piceous cast; elytral disc dark, rufobrunneous to rufopiceous; sutural interval rufobrunneous basally, flavous in apical 1/3; elytral intervals 7–9 slightly paler than disc, rufoflavous basally, flavous apically; elytral epipleuron flavous, metepisternum rufobrunneous with piceous cast; abdomen with ventrite 1 (plus metepimeron) rufobrunneous, ventrites 2–3 and middle of ventrites 4–5 rufopiceous; abdominal apical ventrite with apical 2/3 flavous; metafemur flavous; metatibia flavous with brunneous cast.

Female reproductive tract (n = 1). Bursa copulatrix columnar with apical expansion, length 1.0 mm, apical expansion breadth 0.46 mm, basal breadth 0.34 mm (Fig. 62A); bursal shaft translucent, thinly wrinkled, apex more transparent, less wrinkled; gonocoxite 1 with 3 apical fringe setae, the middle seta more robust, a larger seta at apicomedial angle and 12–13 smaller setae basally on medial surface (Fig. 63A); gonocoxite 2 falcate with subacuminate apex, base extended laterally as sinuous panhandle, 2 lateral ensiform setae, apical nematiform setae on medial surface at 0.75× gonocoxite length.

Figure 62.

Female bursa copulatrix and associated reproductive structures, M. ovipennis group species, ventral view (for abbreviations see Table 2, p. 23). A M. strigosus (Honomanu, 1860 m) B M. ovipennis (Kopili‘ula, 1170 m) C M. apicalis (summit, 2895–3050 m) D M. mauiae (Waikamoi, 1305 m) E M. mauiae (Waikamoi, 1310 m). F M. subternus (Kuhiwa, 1030 m) G M. flaviventris (Kuhiwa, 2070–2100 m) H M. laetus (Ukulele Camp Pipeline, 1495-1525 m) I M. cordaticollis (nr. Ukulele Camp, 1525 m) J M. cordaticollaris (Kaupō Gap, 1495 m) K M. subconstrictus (summit, 2895–3050 m) L M. pusillus (summit, 2895–3050 m). Scale bar = 0.50 mm.

Figure 63.

Left female gonocoxa, M. ovipennis group species, ventral view. A M. strigosus (Honomanu, 1860 m) B M. ovipennis (Kopili‘ula, 1170 m) C M. apicalis (summit, 2895–3050 m) D M. mauiae (Waikamoi, 1305 m) E M. subternus (Kuhiwa, 1030 m). F M. flaviventris (Kuhiwa, 2070–2100 m).

Holotype

Female (CUIC) labeled: HI: Maui Haleakala N.P. / Kipahulu west rim ESE / Kuiki, sift humus ex ohia / 15-V-1993 lot 02 / el. 1850 m / J.K. Liebherr & / A.C. Medeiros / Collectors // 2 // HOLOTYPE / Mecyclothorax / strigosus / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratype

Female (CUIC) dissected, with same label as holotype except “1” instead of “2.”

Etymology

The Latin adjectival strigosus, meaning thin, signifies the narrow body shape characteristic of this species.

Distribution and habitat

M. strigosus has only been encountered in ‘Ōhi‘a Montane Wet Forest ESE of Kuiki at 1850 m elevation (Fig. 64). The two specimens were found in a litter sample sifted from humus surrounding the bases of large ‘ōhi‘a trees. The forest also included Cheirodendron (‘ōlapa) and Leptecophylla tameiameiae (pūkiawe). The sample containing specimens of M. strigosus also included specimens of M. antaeus, M. consanguineus, M. mauiae, M. ovipennis, and M. pau.

Figure 64.

Recorded geographic distributions of M. ovipennis group species.

Mecyclothorax ovipennis Sharp

Figs 61C–E, 62B, 63B, 65A, 66

Mecyclothorax ovipennis Sharp 1903: 250; Britton 1948b: 145; Swezey 1954: 27, 53 (biology); Liebherr 2005b: 109.

Diagnosis

Among Haleakalā Mecyclothorax (Fig. 65A), this is most similar to the preceding, M. strigosus (Fig. 60D) based on the well-developed eyes, ocular ratio = 1.55–1.61 and ocular lobe ratio = 0.84–0.89, plus basally constricted pronotum and ellipsoid elytra. They can be separated by the setal conformation, with this species characterized by a quadrisetose pronotum, and presence of the apical elytral seta; setal formula 2 2 2 1[ae]. This species is characterized by the same setal formula as M. flaviventris, but individuals of that species exhibit punctate discal striae (Fig. 68C). Standardized body length 3.7–4.9 mm.

Figure 65.

Mecyclothorax ovipennis group species, dorsal habitus view. A M. ovipennis (Kīpahulu, 1800 m) B M. takumiae (Paliku, 1950 m) C M. apicalis (summit, 2895–3050 m) D M. parapicalis (Holua, 2135 m).

Identification

(n = 5). The pronotum is very cordate in this species, MPW/BPW = 1.46–1.59, with the lateral margin subparallel to convergent for 0.2× the pronotal length anterad the projected, right to acute hind angles. The pronotum appears elongate, but is actually slightly transverse; MPW/PL = 1.08–1.21. The surface of the pronotal disc, and anterior transverse impression and associated callosity are irregularly wrinkled. Of the elytral striae, only sutural stria 1 is moderately deep basally, with elongate punctures that expand the stria basally, the stria smooth and deep apically. Striae 2–4 are shallower on the disc, striae 5–7 progressively shallower, and striae 6–7 discontinuous. At the elytral apex, stria 2 is of subequal depth to the sutural stria, fused striae 3 + 4 and 7 are present, and the apices of striae 5 and 6 are shallow but traceable. The vertex bears isodiametric and transverse sculpticells in transverse rows, the transverse sculpticells 2–3× broad as long. The pronotal and elytral discs are covered with transverse-mesh microsculpture, sculpticell breadth 1.5–3× length; the pronotal base has a shallow transverse mesh between glossy portions of the cuticle.

Male genitalia (n = 8). Aedeagal median lobe gracile, distance between parameral articulation and tip 4× depth at midlength (Fig. 61C); apex well extended beyond apex of ostial opening, dorsal surface of projection broadly convex, then flattened dorsad tightly rounded tip, ventral margin slightly concave due to downward curvature of tip (Figs 61C–D); median lobe not curved in ventral view, though left margin distinctly incurved to apical extension, and right margin concave before apex (Fig. 61E); internal sac broader near flagellar plate, covered with well-developed pelage of microspicules, the spicules densest on ventral surface forming a poorly developed ventral ostial microtrichial patch (Fig. 61D); flagellar plate moderately elongate, length 0.42× parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix columnar, subdivided into broader basal portion and slightly narrower apical lobe, overall length 0.91 mm, breadth 0.31 mm (Fig. 62B); bursal walls diaphanous, very thin and with indistinct wrinkles; gonocoxite 1 with 4–5 apical fringe setae, a curved seta just basad apicomedial angle, and 8–10 smaller setae on medial margin, setae subequally divided between ventral and dorsal surfaces (Fig. 63B); gonocoxite 2 falcate with tightly rounded apex, base extended laterally into sinuous panhandle, 2 subequal lateral ensiform setae, apical nematiform setae on medial surface at 0.68× gonocoxite length.

Lectotype

Female (BMNH) designated by Liebherr (2005b: 110). Type locality Haleakala, 4500–6000 ft., III-1894 (R.C.L.P. lot 383; Anonymous N D).

Distribution and habitat

M. ovipennis is among the most broadly distributed Mecyclothorax species on Haleakalā (Fig. 66). It requires, at the minimum, mesic forest conditions, being isolated at Polipoli Springs on the Kula face. It occurs along the eastern margin of Haleakalā Crater where mesic forest occurs. It is also at home in wetter forest situations throughout Waikamoi, Hanawī, Hāna Bogs, Kīpahulu Valley, and the Manawainui Planeze. It has been collected in habitats ranging 880–2134 m elevation. It has been found in association with a great diversity of plant species, including ferns (Asplenium, Cibotium, Dicranopteris, and Sadleria), herbaceous secondarily woody shrubs (Coprosma, Cyanea, Myrsine, Rubus, and Vaccinium) and emergent trees (koa and ‘ōhi‘a). It is also commonly encountered in sifted litter.

Figure 66.

Recorded geographic distribution of M. ovipennis.

Mecyclothorax takumiae sp. n.

Figs 65B, 67

Diagnosis

Within the M. ovipennis group, this species (Fig. 65B) forms part of a triplet of species also including M. apicalis (Fig. 65C) and M. parapicalis (Fig. 65D) that are collectively diagnosed by glabrous, obtuse pronotal hind angles, shallow impunctate discal elytral striae, and concolorous elytral disc and margins. Of these, M. takumiae is characterized by the smallest body size, standardized body length 3.6 mm, and least developed microsculpture. The pronotal disc and median base are glossy with obsolete transverse-mesh microsculpture and parallel lines over portions of the cuticle, whereas the elytral disc has a shallow mesh of isodiametric and transverse sculpticells, breadth 2–3× length. Both M. apicalis and M. parapicalis have well-developed sculpticells covering those areas. Setal formula 2 1 2(1) 0; the right elytron has both dorsal elytral setae, whereas the left has only a seta at the anterior position of the right elytron. As the bisetose condition is shared with M. apicalis and M. parapicalis, the unisetose elytron is considered a variant.

Description

(n = 1). Head capsule with frontal grooves broad near clypeus, lateral carina to anterior supraorbital seta; dorsal surface of neck flat; eyes moderately developed, ocular ratio = 1.45, ocular lobe ratio = 0.80; labral anterior margin medially emarginate, medially excavated 1/6 of length; antennae filiform, antennomeres 2–3 with only 1 or 2 short setae on shafts; mentum tooth with sides acute, apex rounded. Pronotum slightly transverse, MPW/PL = 1.21, moderately constricted basally, MPW/BPW = 1.53; hind angle obtuse, margin behind rounded; median base markedly depressed versus disc, ~9 punctures each side, surface glossy between; basal margin convexly expanded between laterobasal depressions; median longitudinal impression shallow, finely incised, crossed by fine transverse wrinkles; anterior transverse impression narrow, shallowly incised laterally, obsolete medially; anterior callosity slightly convex, smooth, glossy; front angles not to slightly projected, tightly rounded; pronotal apical and basal width equal, APW/BPW = 1.0; lateral marginal depression narrow through apical 1/3 of length, edge upturned, widened in basal 1/3; laterobasal depression narrow, surface irregular, continuous with lateral depression. Proepisternum with 5 minute punctures along hind margin; prosternal process with narrow median impression, lateral margins broadly beaded between coxae. Elytra subquadrate, disc flat, sides distinctly sloped; basal groove evenly recurved to subangulate (left) to tightly rounded (right) humerus, MEW/HuW = 2.04; parascutellar seta present; parascutellar striole with 4 punctures, shallow between punctures; sutural interval slightly more convex than lateral intervals, upraised at sutural juncture; sutural stria shallow, continuous basally, punctate on disc, smooth and deep apically; striae 2–6 progressively shallower, smooth, stria 7 obsolete; stria 1 subequal to slightly deeper than stria 2 at elytral apex; elytral interval 2 slightly convex, intervals 3–7 progressively flatter; 8th interval subcarinate laterad fused apical portion of striae 5 + 7; 2 dorsal elytral setae at 0.31× and 0.63× elytral length (right elytron), setal impressions moderate, spanning 2/3 of interval 3; apical and subapical setae absent; lateral elytral setae arranged in anterior series of 6 setae and posterior series of 6 setae; elytral marginal depression slightly broader at humerus, narrowed laterally, beadlike at subapical sinuation; subapical sinuation shallow, more abruptly incurved anteriorly. Mesepisternum with ~8 punctures in 1–2 rows; metepisternal width to length ratio = 0.65; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1–6; suture between ventrites 2 and 3 complete; apical female ventrite with 4 equally spaced setae plus a median trapezoid of 4 subequal, short setae. Legs-metatarsomere 1/metatibial length ratio = 0.18; metatarsomere 4 length along outer lobe 1.33× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci narrow, shallow, median area broad. Microsculpture of vertex a shallow transverse mesh, sculpticell breadth 2–3× length; elytral apex with transverse mesh, sculpticell breadth 2–3× length; metasternum with transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous with piceous cast; antennomeres 1–3 flavous, 4–11 darker, more brunneous; pronotal disc rufopiceous, lateral margins concolorous, base and apex paler, rufoflavous; proepipleuron rufoflavous, proepisternum rufobrunneous with piceous cast; elytral disc rufopiceous, sutural interval rufous in basal half, flavous in apical half; 9th elytral interval and lateral marginal depression rufous, apex of intervals 8 and 9 flavous; elytral epipleuron dorsally flavous, ventrally rufoflavous, metepisternum rufopiceous; abdomen with ventrites 1–5 and the base of 6 rufopiceous, apical 1/3 of apical ventrite 6 flavous; metafemur flavous; metatibia flavous with brunneous cast.

Female reproductive tract. The lone female holotype was not dissected.

Holotype

Female (BPBM) labeled: HAWAII: Maui I. / Haleakala Crater / Paliku, 1950 m / 1 JUL 1998 // R. Takumi, coll. / HALE-RM / ex. pitfall trap // HOLOTYPE / Mecyclothorax / takumiae / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Etymology

Raina Takumi Kahaloa‘a has provided numerous specimens for this revision, most often from difficult to access natural areas, and from months of the year with very few other records. Thus it is a pleasure to honor her contributions to Mecyclothorax diversity by naming this species in her honor.

Distribution and habitat

The type specimen was collected at 1950 m elevation in a pitfall trap near Paliku Cabin. The site lies in the mesic eastern end of Haleakalā Crater, and it receives windward moisture wafting over the highest elevations of Kīpahulu Valley to the east (Fig. 67).

Figure 67.

Recorded geographic distributions of M. ovipennis group species.

Mecyclothorax apicalis (Sharp)

Figs 61F–H, 62C, 63C, 65C, 67

Thriscothorax apicalis Sharp 1903: 264; Britton 1948b: 150.

Diagnosis

This species and M. parapicalis share: 1, evident microsculpture, isodiametric to transverse, on the vertex and pronotal disc; 2, divergent pronotal lateral margins anterad obtuse, glabrous hind angles; 3, shallow, impunctate discal elytral intervals that are of similar color to lateral elytral intervals 7–9. The pronotum is more basally constricted in individuals of this species—MPW/BPW = 1.46–1.54—and more transverse—MPW/PL = 1.26–1.33—than in beetles comprising M. parapicalis (Fig. 65C–D). The elytra are also narrower basally, with the lateral margins little extended laterally behind the tightly rounded humeri (Fig. 65C). The male aedeagal median lobe is distinctively different from that of M. parapicalis, with the apex sinuously recurved with an expanded, spoonlike tip (Figs 61F, G). Individuals of this species vary in the degree of punctation in the discal elytral striae. The striae vary from smooth, impunctate, to more irregular due to the presence of elongate punctulae (Fig. 65C). This variation is taken into account in the dichotomous key above. Setal formula 2 1 2 0. Standardized body length 4.0–4.2 mm.

Identification

(n = 5). Characters of the pronotum can assist identification, with the median base depressed relative to the disc, the surface strigose laterally and sparsely punctate medially. The anterior transverse impression is shallow, broad, with sparse longitudinal wrinkles behind. The laterobasal depression is slightly convex medially, and depressed laterally and basally along the beaded pronotal margin. On the elytra, the narrower elytral base is associated with a very narrow marginal depression at the humeri, with the narrow marginal depression concolorous with the elytral intervals. Overall, the body coloration is dark: 1, vertex rufobrunneous with piceous cast; 2, pronotal and elytral disc rufopiceous; 3, elytral apex narrowly flavous along margins (Fig. 65C). The frons and vertex bear well-developed isodiametric sculpticells in transverse rows. The pronotal disc is covered with isodiametric to slightly transverse sculpticells in transverse rows, the isodiametric microsculpture on the median base more upraised, again arranged in transverse rows.

Male genitalia (n = 4). Aedeagal median lobe slender, distance between parameral articulation and tip 5× depth at midlength (Fig. 61F); apex sinuously extended beyond apex of ostial opening, dorsoventrally expanded near bluntly rounded tip; median lobe straight overall in ventral view, the apex offset to right relative to the shaft, tip blunt (Fig. 61H); internal sac with ventral ostial microtrichial patch, flagellar plate very small, length 0.24× parameral articulation-tip distance (Fig. 61G).

Female reproductive tract (n = 1). Bursa copulatrix columnar, elongate, length 0.91 mm, breadth 0.39 mm (Fig. 62C); bursal walls moderately thick, wrinkled; gonocoxite 1 with 1–2 apical fringe setae, and only 2–4 very small setae on medial half of gonocoxite (Fig. 63C); gonocoxite 2 broadly triangular with laterally curved apex, base with broad lateral extension, 2 lateral ensiform setae with apical seta broader and longer (a minute third, basal ensiform seta present unilaterally), apical nematiform setae on medial surface at 0.68× gonocoxite length.

Lectotype

Female (BMNH) hereby designated, labeled: Thriscothorax apicalis Type D.S. Haleakala Perkins 254 // Type // Hawaiian Is. Perkins 1904-336. // LECTOTYPE Thriscothorax apicalis Sharp J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat

M. apicalis is a species of open Deschampsia nubigena (hairgrass) grasslands, both along the upper northwest slope and in Haleakalā Crater (Fig. 67). Beetles have been found in the moist soil of bunchgrass tufts, and by pitfall trapping. Although the species has been collected recently across its range, the Argentine Ant, Linepitheme humile (Mayr), represents a threat to persistence of its populations when the two are sympatric, as they are on the northwest slope. Ant presence has been shown to have a statistically significant negative effect on beetle abundance in that situation (Liebherr and Krushelnycky 2007).

Mecyclothorax parapicalis sp. n.

Figs 61I, 65D, 67

Diagnosis

Like M. apicalis, but the body is broader at the elytral base, and the elytral lateral margins are slightly extended laterally behind the humeri, the humeral angle defined by a slight hitch at the base of the moderately broad lateral marginal depression (Fig. 65D). The microsculpture on the forebody is more transverse, with: 1, a shallow transverse mesh, sculpticell breadth 2–3× length on the vertex; 2, transverse mesh, sculpticell breadth 3× length, to transverse lines on the pronotal disc; and 3, evident isodiametric and transverse sculpticells over the pronotal median base. The male aedeagal median lobe exhibits a rhomboidal apex, with the apical and ventral margins meeting at an acute angle (Fig. 61I).

Setal formula 2 1 2 0. Standardized body length—3.8–3.9 mm—is slightly smaller than that of M. apicalis; length 4.0–4.2 for that species.

Description

(n = 3). Head capsule with frontal grooves broad near clypeus, a broad lateral carina to anterior supraorbital seta; dorsal surface of neck flat to slightly concave; eyes moderately convex but covering much of ocular lobe, ocular ratio = 1.41–1.46, ocular lobe ratio = 0.82–0.84; labral anterior margin medially emarginate 1/6 of length; antennae submoniliform, antennomeres 2–3 with sparse pelage of short setae; mentum tooth with sides acute, apex tightly rounded. Pronotum transverse, MPW/PL = 1.28–1.36, broad basally, MPW/BPW = 1.41–1.45; hind angle slightly obtuse, margin rounded behind or not, lateral margin subparallel or slightly divergent immediately anterad angle; median base slightly depressed relative to disc, smoother medially, laterally punctate, longitudinal wrinkles lining juncture with disc; basal margin broadly, slightly convex between laterobasal depressions; median longitudinal impression very shallow, finely incised; anterior transverse impression deep, finely incised, shallower at midline; anterior callosity slightly convex, smooth, glossy; front angles slightly produced, tightly rounded; pronotal apical width slightly narrower than basal width, APW/BPW = 0.93–0.97; lateral marginal depression narrow throughout, edge beaded except where slightly broader at front angles; laterobasal depression broadly convex between median base and hind angle. Proepisternum with 5 minute punctures along hind marginal groove; prosternal process with narrow median impression, margins beaded between coxae. Elytra subquadrate, disc flat, sides distinctly sloped; basal groove distinctly recurved inside humeral angle; elytra broadest behind midlength and humeri extended laterally in concert with broad pronotal base, MEW/HuW = 1.95–2.0; parascutellar seta present; parascutellar striole with 5 punctures, shallow but continuous between punctures; sutural interval flat in basal half, progressively elevated along suture to apex; sutural and 2nd striae of subequal depth from base to apex; discal striae 1–4 smooth, shallow, striae 5–6 shallower, traceable, stria 7 absent; discal elytral intervals 2–6 only slightly convex to nearly flat on lateral intervals; 8th interval slightly more convex than apical fused portion of striae 5 + 7; 2 dorsal elytral setae at 0.32× and 0.67× elytral length, setal impressions small, spanning ½ width of interval 3; apical and subapical setae absent; lateral elytral setae arranged in anterior series of 7 setae and posterior series of 6 setae; elytral marginal depression of moderate breadth at humerus, narrowed laterad posterior setal series, margin upturned except beaded at subapical sinuation; subapical sinuation shallow, more abruptly incurved anteriorly. Mesepisternum with ~6 punctures in 1–2 rows; metepisternal width to length ratio = 0.75; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1–5, and lateral depressions on ventrites 3–6; suture between ventrites 2 and 3 reduced laterally, effaced; apical male ventrite with 2 marginal setae. Legs-metatarsomere 1/metatibial length ratio = 0.19; metatarsomere 4 length along outer lobe 1.33× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci narrow, shallow, median area broad. Microsculpture of elytral disc consisting of distinct isodiametric and transverse sculpticells arranged in a mesh, elytral apex with transverse mesh, sculpticell breadth 2× length; metasternum with distinct transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous; antennomeres 1–3 rufoflavous, 4–11 darker, brunneous; pronotal disc rufobrunneous with piceous cast, lateral margins, base, and apex narrowly rufobrunneous; proepipleuron rufoflavous, proepisternum rufobrunneous; elytral disc rufobrunneous with slightly metallic reflection, sutural interval concolorous basally, rufoflavous apically; intervals 7–8 inside humeral angle plus lateral marginal depression rufoflavous; elytral apex contrastedly flavous from apical terminus of interval 4; elytral epipleuron dorsally rufoflavous, ventrally rufobrunneous, metepisternum rufobrunneous; abdomen with ventrites 1–6 medially rufopiceous, ventrites 3–6 laterally rufoflavous, abdominal apical ventrite with apical 1/6 paler, flavous; metafemur flavous; metatibia flavous with brunneous cast.

Male genitalia (n = 1). Aedeagal median lobe robust, distance between parameral articulation and tip 3.8× depth at midlength (Fig. 61I); apex trapezoidal, with flat apical face and angled ventral margin meeting at tightly rounded tip; internal sac with diffusely developed dorsal ostial microtrichial patch, flagellar plate short, length 0.3× parameral articulation-tip distance.

Holotype

Male (BPBM) labeled: HAWAII: E. Maui I: / Haleakala Nat. Park / Haleakala Crater / 2134 m 1.VIII.1973 / Deschampsia nubigena / W.C. Gagné Coll. / BISHOP Museum // Mecyclothorax / parapicalis / ♂ photo / det. J.K. Liebherr 2014 // HOLOTYPE / Mecyclothorax / parapicalus / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes

Same data as holotype (BPBM, 1; CUIC, 1)

Etymology

The similarity of this species to M. apicalis makes the species epithet parapicalis appropriate; the adjectival epithet meaning like apicalis

Distribution and habitat

The distribution of M. parapicalis is completing subsumed by that of the very similar appearing species M. apicalis (Fig. 67). This species is known only from three specimens collected by Dr. Wayne Gagné in association with Deschampsia nubigena (hairgrass) in the vicinity of Holua Cabin. The specimens were collected during August, whereas all specimens of the closely related M. apicalis have been collected in March, April, June, July, and October.

Mecyclothorax mauiae sp. n.

Figs 62D–E, 63D, 68A, 69, 71

Diagnosis

Among the assemblage of M. ovipennis group species with punctate discal elytral striae and concolorous elytral intervals, this and the next species, M. subternus, stand out due to their broadly ellipsoid to obovoid elytra (Fig. 68A–B). The pronotum characterizing these species is also very constricted basally—MPW/BPW = 1.58–1.72 for this species—with a minutely punctate, glossy median base. Mecyclothorax mauiae can be diagnosed from M. subternus by the better developed microsculpture: 1, vertex with evident transverse mesh, sculpticell breadth 2× length; and 2, pronotal and elytral discs and elytral apex with transverse mesh, sculpticell breadth 2–3× length. The eyes also tend to be less convex and slightly smaller than in M. subternus, with ocular ratio = 1.43–1.50, and ocular lobe ratio = 0.75–0.79 in this species. The final arbiter for any identification involving a male specimen is the apex of the aedeagal median lobe, with the apex always rounded in male of this species (Fig. 69) versus acuminate in M. subternus (Fig. 70A–D). The degree of strial development varies among individuals of this species, potentially allowing specimens of this species to be confused with those of M. nanunctus of the M. palustris group. That group is characterized by a less depressed apex on elytral stria 2; a character exhibiting some infraspecific variation. Specimens of M. mauiae always exhibit broader pronotal lateral marginal depressions, and more ellipsoid elytra than observed in individuals of M. nanunctus. As with M. subternus, examination of male genitalia will finalize the diagnosis, as the male aedeagal median lobe of M. nanunctus is much more elongate and gracile, with the apex terminated in narrowly projected tip (Fig. 153D–J). Setal formula 2 1 2 0. Standardized body length 3.4–4.5 mm.

Figure 68.

Mecyclothorax ovipennis group species, habitus view. A M. mauiae (Ke‘anae, 1325 m) B M. subternus (Kuhiwa E rim, 880 m) C–D M. flaviventris (Kīpahulu, 1500 m) C Dorsal view D Ventral view.

Description

(n = 5). Head capsule with frontal grooves broad near clypeus, lateral carina to supraorbital seta; dorsal surface of neck flat to slightly concave; labral anterior margin very shallowly emarginate medially; antennae filiform, antennomeres 2–3 with sparse pelage of short setae; mentum tooth with sides acute, apex rounded. Pronotum cordate, moderately transverse, MPW/PL = 1.23–1.27; hind angle right to slightly acute, lateral margin convergent just before angle; median base almost coplanar to slightly depressed relative to disc, ~12 sparsely distributed punctures each side; basal margin convexly expanded between laterobasal depressions; median longitudinal impression shallow, finely incised, crossed by fine transverse wrinkles; anterior transverse impression narrow, shallowly incised laterally, obsolete medially; anterior callosity slightly convex, smooth to slightly irregular due to fine wrinkles, surface glossy; front angles slightly projected, rounded; pronotal apical width greater than basal width, APW/BPW = 1.03–1.11; lateral marginal depression moderately narrow, edge beaded anterad lateral seta, broader at front angle, edge little upturned in basal half; laterobasal depression narrow and deep, continuous with lateral depression. Proepisternum with 5 minute punctures along hind marginal groove; prosternal process with narrow median impression, lateral margins broadly beaded between coxae. Elytra broadly obovoid, disc narrowly flat medially, sides steeply sloped; basal grooves briefly recurved to proximate humeral angles, the tightly rounded to subangulate angles defined by hitch at the base of the lateral marginal depression, MEW/HuW = 2.28–2.51; parascutellar seta present; parascutellar striole with 4 isolated punctures, striole may be discontinuous between adjacent punctures; sutural interval slightly more convex than lateral intervals, sutural juncture upraised; sutural stria shallow between deep, round punctures basally, smooth, moderately deep apically, 2nd stria shallower but also with rounded punctures on disc, shallower and broader apically, the two striae of subequal depth at elytral apex; discal striae 3–4 very shallow, punctate on disc, stria 5 very shallow, traceable, striae 6–7 obsolete, associated inner intervals slightly convex, lateral intervals flat; 8th interval convex, though striae are obsolete in that area of elytra; 2 dorsal elytral setae at 0.31× and 0.56–0.58× elytral length, setal impressions shallow, spanning ½ to 2/3 width of interval 3; apical and subapical setae absent; lateral elytral setae arranged in anterior series of 7 setae and posterior series of 6 setae; elytral marginal depression slightly broader at humerus, narrowed laterally and posteriorly to beadlike at subapical sinuation; subapical sinuation shallow, concavity symmetrical. Mesepisternum with ~8 punctures in 1–2 rows; metepisternal width to length ratio = 0.70; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1–5, lateral depressions on ventrites 3–6; suture between ventrites 2 and 3 complete; apical male ventrite with 2 marginal setae; apical female ventrite with 4 equally spaced marginal setae and median trapezoid of 4, subequal, short setae. Legs-metatarsomere 1/metatibial length ratio = 0.18; metatarsomere 4 length along outer lobe 1.4× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci narrow, shallow, median area broad. Microsculpture of pronotal median base obsolete medially, the surface glossy, a transverse mesh present laterally between punctures; metasternum with shallow transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous; antennomere 1 flavous, antennomeres 2–3 brunneous, 4–11 with piceous cast; pronotal disc rufobrunneous, lateral margins narrowly, and base and apex rufous; proepipleuron rufoflavous, proepisternum rufobrunneous; elytral disc rufobrunneous basally, apical half the same with piceous cast, sutural interval rufous throughout, intervals 8–9 rufoflavous, paler apically; elytral epipleuron dorsally rufoflavous, ventrally darker, metepisternum rufobrunneous; abdomen with ventrites 1–3 rufobrunneous, ventrites 4–5 darker, rufopiceous, apical ventrite 6 rufoflavous mediobasally, apical half flavous; metafemur flavous; metatibia flavous with brunneous cast.

Male genitalia (n = 50). Aedeagal median lobe variably robust, distance between parameral articulation and tip 2.2–3.3× depth at midlength (Fig. 69E, M), but apex always little extended beyond ostial opening, with tip broadly rounded (Fig. 69); median lobe symmetrical in ventral view, broadest at midlength of lobe shaft, evenly narrowed to blunt tip which lies on right side of apex (Fig. 69B); internal sac broad, of variable length (Fig. 69H–J), sac length from ostium to base of flagellar plate 0.77–1.1× parameral articulation-tip distance, surface unornamented except denser microspicules may occur on ventral surface (Fig. 69J); flagellar plate very large, length 0.60–0.67× parameral articulation-tip distance.

Figure 69.

Male aedeagus, M. mauiae (for abbreviations see Table 2, p. 23). A–B Right and ventral view (Waikamoi, 1305 m) D–G Right view D (Waikamoi, 1160 m). E (Ke‘anae, 1325 m) F (Kopili‘ula, 1127 m). G (Kuhiwa, 1590 m) H–J Right view, sac everted H (Kuhiwa, 1580 m) I (Helele‘ike‘oha, 1615 m) J (Kīpahulu, 910 m) K–P Right view. K (Kīpahulu, 1500 m) L (Kīpahulu W rim, 1850 m) M (Pu‘u Ahulili, 1600 m) N (Ka‘āpahu, 1250 m) O (Midcamp Bog, 1665 m) P (Kuhiwa E rim, 880 m).

Female reproductive tract (n = 2). Bursa copulatrix columnar, elongate, length 1.08–1.16 mm, breadth 0.33–0.36 mm, an apical lobe offset from basal portion by curved constriction, apical lobe 0.49 mm long (Fig. 62D–E); bursal walls translucent with thick wrinkles; gonocoxite 1 with 3–4 apical fringe setae, the outermost setae of series smallest, and 5–8 smaller setae on medial surface (Fig. 63D); gonocoxite 2 falcate with tightly rounded tip, base with lateral panhandle extension with 90° bend at terminus, 2 lateral ensiform setae with apical seta longer and broader, apical nematiform setae on medial surface at 0.68× gonocoxite length.

Holotype

Male (CUIC) labeled: HI: Maui Haleakala NW / slope Waikamoi Flume / Waikamoi to Haipuaena / Gulches 11-IV-1991 / el. 1300 m J. Liebherr // under boards in / wet ohia rain / forest // HOLOTYPE / Mecyclothorax / mauiae / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes

817 specimens (see Appendix).

Etymology

This species’ similarity to M. molokaiae of Moloka‘i, suggests use of mauiae as the species epithet, the first declension genitive singular form to mean Maui’s Mecyclothorax.

Distribution and habitat

M. mauiae is broadly distributed across the windward face of Haleakalā, including Kīpahulu Valley, Kaumakani Peak and the Manawainui Planeze (Fig. 71). Collection localities range 880–1830 m elevation. This species is found in association with a variety of plant substrates, with ‘ōhi‘a and Cibotium (hāpu‘u) tree ferns most commonly associated with collections. Beetles have also been collected infrequently on koa trunks, and very commonly in sift samples of ‘ōhi‘a litter. Whereas the predominantly ground-dwelling species of the M. robustus and M. sobrinus species groups were trapped extensively in yellow-pan traps in the Waikamoi area (see above), only six specimens of M. mauiae were so trapped at one wet forest site (Kula Pipeline Road, 1183–1280 m elevation, vi-viii-2006, L. LeBlanc, UHIM).

Mecyclothorax subternus sp. n.

Figs 62F, 63E, 68B, 70A–D, 71

Diagnosis

Individuals of this species (Fig. 68B) are nearly identical externally to those of M. mauiae (Fig. 68A), though the eyes tend to be larger and more convex; ocular ratio = 1.48–1.54, ocular lobe ratio = 0.79–0.82, and the dorsal surface is less sculptured; 1, vertex, pronotal disc and median base, and elytral disc glossy, microsculpture obsolete; 2, elytral apex with shallow to obsolete transverse mesh, the surface glossy; 3, metasternum with shallow transverse-mesh microsculpture. The male aedeagal median lobe certifies the identification, as the apex terminates in a pointed tip (Fig. 70A–C) instead of the broadly rounded apex of M. mauiae (Fig. 69). Setal formula 2 1 2 0. Standardized body length 3.4–4.2 mm.

Figure 70.

Male aedeagus, M. ovipennis group species (for abbreviations see Table 2, p. 23). A–D M. subternus (Kuhiwa E rim, 880 m). A Right view B–C Right and left views, sac everted D Ventral view E–I M. flaviventris E Right view (Kīpahulu, 1845 m) F Ventral view (Kīpahulu, 1845 m) G Right view, sac everted (Kīpahulu, 1845 m) H Right view (Kīpahulu, 1500 m) I Right view (Paliku, 1950m) J–M M. laetus J–K Right and ventral views (Kīpahulu, 1900 m) L Right view (Kīpahulu, 1960 m) M Right view, sac everted (NW upper slope, 2072 m).

Description

(n = 5). The description of M. mauiae also serves for this species with the following substitutions. Pronotum slightly broader basally and more transverse than that of M. mauiae; MPW/BPW = 1.57–1.65, MPW/PL = 1.23–1.32. Pronotal lateral margin narrow, beaded, not wider at front angles. Discal elytral striae shallow between deep, rounded and nearly isolated punctures; discal elytral interval 2 slightly convex, intervals 3–4 nearly flat. Mesepisternum smooth, with 3–4 punctures arrayed in 1 row. Coloration pale (though single topotypic type series may include exclusively somewhat teneral individuals); vertex rufous; antennomere 1 flavous, antennomeres 2–3 rufoflavous, 4–11 brunneous; pronotal disc and margins pale rufous; elytral disc basally rufous, apically rufobrunneous, sutural interval basally rufoflavous, apically flavous; abdominal ventrites 1–5 mediobasally rufous, laterally and apically rufobrunneous; metafemur flavous with medial brunneous cloud.

Male genitalia (n = 2). Aedeagal median lobe robust, distance between parameral articulation and tip 2.5× depth at midlength (Fig. 70A–C); apex little extended beyond ostial opening, tip acutely pointed; median lobe symmetrical in ventral view, right margin broadly concave, left margin incurved to blunt tip which is on right side of apex (Fig. 70D); internal sac very broad basally, with oblong ventral ostial microtrichial patch on right side (Fig. 70B); flagellar plate very large, length 0.67× parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix a broad sac, length 1.23 mm, maximum breadth in apical half 0.65 mm, breadth at vagina 0.34 mm (Fig. 62F); bursal walls translucent with thick wrinkles; gonocoxite 1 with 3 apical fringe setae, middle seta of series largest, 8 smaller setae along medial margin (Fig. 63E); gonocoxite 2 falcate with acuminate tip, base with sinuous lateral extension, 2 lateral ensiform setae with apical seta broader and longer, apical nematiform setae on medial surface at 0.72× gonocoxite length.

Holotype

Male (NMNH) labeled: HI:Maui Haleakala Hana- / wi NAR Kuhiwa Vy. E rim / 9-VI-1999 lot 07 880 m el. / N20°46'25", W156°06'04" / D.A. Polhemus pyr. fog / Cibotium // Mecyclothorax / subternus / ♂ #40 / det. J.K. Liebherr 2014 // HOLOTYPE / Mecyclothorax / subternus / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes

Same data as holotype (BPBM, 2; CUIC, 3; NMNH, 5).

Etymology

The adjectival species epithet subternus, meaning that which is underneath (Jaeger 1955), signifies the geographical range of this species being at the lower elevational bounds of its closely related, and much more broadly distributed relative, M. mauiae (Fig. 71).

Figure 71.

Recorded geographic distributions of M. ovipennis group species.

Distribution and habitat

M. subternus is known only from a single locality along the lower elevational limit of the range of its much more extensively distributed cryptic sibling species, M. mauiae (Fig. 71). All 10 specimens of this species came from a single day of collecting on mossy ‘ōhi‘a trunks and logs. The type locality in Kuhiwa Valley is extremely wet both due to precipitation but also due to the extensive rainwater runoff from the upper elevations of Kuhiwa Valley. Yearly rainfall at 871 m elevation in Kuhiwa Valley averaged 9.75 m from 1934–1941 (Stearns and McDonald 1942); the highest average total for any station in East Maui during those years.

Mecyclothorax flaviventris sp. n.

Figs 62G, 63F, 68C–D, 70E–I, 72

Diagnosis

This species is the most gracile-bodied M. ovipennis group species with cordate pronotum, narrowed elytral humeri, and punctate discal elytral intervals (Fig. 68C). In body conformation it is most similar to M. ovipennis (Fig. 65A), and both species share the setal formula 2 2 2 1[ae]. However individuals of this species lack the parascutellar seta. Also, this species is uniquely characterized among species in the group by the apically flavous abdomen, with the flavous ventrites 4–6 contrasted to the rufobrunneous basal ventrites (Fig. 68D). Standardized body length 3.7–4.1 mm.

Description

(n = 5). Head capsule with frontal grooves broad near clypeus, lateral carina to supraorbital seta; dorsal surface of neck flat to slightly concave; eyes large and moderately convex, ocular ratio = 1.51–1.56, ocular lobe ratio = 0.82–0.88; labral anterior margin deeply angulate medially, emarginated 1/3 of length; antennae filiform; antennomeres 2–3 with only a few short setae along shafts; mentum tooth with sides acute, apex tightly rounded. Pronotum quadrisetose, distinctly constricted basally, MPW/BPW = 1.49–1.58, with lateral margins convergent before the right to slightly acute, projected hind angles; pronotum appearing narrow, but actually slightly transverse, MPW/PL = 1.13–1.21; median base broadly depressed relative to disc, rugose medially, longitudinally strigose laterally; basal margin very slightly convex between laterobasal depressions; median longitudinal impression evident, finely incised, continued onto median base; anterior transverse impression broad, surface with granulate microsculpture and deep, dense longitudinal wrinkles; anterior callosity depressed, covered with longitudinal wrinkles from transverse impression; front angles not projected, tightly rounded; pronotal apical width greater than basal width, APW/BPW = 1.06–1.09; lateral marginal depression moderately narrow, edge upturned, slightly broader inside front angle; laterobasal depression slightly transversely wrinkled, continuous with lateral depression. Proepisternum with 4–5 minute punctures along hind marginal groove; prosternal process with narrow median impression, lateral margins broadly beaded between coxae. Elytra distinctly ovoid with maximal width behind midlength, disc narrowly flat medially, sides steeply sloped; basal groove gently recurved to subangulate humerus that is defined by hitch at base of lateral marginal depression, MEW/HuW = 2.10–2.18; parascutellar striole very shallow, smooth, difficult to trace; sutural interval slightly more convex than lateral intervals, but depressed at suture; sutural and 2nd striae of subequal depth from base to apex, striae 2–6 progressively shallower on disc, stria 7 discontinuous, obsolete, discal striae 1–4 with small punctures restricted to deepest parts of striae; 8th interval slightly more convex than apical fused portion of striae 5 + 7; 2 dorsal elytral setae at 0.30–0.31× and 0.61–0.66× elytral length, setal impressions shallow, spanning ½ width of interval 3; apical elytral seta present near medial apex of interval 3, subapical seta absent; lateral elytral setae arranged in anterior series of 7 setae and posterior series of 6 setae; elytral marginal depression moderately narrow, edge upraised until beaded at subapical sinuation; subapical sinuation shallow, more abruptly incurved anteriorly. Mesepisternum with ~8 punctures in 1–2 rows; metepisternal width to length ratio = 0.71; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1–5, lateral depressions on ventrites 3–6 (Fig. 68D); suture between ventrites 2 and 3 reduced laterally, effaced; apical male ventrite with 2 marginal setae, apical female ventrite with 4 equally spaced setae plus median trapezoid of 4 subequal, short setae. Legs-metatarsomere 1/metatibial length ratio = 0.21; metatarsomere 4 length along outer lobe 1.33× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci narrow, shallow, median area broad. Microsculpture of vertex and pronotal disc a transverse mesh, sculpticell breadth 2–3× length; pronotal median base with granulate isodiametric and transverse mesh, sculpticell breadth 2× length; elytral disc with shallow isodiametric and transverse mesh, sculpticell breadth 2× length, in transverse rows; elytral apex with shallow isodiametric sculpticells in transverse rows; metasternum with upraised transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous with piceous cast; antennomeres 1–3 flavous, 4–11 darker, more brunneous; pronotal disc rufopiceous, lateral margins, base, and apex narrowly rufoflavous; proepipleuron rufoflavous, proepisternum rufobrunneous; elytral disc dark rufobrunneous, sutural interval narrowly rufobrunneous basally, rufoflavous apically; elytral marginal depression and 9th interval rufoflavous, elytral apex narrowly flavous; elytral epipleuron dorsally flavous, ventrally rufoflavous, metepisternum rufopiceous; abdomen with ventrites 1–2 rufobrunneous, ventrite 3 medially rufobrunneous, laterally and apically flavous, ventrites 3–6 flavous; metafemur flavous; metatibia flavous with a brunneous cast.

Male genitalia (n = 5). Aedeagal median lobe variably gracile, distance between parameral articulation and tip 3.7–4.2× depth at midlength (Fig. 70E, H, I); apex extended twice its depth beyond apex of ostial opening, tip slightly downturned, rounded; median lobe curved rightward toward apex in ventral view (Fig. 70F), right margin concave, left margin incurved to blunt tip; internal sac elongate, length from ostial margin to base of flagellar plate 0.79× parameral articulation-tip distance, sac surface unornamented but with microspicules more developed over entire ventral surface (Fig. 70G); flagellar plate moderately short, length 0.36× parameral articulation-tip distance. The male from Kīpahulu Valley, 1500 m elevation (Fig. 70H) exhibits a broader apex, though the internal sac in its uneverted condition looks identical to the configuration of the Kīpahulu Valley, 1845 m elevation male (Fig. 70E). All of these specimens exhibit the flavous abdominal ventrites that represent an autapomorphy for the species, and if the lower elevation Kīpahulu Valley population is determined to be distinct, the additionally recognized species will be the sister to M. flaviventris. A present, with only a single specimen from the lower Kīpahulu Valley locality, such recognition is deemed premature, and the aedeagal conformations are assumed to represent infraspecific variability.

Female reproductive tract (n = 1). Bursa copulatrix columnar with rounded, slightly expanded apex, length 0.68 mm, breadth 0.29 mm (Fig. 62G); bursal walls translucent with thin wrinkles; gonocoxite 1 with 0–1 apical fringe setae and 7–8 smaller setae on medial surface (Fig. 63F); gonocoxite 2 falcate with tightly rounded tip, base with long, thin lateral extension with 90° bend at terminus, 2 lateral ensiform setae, the apical seta longer and broader, apical nematiform setae on medial surface at 0.69× gonocoxite length.

Holotype

Male (CUIC) dissected and labeled: HI:Maui Haleakala N.P. / Kipahulu Vy. 1500 m el. / 9-V-1991 sifting / leaf litter by day // S. Jessel / A.C. Medeiros, / Jr. collectors // Mecyclothorax / flaviventris / ♂ #4 / det. J.K. Liebherr 2014 // HOLOTYPE / Mecyclothorax / flaviventris / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes

35 specimens (see Appendix).

Etymology

The Latin genitive singular flaviventris signifies the flavous abdominal ventrites 4–6 contrasted to the piceous abdominal base.

Distribution and habitat

M. flaviventris has a distribution that is centered on the upper elevations of Kīpahulu Valley, extended northward into the Hāna Bogs, westward to the eastern mesic margin of Haleakalā Crater at Paliku, and southward to Kīpahulu’s west rim near Kuiki (Fig. 72). Collecting localities span 1500–2100 m elevation. The beetles have almost always been collected in association with mossy ‘ōhi‘a trunks and logs. Several beetles have been encountered while beating vegetation, and one was captured in a pitfall trap at Paliku.

Figure 72.

Recorded geographic distribution of M. flaviventris.

Mecyclothorax laetus (Blackburn)

Figs 62H, 70J–M, 73A, 74A, 75

Cyclothorax laetus Blackburn 1881: 228; Blackburn and Sharp 1885: 216.

Thriscothorax laetus, Sharp 1903: 262.

Mecyclothorax laetus Sharp 1903: 247; Britton 1948b: 149 (synonymy, subsequent homonymy); Liebherr 2005b: 111.

Thriscothorax subconstrictus, Swezey 1954: 53, 60 (misidentification, Cibotium and rotten wood associate).

Diagnosis

The rufobrunneous dorsal body color, narrow, cordate pronotum, and well-developed dorsal microsculpture–isodiametric on the elytra–will allow individuals of this species to be identified in the field using a hand lens (Fig. 73A). More microscopic characters amply diagnosis this species, including: 1, elytral parascutellar seta absent; 2, dorsal elytral setae absent, though a single seta may be present in rare instances; 3, vertex with shallow transverse mesh, sculpticell breadth 2× length, and pronotal disc with transverse mesh, sculpticell breadth 2–3× length. Setal conformation is highly variable among individuals of this species, with the basal pronotal setae present or absent, and either both apical and subapical elytral setae, or just the subapical seta present. Setal formula 2 1-2 0(1) 1-2[sae]. Standardized body length 3.9–4.6 mm.

Figure 73.

Mecyclothorax ovipennis group species, dorsal habitus view. A M. laetus (Kīpahulu, 1900 m) B M. cordaticollis (Olinda-Ukulele Camp Pipeline, 1210–1524 m) C M. cordaticollaris (Kaupō Gap, 1170 m) D M. subconstrictus (summit, 2895–3050 m).

Identification

(n = 5). The eyes are slightly to moderately convex, ocular ratio = 1.41–1.46, covering more than ¾ of the little protruded ocular lobe; ocular lobe ratio = 0.77–0.82. The antennae are submoniliform, with antennomeres 5–11 expanded apically. The pronotal lateral margin is distinctly concave anterad the right to acute hind angle, the basal sinuation extended for 1/7 the length of the pronotum. The pronotum is narrow to slightly transverse, MPW/PL = 1.13–1.23, with a somewhat variable basal constriction; MPW/BPW = 1.39–1.51. The narrow subquadrate elytra are flat medially, with discal striae 1–5 shallow and minutely punctate, stria 6 obsolete but traceable, and stria 7 absent. All intervals save the slightly convex sutural interval are only slightly convex to flat. When a single dorsal elytral seta is present, it is in the basal position; 0.24× elytral length.

Male genitalia (n = 3). Aedeagal median lobe moderately robust, distance between parameral articulation and tip 3.4× depth at midlength (Fig. 70J, L); apex sinuously extended beyond ostial opening, apex dorsoventrally expanded, either more dorsally than ventrally (Fig. 70J), or broadly both ventrally and dorsally (Fig. 70L–M); median lobe straight in ventral view, but thin elongate apex offset toward right side of shaft, with right margin concave basad apex, and left margin distinctly incurved to meet apex, tip appearing tightly rounded from ventral aspect (Fig. 70K); internal sac broad, with broad, diffuse ventral ostial microtrichial field, otherwise covered only with fine microspicules (Fig. 70M); flagellar plate moderately large, length 0.49× parameral articulation-tip distance. That the variably expanded apex represents infraspecific variation is supported by both narrower and broader apices (Fig. 70J, L) being found in males from Kīpahulu Valley, West Camp, 1900–1960 m elevation.

Female reproductive tract (n = 1). Bursa copulatrix columnar, apical lobe set off by constriction, reminiscent of a ginger jar with small lid; overall length 0.83 mm, apical lobe 0.25 mm long × 0.45 mm broad, shaft breadth 0.44 mm, and basal constriction 0.26 mm broad at vagina (Fig. 62H); bursal walls translucent, thinly wrinkled basally, apical lobe more wrinkled and less stained; gonocoxite 1 with 5 apical fringe setae, 6 smaller setae—1 at medioapical angle—along medial surface (Fig. 74A); gonocoxite 2 falcate with pointed apex, base broadly extended laterally, 2 short lateral ensiform setae, apical nematiform setae on medial surface at 0.77× gonocoxite length.

Figure 74.

Left female gonocoxa, M. ovipennis group species, ventral view. A M. laetus (Ukulele Camp Pipeline, 1495–1525 m) B M. cordaticollis (nr. Ukulele Camp, 1525 m) C M. cordaticollaris (Kaupō Gap, 1495 m) D M. subconstrictus (summit, 2895–3050 m) E M. pusillus (summit, 2895–3050 m) F M. rusticus (summit, 2895–3050 m).

Lectotypes

For Cyclothorax laetus Blackburn, male designated by Liebherr (2005b: 113). For Mecyclothorax laetus Sharp, female designated by Liebherr (2005b: 114). Type locality for the former is Haleakala, Maui, ~4000 ft.; i.e. the Waikamoi area; type locality for the latter is Haleakala, Maui, 5000 ft. (R.C.L.P. lot 661; Anonymous N D), i.e. near Ukulele Camp.

Distribution and habitat

M. laetus exhibits a very broad geographic distribution (Fig. 75), though the species is extensively absent from the Ke‘anae Valley and Hanawī face of Haleakalā. This absence is made the more peculiar by the very broad ecological preference suggested for this species by the disparate arrays of collecting situations. Consistent with occupation of the forests west of Waikamoi Gulch, this species has been found on mossy ‘ōhi‘a trunks, on koa trunks, and associated with Cibotium (hāpu‘u) ferns. But it has also been collected by sifting soil around Deschampsia (hairgrass) clumps in open shrubland. More exotically, it has been collected in large numbers under the loose bark of downed alien Pinus ponderosa in a disturbed grassland on the northwest slope. And in the alien afforested areas of Polipoli Springs it has been found by grubbing in deep pine needle litter. The presence of free moisture is a constant in all of these situations, though the degree of solar insolation varies dramatically.

Figure 75.

Recorded geographic distribution of M. laetus.

Mecyclothorax cordaticollis (Blackburn)

Figs 62I, 73B, 74B, 76A–B, 77

Cyclothorax cordaticollis Blackburn 1878b: 156; Blackburn and Sharp 1885: 215.

Thriscothorax cordaticollis, Sharp 1903: 259.

Mecyclothorax cordaticollis, Britton 1948b: 148.

Thriscothorax modestus Sharp 1903: 259; Britton 1948b: 148 (synonymy).

Diagnosis

This species (Fig. 73B), M. cordaticollaris (Fig. 73C), and M. subconstrictus (Fig. 73D) are the only three M. ovipennis group species to exhibit the 2 1 1 0 setal formula (at least for some of the individuals of the latter species). Mecyclothorax cordaticollis and M. subconstrictus share shallow, minutely punctate discal elytral intervals and associated slightly convex intervals, plus a narrowly constricted pronotum; MPW/BPW = 1.55–1.61 in this species. The discal elytral striae are much more punctate in M. cordaticollaris, and the associated intervals are much more convex. Mecyclothorax cordaticollis and M. subconstrictus can be definitively diagnosed using dorsal microsculpture. The pronotal disc of M. cordaticollis bears transverse-mesh microsculpture, sculpticell breadth 2–3× length, and the elytral disc is covered with a transverse mesh, sculpticell breadth 2–4× length. For M. subconstrictus, the pronotal disc is glossy medially, and laterally covered with an obsolete transverse mesh, whereas the elytral disc bears a mixture of isodiametric and transverse sculpticells. Standardized body length 3.6–4.1 mm.

Identification

(n = 4). The eyes are moderately convex, ocular ratio = 1.42–1.49, but they cover much of the ocular lobe, ocular lobe ratio = 0.81–0.86. The pronotal lateral marginal depression is narrow, the edge upturned anterad lateral seta, slightly broader near front angle, and thin and beadlike along basal sinuation. The pronotal apical width is greater than the basal width; APW/BPW = 1.01–1.06. The elytra are subquadrate, with the tightly rounded humeral angles connected medially to only slightly recurved basal grooves. Though all the striae are shallow, they are all of similar depth on the elytral apex.

Male genitalia (n = 1). Aedeagal median lobe short, squat, distance between parameral articulation and tip 2.5× depth at midlength (Fig. 76A); apex extended beyond ostial opening equal to its depth, tip broadly rounded; median lobe curved rightward apically in ventral view (Fig. 76B), right margin slightly concave near tip, left margin broadly convex; internal sac with ventral ostial microtrichial patch indicated in uneverted specimen, shadow of flagellar plate also visible, the plate quite elongate, length 0.67× parameral articulation-tip distance.

Figure 76.

Male aedeagus, M. ovipennis group species. A–B M. cordaticollis, right and ventral views (Olinda-Ukulele Camp Pipeline, 1210–1524 m) C–D M. cordaticollaris, right and ventral views (Kaupō Gap, 1495 m) E–F M. subconstrictus, right and ventral views (summit, 2895–3050 m) G–H M. pusillus, right and ventral views (summit, 2895–3050 m) I–J M. rusticus, right and ventral views (summit, 2895–3050 m).

Female reproductive tract (n = 1). Bursa copulatrix columnar, length 0.84 mm, breadth 0.34–0.38 mm (Fig. 62I); bursal walls translucent, thinly wrinkled; gonocoxite 1 with 3 apical fringe setae, middle seta larger, 1 small seta at apicomedial angle, and 4–5 setae on medial surface (Fig. 74B); gonocoxite 2 broadly subtriangular, apex tightly rounded, base moderately extended laterally, 2 short lateral ensiform setae, apical nematiform setae on medial surface at 0.75× gonocoxite length.

Lectotypes

For Cyclothorax cordaticollis, female (BMMH) hereby designated, labeled: mounting platen with Blackburn Maui label (Zimmerman 1957: 210), cord (on reverse) // Type // Hawaiian Is. Rev. T. Blackburn 1888-30. // LECTOTYPE Cyclothorax cordaticollis Blackburn J.K. Liebherr 1998 (black-margined red label). For Thriscothorax modestus, male (BMNH) hereby designated, labeled: Thriscothorax modestus Type D.S. Haleakala 350 // Type // Hawaiian Is. Perkins 1904-336. // LECTOTYPE Thriscothorax modestus J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat

M. cordaticollis is known from only three definitive localities in the leeward forests west of Waikamoi Gulch (Fig. 77). Ukulele Camp (Site) is the most likely locality given Perkins’ (1894, 1896b) field notes. There no collecting records since Perkins collected two specimens in 1902.

Figure 77.

Recorded geographic distributions of M. ovipennis group species.

Mecyclothorax cordaticollaris sp. n.

Figs 62J, 73C, 74C, 76C–D, 77

Diagnosis

Like M. cordaticollis (Fig. 73B) or M. subconstrictus (Fig. 73D) in the setal formula—2 2 1 0—but with much deeper elytral striae, the discal striae 1–5 distinctly punctate with the punctures expanding strial breadth (Fig. 73C). The pronotal median base is minutely punctate, ~15 distinct punctures each side, with the punctures elongate at the juncture with the disc. The pronotal disc is glossy, with obsolete transverse-mesh microsculpture, sculpticell breadth 3× length, and the median base is glossy medially, and with an isodiametric mesh present laterally between the punctures. The elytra are relatively broader basally than in M. cordaticollis or M. subconstrictus, with the basal groove distinctly recurved to meet the angulate humerus, the angle defined by a hitch at the base of the lateral marginal depression. Standardized body length 3.9–4.4 mm.

Description

(n = 4). Head capsule with frontal grooves broad near clypeus, straight, lateral carina to anterior supraorbital seta; dorsal surface of neck flat to slightly concave; eyes moderately convex, ocular ratio = 1.48–1.50, ocular lobe ratio = 0.78–0.82; labral anterior margin very shallow emarginate medially; antennae filiform, antennomeres 2–3 with sparse pelage of short setae; mentum tooth with sides right, apex rounded. Pronotum transverse, MPW/PL = 1.24–1.27, constricted basally, MPW/BPW = 1.47–1.55; hind angle right, lateral margins subparallel to slightly convergent anterad projected angles; basal margin slightly, evenly convex between laterobasal depressions; median longitudinal impression shallow, finely incised; anterior transverse impression moderately deep, smooth, finely incised; anterior callosity slightly convex, smooth, glossy; front angles very slightly produced, broadly rounded; apical and basal pronotal widths subequal, APW/BPW = 0.95–1.0; lateral marginal depression narrow, edge upturned anterad seta, slightly broader at front angle, beadlike margin from midlength to basal sinuation; laterobasal depression smooth laterad median base, broadly raised in explanate lateral margin. Proepisternum with 5 minute punctures along hind margin; prosternal process with narrow median impression, lateral margins broadly beaded between coxae. Elytra broadly ovoid, disc moderately convex, sides more so; MEW/HuW = 2.11–2.16; parascutellar seta present; parascutellar striole with 4 punctures, continuous between punctures; sutural interval only slightly more convex than lateral intervals in basal half, more convex apically; sutural and 2nd striae of subequal depth from base to apex; elytral intervals 2–4 moderately convex, lateral intervals flatter; 8th interval slightly more convex than fused apical portion of striae 5 + 7; one dorsal elytral seta at 0.23–0.28× elytral length, setal impression small, spanning ½ width of interval 3; apical and subapical setae absent; lateral elytral setae arranged in anterior series of 7 setae and posterior series of 6 setae; elytral marginal depression narrow, margin upturned, beadlike near subapical sinuation; subapical sinuation shallow, more abruptly incurved anteriorly. Mesepisternum with ~10 punctures in 2–3 rows; metepisternal width to length ratio = 0.65; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1–5 and lateral depressions on ventrites 3–6; suture between ventrites 2 and 3 reduced laterally, effaced; apical male ventrite with 2 marginal setae, apical female ventrite with 4 equally spaced marginal setae plus median trapezoid of 4 subequal, short setae. Legs-metatarsomere 1/metatibial length ratio = 0.21; metatarsomere 4 length along outer lobe 1.25× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci shallow, narrow, median area broad. Microsculpture of vertex distinct, transversely stretched, sculpticell breadth 2–3× length; elytral disc with shallow transverse mesh, sculpticell breadth 3–4× length, apex with more developed transverse mesh of same dimensions; metasternum with shallow transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous; antennomeres 1–3 flavous, 4–11 darker, more brunneous; pronotal disc rufobrunneous with piceous cast, lateral margins, base, and apex rufoflavous; proepipleuron rufoflavous, proepisternum rufobrunneous with piceous cast; elytral disc rufobrunneous, sutural interval paler rufous basally, rufoflavous apically; elytral lateral marginal depression narrowly rufoflavous, apex contrastedly flavous from apical terminus of interval 4; elytral epipleuron rufoflavous, metepisternum rufopiceous; abdominal ventrites 1–2 rufopiceous, ventrites 3–5 medially rufopiceous, laterally paler, apical ventrite with apical half flavous; metafemur flavous; metatibia flavous with brunneous cast.

Male genitalia (n = 1). Aedeagal median lobe extremely slender, apically narrowed, needlelike, distance from parameral articulation to tip 5.9× depth at midlength (Fig. 76C); apex elongate, very narrow, angled slightly downward about half way along apical extension, with tip narrowly rounded; median lobe straight in ventral view, right and left margins approaching each other for 1/3 lobe length in this view, tip narrowly pointed (Fig. 76D); internal sac without apparent microtrichial fields in uneverted specimen, flagellar plate length estimated to be 0.35× parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix broad basally at vagina, with elongate, digitiform apical lobe, overall bursal length 0.74 mm, with apical lobe 0.51 mm long × 0.19 mm broad, and basal bulb at vagina 0.23 mm long × 0.41 mm broad (Fig. 62J); bursal walls smooth, only lightly wrinkled, the walls of apical lobe thinner, less stained than broad base with darker staining and thicker wrinkles; gonocoxite 1 with 4 apical fringe setae, medial surface lined with 7–10 smaller setae (Fig. 74C); gonocoxite 2 falcate with subacuminate apex, base broadly extended by short panhandle with curved terminus, 2 short lateral ensiform setae with apical seta longer and broader, apical nematiform setae on medial surface at 0.68× gonocoxite length.

Holotype

Male (CUIC) dissected and labeled: HI: Maui Haleakala N.P. / Kaupo Gap el. 1160 m / N20°40'43", W156°08'09" / 17-V-2001 lot 05 beating / ferns J.K. Liebherr // 1 // HOLOTYPE / Mecyclothorax / cordaticollaris / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes

HI: Maui, Kaupo Gap Tr., beating Pipturus, 1340 m el., 31-viii-1996 lot 01, Ewing (CUIC, 1), sifting Acacia koa/fern/moss litter, 1495 m el., 17–18-v-2001 lot 03, Liebherr (CUIC, 1), same data as holotype (CUIC, 1).

Etymology

This species’ great similarity to M. cordaticollis leads to use of the similar epithet cordaticollaris. As in the former name, this adjectival epithet is meant to signify the cordate pronotum.

Distribution and habitat

M. cordaticollaris is distributed in the Koa Mesic Forest lining the eastern margin of Kaupō Gap (Fig. 77). Specimens have been collected from 1170–1495 m elevation in litter including fern and moss humus plus koa leaves and phyllodes, as well as by beating low soft ferns and Pipturus (māmaki).

Mecyclothorax subconstrictus (Sharp)

Figs 62K, 73D, 74D, 76E–F, 79

Thriscothorax subconstrictus Sharp 1903: 259.

Mecyclothorax subconstrictus, Britton 1948b: 147.

Diagnosis

This, the third species of the group to exhibit setal formula 2 1 1 0 for at least some individuals, can be diagnosed from the other two—M. cordaticollis (Fig. 73B) and M. cordaticollaris (Fig. 73C)—by the following combination: 1, pronotal hind angles obtuse, lateral margin divergent from angle (Fig. 73D), not parallel before angle; 2, elytra broader relative to pronotal width, MEW/MPW = 1.53–1.66, versus values of 1.47–1.52 observed in specimens of the other two species; 3, elytral disc with mixture of isodiametric and transverse sculpticells, sculpticell breadth 2× length, versus more transverse meshes in the other two species. Setal formula 2 1 1(2) 0; individuals have a posterior dorsal elytral seta present unilaterally in rare instances. Standardized body length 3.7–4.3 mm.

Identification

(n = 5). The eyes are slightly larger and more convex than observed in M. cordaticollis and M. cordaticollaris—ocular ratio = 1.46–1.52, ocular lobe ratio = 0.81–0.88—though the ratios for the three species overlap. In aggregate the pronotal apex is broader relative to the base; APW/BPW = 1.03–1.09. The impressions of the anterior dorsal elytral setae span 2/3 of interval 3, whereas the impression of a posterior seta, if present, is small, spanning half or less of interval 3. The body coloration overall is also darker in specimens of this species versus those of the former two; 1, vertex and pronotal disc rufobrunneous with piceous cast; 2, pronotal lateral margins dark and concolorous with disc, though base and apex paler, rufoflavous.

Male genitalia (n = 1). Aedeagal median lobe robust, distance between parameral articulation and tip 2.9× depth at midlength (Fig. 76E); apex extended twice its depth beyond ostial opening, tip tightly rounded but with minute denticle along dorsal margin; median lobe slightly curved rightward in ventral view, left and right sides subparallel as they moderately converge to blunt-appearing tip (Fig. 76F); internal sac covered with dark microspicules, flagellar plate elongate, length 0.50× parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix broadly ellipsoid with constricted base, length 0.88 mm, breadth 0.44 mm, basal constriction at vagina 0.31 mm broad (Fig. 62K); bursal walls translucent with thin wrinkles; gonocoxite 1 with 2 short apical fringe setae and 4–6 small setae along medial surface (Fig. 74D); gonocoxite 2 broadly triangular with broadly rounded apex (apex worn), 2 lateral ensiform setae with apical seta longer and broader, apical nematiform setae on medial surface at 0.72× gonocoxite length.

Lectotype

(BMNH) hereby designated, left specimen on mounting platen, labeled: Thriscothorax subconstrictus Type D.S. Haleakala Perkins // Type // Hawaiian Is. Perkins 1904-336. // LECTOTYPE Thriscothorax subconstrictus Sharp J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat

Mecyclothorax subconstrictus is one of four species in the M. ovipennis group that occupy the highest elevations at the summit of Haleakalā (Figs 79, 80). Most specimens of these species were collected 9-iv-1894 during Perkins’ ascent of Haleakalā from Ukulele Camp. In Perkins’ words: “April 9th. Started with rug, food and gun etc. for Blackburn’s cave at about 9000 feet. I got there about 10 a.m. although I went down to nearly Olinda before ascending, as I wished to go on the usual trail. Worked from 9000 ft. to the summit. Got 3 or 4 species of Cyclothorax, the large punctured species as below, [i.e. Mecyclothorax montivagus, common from 4000–10000 ft.] the small ones all new to me apparently.” He returned to the summit two days later, collecting many more Mecyclothorax specimens. Besides M. subconstrictus, the species new to Perkins were M. pusillus and M. rusticus. These two collecting hikes occurred “a few weeks after the disappearance of the snow-cap (Perkins 1913, cxl).” Mecyclothorax subconstrictus was collected again in May and October 1896, the latter time at Holua in Haleakalā Crater. It has not been recollected since.

Mecyclothorax nubicola (Blackburn)

Figs 78A, 79

Cyclothorax nubicola Blackburn 1878b: 156.

Mecyclothorax nubicola, Sharp 1903: 244; Britton 1948b: 150.

Cyclothorax rupicola (lapsus calami), Blackburn and Sharp 1885: 216 (Sharp 1903: 244).

Diagnosis

This species is uniquely characterized by the very broad pronotum and the remarkably narrow, subparallel elytra (Fig. 78A); MEW/MPW = 1.31–1.36. The only other Haleakalā species to approach this conformation is M. pusillus (Fig. 78C). The pronotum of M. nubicola also distinctively diagnoses the species, with the hind angles represented by a slight widening of the lateral marginal bead, with the lateral margin only slightly sinuate anterad the very obtuse angle. Also, this species is composed of small beetles; standardized body length 3.4–3.5 mm. The setal formula of 2 2 2 2 is shared with the following three species; M. krushelnyckyi, M. pusillus, and M. rusticus. All four species also lack the parascutellar seta.

Figure 78.

Mecyclothorax ovipennis group species, dorsal habitus view. A M. nubicola (Leleiwi, 2650 m) B M. krushelnyckyi (Kahikinui, 2400 m) C M. pusillus (summit, 2895–3050 m) D M. rusticus (summit, 2895–3050 m).

Identification

(n = 3). The eyes are moderately convex; ocular ratio = 1.46–1.52, ocular lobe ratio 0.81–0.82. The pronotal disc is smooth, with a fine median longitudinal impression and moderately deep, finely incised anterior transverse impression. The median base contrasts to the disc as it is rugose, and is covered with ~10 densely distributed, elongate punctures each side, with fine longitudinal wrinkles at the base-disc juncture. The elytral basal groove is distinctly recurved laterally, with the humeral angle defined by a hitch at the base of the lateral marginal depression; MEW/HuW = 1.80–1.94. Discal elytral striae 1–3 are continuous, punctate, whereas stria 4 is interrupted along its length, and stria 5 is a series of punctures. Microsculpture is reduced in this species, with the frons and vertex glossy and covered with an obsolete transverse mesh. The pronotal disc has transverse lines in part, the cuticle glossy between these areas of microsculpture, whereas the pronotal median base is glossy medially, with irregular sculpticells laterally. The elytral disc bears very shallow isodiametric sculpticells in transverse rows.

Holotype

Female (BMNH): mounting platen with Blackburn Maui label (Zimmerman 1957: 210), Cyc nubicola (on reverse) // Type // Hawaiian Is. Rev. T. Blackburn 1888-30 // HOLOTYPE Cyclothorax nubicola Blackburn J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat

M. nubicola is a fourth summit-dwelling Mecyclothorax species, but it was not collected by Perkins in 1894 or 1896. The species is known from only four specimens and three localities (Fig. 79); the holotype described by Blackburn (1878b) from 10,000 ft. (3040 m), a Timberlake specimen (UCRC) from “gulch near Puu Nianiau, 6000 ft.” (1820 m; most probably the head of Waikamoi Gulch), and two specimens from Leleiwi Overlook, 2650 m elevation (P.D. Krushelnycky, CUIC, UHIM). The latter two specimens were collected in a pitfall trap in subalpine shrubland, though the summit record suggests also historical occupation of the alpine zone by this species.

Figure 79.

Recorded geographic distributions of M. ovipennis group species.

Mecyclothorax krushelnyckyi sp. n.

Figs 78B, 79

Diagnosis

This species (Fig. 78B) can be diagnosed from the other three small-bodied M. ovipennis group species with setal formula 2 2 2 2—M. nubicola (Fig. 78A), M. pusillus (Fig. 78C), and M. rusticus (Fig. 78D)–by: 1, the more narrowly constricted pronotal base; MPW/BPW = 1.54; 2, subellipsoid elytra, with the margin broadly rounded posterad the humerus, and the lateral margins evenly convex laterally; 3, elytra broad relative to forebody, with MEW/MPW = 1.51 and MEW/MHW = 2.15; and 4, the glossy upper body surface with little-developed microsculpture. The vertex is glossy, with obsolete transverse sculpticells, breadth 2× length in depressions. The pronotal disc is glossy, with obsolete transverse microsculpture visible in angled light; the pronotal base with obsolete transverse microsculpture over portions of the cuticle. The elytral disc is also glossy, with a transverse mesh, sculpticell breadth 2–3× length, restricted to the lateral and apical areas. Standardized body length 3.95 mm.

Description

(n = 1). Head capsule with frontal grooves broad near clypeus, lateral carina to anterior supraorbital seta; dorsal surface of neck slightly concave; eyes moderately developed, ocular ratio = 1.46, ocular lobe ratio = 0.78; labral anterior margin very shallowly emarginate apically; antennae filiform, antennomeres 2–3 with only 1–2 setae each along shafts; mentum tooth with sides acute, apex rounded. Pronotum transverse, MPW/PL = 1.28; hind angle sharply obtuse, lateral margin subparallel for short distance anterad angle; median base slightly depressed, ~10 punctures each side, punctures more elongate at juncture with disc; basal margin convexly expanded between laterobasal depressions; median longitudinal impression shallow, finely incised; anterior transverse impression deep, finely incised, area behind impression depressed relative to disc; anterior callosity convexly upraised, glossy; front angles slightly projected, rounded; pronotal apical width slightly greater than basal width, APW/BPW = 1.04; lateral marginal depression very narrow, edge appearing beaded except at front angle where margin is slightly broader; laterobasal depression narrow, continuous with lateral depression. Proepisternum with 5 minute punctures along hind marginal groove; prosternal process with narrow median impression, lateral margins broadly beaded between coxae. Elytra with disc flat, sides distinctly sloped; basal groove distinctly recurved to tightly rounded humeri, base relatively broad, MEW/HuW = 1.98; parascutellar seta absent; parascutellar striole with 4 punctures, striole shallow between punctures; sutural interval coplanar with lateral intervals basally, upraised apically; sutural and 2nd striae of subequal depth from base to apex; discal striae 1–5 minutely punctate, the punctures joined by depressed stria medially, striae 4–5 composed of isolated punctures, inner intervals slightly convex, lateral intervals flat; 8th interval slightly more convex than fused apical portion of striae 5 + 7; 2 dorsal elytral setae at 0.24–0.30× and 0.57× elytral length, setal impressions moderate, spanning 2/3 of interval 3; apical and subapical setae present; lateral elytral setae arranged in anterior series of 7 setae and posterior series of 6 setae; elytral marginal depression narrow from humerus to midlength, gradually reduced to beadlike margin at subapical sinuation; subapical sinuation shallow, more abruptly incurved anteriorly. Mesepisternum smooth; metepisternal width to length ratio 0.70; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1–5; suture between ventrites 2 and 3 complete; apical female ventrite with 4 equally spaced setae plus a median trapezoid of 4 subequal, short setae. Legs-metatarsomere 1/metatibial length ratio = 0.19; metatarsomere 4 length along outer lobe 1.33× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci shallow, narrow, median area broad. Microsculpture of metasternum a shallow transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous with piceous cast; antennomeres 1–3 flavous, 4–11 darker, more brunneous; pronotal disc rufopiceous; pronotal lateral margins very narrowly and base and apex rufoflavous; proepipleuron flavous, proepisternum rufopiceous; elytral disc rufopiceous, sutural interval rufous in basal half, rufoflavous in apical half, lateral marginal depression and apex of interval 9 rufoflavous; elytral epipleuron dorsally flavous, ventrally rufoflavous, metepisternum rufopiceous; abdomen with ventral ventrites 1–5 and base of 6 rufopiceous, apical 1/3 of ventrite 6 flavous; metafemur flavous; metatibia flavous, only tibial spines brunneous.

Female reproductive tract. The lone female holotype was not dissected.

Holotype

Female (UHIM) labeled: HI:Maui I. Haleakala / Kahikinui F.R. 2408 m el. / 20°41.93'N, W156°12.40', W / 24-XI-2008 P. Krushelnycky / Berlese shrubland litter // coll PDJ 627 / spec/lot# PKSP1463 // Mecyclothorax apicalis ? (PDK handwriting) // HOLOTYPE / Mecyclothorax / krushelnyckyi / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Etymology

This species is named to honor Dr. Paul Krushelnycky’s numerous, important discoveries of Mecyclothorax and Blackburnia species in the high elevation habitats of Haleakalā.

Distribution and habitat

M. krushelnyckyi is one of the few species known to occupy Haleakalā’s south slope (Fig. 79); the others known to do so being M. giffardi (Fig. 56), M. cordithorax (Fig. 89), and M. iteratus (Fig. 106). The single specimen was collected in a sift sample of shrubland litter at 2408 m elevation.

Mecyclothorax pusillus Sharp

Figs 62L, 74E, 76G–H, 78C, 80

Mecyclothorax pusillus Sharp 1903: 243; Britton 1948b: 147.

Diagnosis

Of the four M. ovipennis group species from Haleakalā with setal formula 2 2 2 2—M. nubicola (Fig. 78A), M. krushelnyckyi (Fig. 78B), M. rusticus (Fig. 78D), and this species (Fig. 78C)–M. pusillus can be diagnosed by : 1, pronotal base moderately broad, MPW/BPW = 1.39–1.48; 2, pronotal hind angles projected, obtuse, the lateral margin subparallel for twice the distance of the basal articulatory socket; 3, elytra narrow relative to head, MEW/MHW = 1.85–1.93, with sides subparallel, MEW/HUW = 1.84–1.90, the humerus tightly rounded; 4, frons and vertex with evident shallow transverse-mesh microsculpture, sculpticell breadth 2–3× length. Standardized body length 3.3–3.9 mm.

Identification

(n = 5). The head is broad with large eyes that cover much of the ocular lobe, ocular lobe ratio = 0.84–0.88, though the broad frons results in an ocular ratio lower than might be expected based on the eye size; ocular ratio = 1.45–1.48. Antennomeres 5–11 are stout, relatively short, of moniliform conformation similar to observed in M. nubicola. The pronotum is slightly transverse, MPW/PL = 1.19–1.29, with the base moderately constricted; MPW/BPW = 1.43–1.51. The pronotal median base is glossy due to the lack of microsculpture, but irregularly punctate with ~20 punctures each side, the punctures more elongate at juncture with disc. Elytral intervals 2–4 are nearly flat on the disc, though interval 2 is convex to the elytral apex, the sutural and 2nd striae of subequal depth. The discal striae 2–4 are discontinuous, with their punctures isolated for portions of the strial length. The pronotal and elytral microsculpture are extremely similar to that observed in M. rusticus: 1, pronotal disc with obsolete transverse mesh, glossy medially, with sculpticell breadth 2–3× length laterally; 2, elytral disc with shallow isodiametric and transverse sculpticells in transverse rows, the elytral apex with an isodiametric mesh.

Male genitalia (n = 1). Aedeagal median lobe slender, distance between parameral articulation and tip 5.5× depth at midlength (Fig. 76G), lobe angled basally with median shaft straight; apex distinctly downturned, tip rounded; median lobe distinctly curved rightward toward apex in ventral view (Fig. 76H), right and left margins slightly convergent to blunt tip in this view; internal sac with fine spicules only, flagellar plate (visible in ventral view, Fig. 76H) short, length 0.34× parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix columnar with rounded apex, length 0.46 mm, breadth 0.17 mm (Fig. 62L); bursal walls translucent with thin wrinkles, apex thinner, more diaphanous; gonocoxite 1 with 3 apical fringe setae, the middle seta larger, and 3–4 smaller setae along medial surface (Fig. 74E); gonocoxite 2 falcate with tightly rounded apex, base broadly extended laterally, 2 lateral ensiform setae with apical seta broader, apical nematiform setae on medial surface at 0.69× gonocoxite length.

Lectotype

Male (BMNH) hereby designated, labeled: Thriscothorax pusillus Type D.S. Haleakala Perkins 254 // Type // Hawaiian Is. Perkins 1904-336. //LECTOTYPE Thriscothorax pusillus Sharp J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat

M. pusillus is the second of Perkin’s 19th Century high-elevation Mecyclothorax triplet, with all of his records from his collecting activities made on his trips to the summit; 1830–3050 m elevation (Fig. 80). A single recent record (Kalahaku Overlook, 2870 m elevation, P.D. Krushelnycky, BPBM) places a lower-elevation population of this species in sympatry with Argentine Ant (Liebherr and Krushelnycky 2007).

Figure 80.

Recorded geographic distributions of M. ovipennis group species.

Mecyclothorax rusticus Sharp

Figs 74F, 76I–J, 78D, 80

Mecyclothorax rusticus Sharp 1903: 244; Britton 1948b: 151.

Diagnosis

Individuals of this species (Fig. 78D) are most like those of M. pusillus (Fig. 78C), and they are best diagnosed by the broader, more convexly margined elytra. The basal groove is recurved evenly on the rounded humeri, not tightly rounded to subangulate as in M. pusillus. Also, the head is narrow relative to the elytra; MEW/MHW = 2.02–2.07, with slightly more elongate antennomeres. The discal elytral striae are deeper and more continuous than in M. pusillus, though the lateral striae are more similar between the species; striae 5–6 discontinuous, stria 7 a series of minute punctures. The pronotal median base is little depressed relative to the disc, and is covered with ~10 isolated, elongate punctures each side, the surface glossy between the punctures. Finally, the vertex is glossy, with only an obsolete transverse mesh visible in angled light, sculpticell breadth 2–3× length. Setal formula 2 2 2 2. Standardized body length 3.7–4.3 mm.

Identification

(n = 5). The eyes are less convex than in individuals of M. pusillus, but due to the narrower head, the ocular ratio = 1.50–1.53; slightly greater than measured for that species. The pronotum is moderately constricted basally; MPW/BPW = 1.42–1.49. However the base is relatively broad, APW/BPW = 0.91–0.97, versus the subequal apical and basal pronotal widths in M. pusillus. The pronotal disc is glossy, with an obsolete transverse mesh, sculpticell breadth 2–3× length. The pronotal median base also glossy with shallow isodiametric sculpticells laterally between the punctures. The elytral disc bears shallow isodiametric and transverse sculpticells, breadth 2× length, in transverse rows, whereas the elytral apex is covered with shallow isodiametric sculpticells in transverse rows.

Male genitalia (n = 1). Aedeagal median lobe slender, distance between parameral articulation and tip 5.2× depth at midlength (Fig. 76I); apex nearly as broad as median shaft until it curves ventrally to narrow, blunt tip; median lobe sinuously curved apically in ventral view, right margin distinctly and briefly concave, left margin with incurved hitch near bluntly rounded tip (Fig. 76J); internal sac without ornamentation, flagellar plate short (visible in ventral view, Fig. 76J), length 0.29× parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix columnar, length 0.46 mm, breadth 0.22 mm basally at vagina, 0.11 mm near rounded apex (a slightly broader version of M. pusillus bursa, Fig. 62L); bursal wall translucent with thin wrinkles; gonocoxite 1 with 2 short apical fringe setae and 4–6 shorter setae on medial surface (Fig. 74F); gonocoxite 2 falcate with broadly rounded apex (worn?), 2 short, broad lateral ensiform setae (also worn?), apical nematiform setae on medial surface at 0.73× gonocoxite length.

Lectotype

Male (BMNH) hereby designated, labeled: Mecyclothorax rusticus Type D.S. Haleakala Perkins 254 // Type // Hawaiian Is. Perkins 1904-336. // Haleakala Maui 9½–10000 ft. Perkins IV-1894 // LECTOTYPE Mecyclothorax rusticus Sharp J.K. Liebherr 1998 (black-margined red label).

Distribution and habitat

M. rusticus has been collected only by R.C.L. Perkins, with localities ranging 2895–3050 m elevation along his trips to the summit, and also at Holua, 2100–2200 m elevation at the western margin of Haleakalā Crater (Fig. 80).

Mecyclothorax argutor species group

Diagnosis. These are large-bodied species, nearly all individuals with standardized body length > 4.75 mm (only very few individuals of the very abundant and geographically widespread M. cordithorax with body length 4.5–4.7 mm). All species are characterized by presence of all major setae; 1, both anterior and posterior supraorbital setae; 2, lateral and basal pronotal setae; 3, parascutellar seta; 4, both anterior and posterior dorsal elytral setae, and in two species extra setae in 3rd interval; 5, both apical and subapical elytral setae; and 6, the full complement of lateral elytral setae, i.e. an anterior series of seven setae and a posterior series of six setae. Thus the base setal formula for species in the group is 2 2 2 2. The eyes may be very small, flat, and covering little of the ocular lobe (Figs 81A, D, 87C), or moderately developed (81B–C, 87A–B, 87D), although in the latter set of species there may be substantial infraspecific variation in eye development, with some of the individuals exhibiting smaller, flatter eyes.

Membership and distribution. This group exhibits the greatest diversity on Haleakalā with the eight species treated below. Moloka‘i supports six species (Liebherr 2007), and West Maui (Liebherr 2011) and the island of Hawai‘i (Liebherr 2008b) each host two species.

Key to adults of the Mecyclothorax argutor species group, Haleakalā volcano, Maui, Hawai‘i

1 Eyes moderately small to large, outer surface convex or positioned on ocular lobe so that inner dorsal margins converge on frons (Figs 81B–D, 87), ocular ratio = 1.39–1.53; elytra with shallow to well-developed isodiametric to transverse microsculpture, surface reflective; dorsal body coloration medially dark brunneous to piceous 2
1’ Eyes small, flat, ocular ratio = 1.29–1.35 (Fig. 81A); elytra with granulate isodiametric microsculpture, surface appearing rough, matte; dorsal body coloration pale brunneous (062) M. ommatoplax sp. n.
2(1) Elytra paler marginally, intervals 8–9 flavous, contrasted with piceous intervals 2–7 assessed on disc (Fig. 81B–C); discal elytral intervals flat to slightly convex 3
2’ Elytra concolorous except for possibly paler lateral marginal depression (Figs 81D, 87); discal elytral intervals moderately convex, associated striae well defined, moderately to distinctly punctate 4
3(2) Elytral disc with evident isodiametric sculpticells in transverse rows; pronotal lateral margins narrowly flavous, depressed median base concolorous with disc; standardized body length 5.1–5.4 mm (063) M. semistriatus sp. n.
3’ Elytral disc with distinctly transverse-mesh microsculpture (some sculpticells may be of subequal breadth and length near midline, but all are broader laterally on intervals 3–5 where they may be 4× broad as long); pronotal lateral margins broadly flavous, depressed median base distinctly paler than disc; standardized body length 4.8 mm (064) M. refulgens sp. n.
4(2) Pronotal lateral margins subparallel to briefly convergent anterad atmost slightly projected hind angles, lateral marginal depression narrow at midlength, front angle moderately projected anteriorly (Fig. 87); eyes larger, dorsal inner margins not convergent on frons 5
4’ Pronotal lateral margins distinctly convergent anterad acute, projected hind angles, pronotal lateral margins broad, front angle explanately projected anteriorly (Fig. 81D); eyes small, dorsal inner margins convergent on frons (065) M. argutulus sp. n.
5(4) Sutural interval elevated into a callus near elytral midlength, intervals 2–4 distinctly, broadly depressed near anterior dorsal seta (Fig. 87A–B) 6
5’ Sutural interval of similar convexity to other intervals near elytral midlength, intervals 2-4 at same elevation as sutural interval near anterior dorsal seta, or discal surface slightly depressed in vicinity of anterior seta (Fig. 87C–D) 7
6(5) Pronotal apex and base of subequal width (Fig. 87A), APW/BPW = 1.02–1.05; male aedeagal median lobe with pointed apex (Figs 82E, G–H) (066) M. planipennis sp. n.
6’ Pronotal apex broader than base (Fig. 87B), APW/BPW = 1.06–1.15; male aedeagal median lobe with rounded apex (Fig. 82I, K–L) (067) M. planatus sp. n.
7(5) Body narrower, MPW/PL = 1.19–1.22 (Fig. 87C); pronotal anterior transverse impression deep, smooth, defining a smooth, broadly convex anterior callosity; male aedeagal median lobe with narrow, elongate apex with tightly rounded, downturned tip (Fig. 88A–B) (068) M. argutuloides sp. n.
7’ Body broader, MPW/PL = 1.25–1.38 (Fig. 87D); pronotal anterior transverse impression shallow, broad, the impression and anterior callosity crossed by fine longitudinal wrinkles; male aedeagal median lobe with short, broad apex that terminates in a pointed or tightly rounded tip (Fig. 88C–I) (069) M. cordithorax Liebherr

Mecyclothorax ommatoplax sp. n.

Figs 81A, 85

Diagnosis

This species is easily distinguished by the very small, little convex eyes; ocular ratio = 1.29–1.35, ocular lobe ratio = 0.68–0.69, in combination with the granulate isodiametric elytral microsculpture (Fig. 81A). Setal formula 2 2 2 2. Among species of the M. argutor group, the beetles are of moderate size, standardized body length 4.8–5.5 mm.

Figure 81.

Mecyclothorax argutor group species, dorsal habitus view. A M. ommatoplax (Kīpahulu, 1500 m) B M. semistriatus (Honomanu, 1950 m) C M. refulgens (Kīpahulu, 1860 m) D M. argutulus (Kuhiwa, 1615 m).

Description

(n = 2). Head capsule with frontal grooves broad near clypeus, curved laterally near clypeal juncture, a straight ridgelike lateral carina extended from dorsal mandibular articulation to mesad anterior supraorbital seta; dorsal surface of neck flat to slightly convex; compound eye with approximately 12–13 ommatidia across the maximal horizontal diameter; labral anterior margin medially emarginate 0.2× length; antennae filiform, antennomere 3 with sparse, short setae; mentum tooth with sides acute, apex pointed. Pronotum slightly transverse, MPW/PL = 1.17–1.27, constricted basally, MPW/BPW = 1.51–1.58; hind angle right, apex rounded, lateral margin parallel anterad angle; median base depressed relative to disc, covered with rugose wrinkles and round punctures; basal margin broadly, medially extended between laterobasal depressions; median longitudinal impression fine, shallow, crossed by shallow wrinkles; anterior transverse impression broad, shallow, crossed by longitudinal wrinkles; anterior callosity slightly convex, crossed by longitudinal wrinkles from anterior impression; front angles not projected, rounded; pronotal anterior width slightly greater than basal width, APW/BPW = 1.02–1.05; lateral marginal depression narrow, margin upturned to beaded; laterobasal depression moderately broad with low oblique ridge terminated at hind angle. Proepisternum with 6 punctures along hind marginal groove; prosternal process medially concave, margin smoothly upraised. Elytra subquadrate, narrow basally, the basal groove meeting lateral marginal depression at subangulate humerus, MEW/HuW = 1.81–1.94; disc flat, sides moderately depressed; parascutellar seta present; parascutellar striole shallow, smooth, continued onto base; sutural interval slightly more convex than lateral intervals; sutural and 2nd striae of subequal depth from base to apex; discal striae 1–5 continuous, slightly irregular but impunctate, deeper and smooth apically, stria 6 reduced, stria 7 traceable, very shallow, associated intervals broadly, slightly convex; 8th interval slightly convex laterad 7th stria, principally due to deep apical portion of 7th stria; 2 dorsal elytral setae at 0.30× and 0.59–0.60× elytral length, setal impressions shallow, about breadth of interval 3; apical and subapical setae present; lateral elytral setae arranged as anterior series of 7 setae and posterior series of 6 setae; elytral marginal depression moderately broad, lined with sculpticells, the margin upturned; subapical sinuation evident, abrupt and brief. Mesepisternum with ~14 punctures in 2–3 rows, metepisternal width to length ratio = 0.67; metepisternum/metepimeron suture distinct. Abdomen with shallow indistinct wrinkles on ventrites 1–3, suture between ventrites 2 and 3 complete; apical female ventrite with 4 equally spaced setae and median trapezoid of 4(–5 unilaterally) subequal, short setae. Legs-metatarsomere 1/metatibial length ratio = 0.19; metatarsomere 4 length along outer lobe 1.4× medial tarsomere length, with apical and subapical setae; metatarsal dorsolateral sulci broad, shallow. Microsculpture of vertex an upraised isodiametric mesh in transverse rows; pronotal disc with transverse mesh, median base with granulate isodiametric mesh; elytral apex with distinct transverse mesh; metasternum with distinct transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous; antennomere 1 flavous, 2–11 rufoflavous; pronotal disc rufobrunneous, lateral margins narrowly paler in lateral depression, rufoflavous; proepipleuron rufoflavous, proepisternum rufobrunneous with piceous cast; elytral disc reflective rufobrunneous, sutural interval basally rufous, apically flavous, elytral margins broadly rufoflavous, apex broadly rufoflavous to flavous; elytral epipleuron flavous, metepisternum rufobrunneous with piceous cast; abdomen rufobrunneous with piceous cast, apical half of ventrite 6 broadly paler, flavous; metafemur flavous; metatibia rufoflavous.

Female reproductive tract. The holotype and paratype females were not dissected.

Holotype

Female (CUIC) labeled: HI:Maui Haleakala N.P. / Kipahulu Vy.1500 m el. / 9-V-1991 sifting / leaf litter by day // S. Jessel / A.C. Medeiros, / Jr. collectors // Mecyclothorax / ommatoplax / ♀ photo / det. J.K. Liebherr 2014 // HOLOTYPE / Mecyclothorax / ommatoplax / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratype

HI: Maui, Kipahulu Vy., West Camp at Dead Pig Bog, 2010 m el., 18-iii-1998, Takumi (BPBM, 1).

Etymology

The species epithet compounds the Greek words plax, flat round plate, and ommatos, the genitive of omma, i.e. eye. As Greek, ommatoplax is treated as a noun. The epithet refers to the very flat eyes characteristic of this species.

Distribution and habitat

M. ommatoplax is distributed in the upper reaches of Kīpahulu Valley (Fig. 85). Specimens have been collected in sift samples of leaf and humus litter.

Mecyclothorax semistriatus sp. n.

Figs 81B, 82A–B, 83A, 84A, 85

Diagnosis

This (Fig. 81B) and the following M. refulgens (Fig. 81C) synapomorphously exhibit pale, flavous elytral margins that contrast with the piceous elytral disc. Beetles of this species have broader bodies, with the pronotum more transverse, MPW/PL = 1.21–1.32, and the elytra more broadly ellipsoid, the greatest width just behind midlength. Cuticular microsculpture is less developed in this species, the vertex covered with shallow isodiametric sculpticells in transverse rows, the elytral disc covered with a shallow, elongate transverse mesh, sculpticell breadth 2–3× length. Also, beetles of this species are larger than those of M. refulgens; standardized body length 5.1–5.4 mm. Setal formula 2 2 2 2.

Description

(n = 5). Head capsule with frontal grooves broad and moderately deep near clypeus, bordered laterally by broad carina to supraorbital seta; dorsal surface of neck flat to convex; eyes convex, of moderate size, ocular ratio = 1.39–1.47, ocular lobe ratio = 0.76–0.80; labral anterior margin broadly, shallowly emarginate; antennae filiform, antennomere 3 sparsely setose; mentum tooth with sides acute, apex tightly rounded. Pronotum cordate, lateral margins distinctly sinuate basally, hind angles acute, projected, MPW/BPW = 1.53–1.61; median base depressed relative to disc, with ~12 rounded punctures and sinuous depressions each side; basal margin slightly convex medially; median longitudinal impression fine, shallow, anterior transverse impression moderately deep, narrow, longitudinal wrinkles fore and aft; anterior callosity slightly convex, with indistinct longitudinal wrinkles; front angles slightly projected, tightly rounded; pronotal apex variably as broad as base, APW/BPW = 0.98–1.11; lateral marginal depression narrow throughout, margin upraised to beaded; laterobasal depression narrow, with low oblique ridge terminated at hind angle. Proepisternum with 6 punctures along hind marginal groove; prosternal process medially concave, margin smoothly upraised. Elytra moderately convex, disc narrowly flattened medially; basal groove recurved at tightly rounded humeral angle, MEW/HuW = 2.0–2.22; parascutellar seta present; parascutellar striole with 4 punctures, shallow between punctures; sutural interval of same convexity as intervals 2–3; sutural and 2nd striae of subequal depth from base to apex; discal striae 1–3 shallow with small but evident punctures, lateral striae 4–6 shallower, traceable as isolated serial punctures, stria 7 obsolete except at elytral apex where it is broad and shallow; 8th interval as convex as fused apical portion of striae 5 + 7; 2 dorsal elytral setae at 0.23–0.27× and 0.57–0.69× elytral width, setal impressions shallow, spanning ½ width of interval 3; apical and subapical setae present; lateral elytral setae arranged in anterior series of 7 setae and posterior series of 6 setae; elytral marginal depression moderately broad, lined with sculpticells, margin upturned; subapical sinuation shallow, nearly obsolete. Mesepisternum with ~9 punctures in 2–3 rows; metepisternal width to length ratio = 0.78; metepisternum/metepimeron suture distinct. Abdomen with shallow indistinct lateral wrinkles on ventrites 1–3; suture between ventrites 2 and 3 complete; apical male ventrite with 2 marginal setae and apical female ventrite with 4 equally spaced setae plus median trapezoid of 4 subequal, short setae. Legs-metatarsomere 1/metatibial length ratio = 0.18; metatarsomere 4 length along outer lobe 1.4× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci broad, shallow. Microsculpture of pronotal median base of distinct isodiametric sculpticells in transverse rows; elytral apex with distinct transverse mesh; metasternum with shiny transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous; antennomeres 1–4 flavous, 5–11 rufobrunneous; pronotal disc rufobrunneous, margins narrowly rufoflavous; proepipleuron rufoflavous, proepisternum rufobrunneous; elytral disc reflective rufopiceous, sutural interval rufous basally, flavous apically; elytral margins broadly paler, with intervals 7–9 or 8–9 rufoflavous near interval 6 to flavous laterally, apex broadly flavous apicad subapical sinuation; elytral epipleuron flavous with rufous cast, metepisternum rufobrunneous with piceous cast; abdomen with ventrites 1–2 piceous, 3–5 rufoflavous, 6 broadly flavous; metafemur flavous, metatibia rufoflavous.

Male genitalia (n = 1). Aedeagal median lobe robust, distance from parameral articulation to tip 3.2× depth at midlength (Fig. 82A); apex narrowed distad ostial opening, tip expanded dorsally, knoblike; median lobe distinctly curved rightward near apex in ventral view (Fig. 82B), left margin indented before parallel-sided, bluntly rounded tip; internal sac with small dorsal ostial microtrichial patch (left patch in Fig. 82B) and larger ventral ostial patch; flagellar plate of moderate size, length 0.38× parameral articulation-tip distance.

Figure 82.

Male aedeagus, M. argutor group species (for abbreviations see Table 2, p. 23). A–B M. semistriatus, right and ventral views (Honomanu, 1950 m) C–D M. argutulus, right and ventral views (Kuhiwa, 1615 m) E–H M. planipennis. E–F Right and ventral views (Kīpahulu, 1960 m). G–H Right view, sac everted. G (ESE Kuiki, 2145 m) H (Kīpahulu, 1960 M) I–L M. planatus I–J Right and ventral views (Honomanu, 1820 m) K–L Right and left views, sac everted (Waikamoi, 1470 m).

Female reproductive tract (n = 1). Bursa copulatrix columnar with rounded apex, length 0.82 mm, breadth 0.37 mm (Fig. 83A); bursal walls translucent, smooth with a few wrinkles; gonocoxite 1 with 4 apical fringe setae, the middle two setae larger, 1 small seta basad apicomedial angle, 5–7 smaller setae on medial surface (Fig. 84A); gonocoxite 2 broadly falcate, base broadly extended laterally, 2 stout, apically narrowed lateral ensiform setae, apical nematiform setae on medial surface at 0.80× gonocoxite length.

Figure 83.

Female bursa copulatrix and associated reproductive structures, M. argutor group species, ventral view (for abbreviations see Table 2, p. 23). A M. semistriatus (Honomanu, 1950 m) B M. planipennis (ESE Kuiki, 2145 m) C M. planatus (Honomanu, 1700 m) D M. argutuloides (Kīpahulu, 2100 m) E M. cordithorax (Kaupō Gap, 1736 m). Scale bar = 0.50 mm.

Figure 84.

Left female gonocoxa, M. argutor group species, ventral view. A M. semistriatus (Honomanu, 1950 m) B M. planipennis (ESE Kuiki, 2145 m) C M. planatus (Honomanu, 1700 m) D M. argutuloides (Kīpahulu, 2100 m) E M. cordithorax (Kaupō Gap, 1736 m).

Holotype

Male (CAS) labeled: U.S.A. Hawaii: Maui, / Haleakala nw. slope / Waikamoi Reserve / Transect 3, 1950 m, / 7 May 1991, Stop #91-10B / D.H. Kavanaugh collector // D.H. Kavanaugh / collection // 2 // HOLOTYPE / Mecyclothorax / semistriatus / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes

Same data as holotype (CAS, 2; CUIC, 2).

Etymology

The adjectival species epithet semistriatus refers to the medially striate and laterally smooth elytra.

Distribution and habitat

The type series of M. semistriatus was found in moss adhering to tall mastlike ‘ōhi‘a trees in the upper Honomanu drainage, 1950 m elevation (Fig. 85). The ‘Ōhi‘a Mesic Forest is quite open here, with the moss layers rather thin, though they were moist at the time of collecting.

Figure 85.

Recorded geographic distributions of M. argutor group species.

Mecyclothorax refulgens sp. n.

Figs 81C, 85

Diagnosis

This and M. semistriatus, comprise the pair of M. argutor group species characterized by contrastingly pale elytral margins and shallow elytral striae. This species (Fig. 81C) can be told from M. semistriatus (Fig. 81B) by the broadly paler pronotal and elytral lateral margins, and the basally narrower elytra, the elytral shape distinctly ovoid with the greatest width well behind midlength. Also, beetles of this species exhibit more well-developed microsculpture, with the elytral disc subiridescent due to the well-developed transverse and isodiametric sculpticells. The discal elytral striae are less punctate in this species, with only the sutural stria punctate basally, striae 2–5 at most slightly irregular. The sutural and 2nd striae are of subequal depth only at the extreme apex of the elytra. More basally the sutural stria is broader and deeper. Setal formula 2 2 2 2. Standardized body length 4.8 mm.

Description

(n = 1). Head capsule with frontal grooves broad near clypeus, a sinuous lateral carina extended to anterior supraorbital seta; dorsal surface of neck flat; eyes moderately convex, ocular lobe moderately protruded from gena, ocular ratio = 1.46, ocular lobe ratio = 0.79; labral anterior margin broadly, shallowly emarginate; antennae filiform, antennomere 3 sparsely setose; mentum tooth with sides acute, apex tightly rounded. Pronotum cordate, little transverse, MPW/PL = 1.19, lateral margins distinctly sinuate before very slightly acute, projected hind angles; pronotal base narrow, MPW/BPW = 1.63; median base depressed relative to disc, 12–14 punctures laterally plus wrinkles present along juncture with disc; basal margin straight; median longitudinal impression fine, very shallow; anterior transverse impression broad, shallow medially, crossed by longitudinal wrinkles, deep, continuous in lateral 2/3; anterior callosity slightly convex, longitudinal wrinkles indistinct; front angles slightly projected, tightly rounded; pronotal apical width greater than basal width, APW/BPW = 1.10; lateral marginal depression narrow throughout, margin upturned to beaded; laterobasal depression moderately broad, slightly raised medially. Proepisternum with 6 punctures along hind marginal groove; prosternal process medially concave, margin smoothly upraised. Elytra convex, sides depressed; basal groove meeting lateral marginal depression at subangulate humerus; elytra narrow basally, MEW/HuW = 2.10; parascutellar seta present; parascutellar striole shallow, smooth, with 1–2 punctures; sutural interval more convex than lateral intervals, the sutural juncture upraised; sutural stria deeper and more punctate than 2nd stria on disc, discal striae 3–5 traceable, smooth, stria 6 obsolete, stria 7 absent, associated intervals broadly, slightly convex on disc, flat laterally; 8th interval laterad position of 7th stria not more convex than more medial elytral surface; 2 dorsal elytral setae at 0.23–0.29× and 0.66× elytral length, setal impressions shallow, broad, spanning interval 3; apical and subapical setae present; lateral elytral setae arranged in anterior series of 7 setae and posterior series of 6 setae; elytral marginal depression narrow, margin upturned; subapical sinuation shallow, broad. Mesepisternum with ~8 punctures in 2–3 rows; metepisternal width to length ratio = 0.79; metepisternum/metepimeron suture distinct. Abdomen with shallow, indistinct lateral wrinkles on ventrites 1–3; suture between ventrites 2 and 3 complete; apical female ventrite with 4 equally spaced setae and median pair of 2 small setae along ventrite margin. Legs-metatarsomere 1/metatibial length ratio = 0.18; metatarsomere 4 length along outer lobe 1.4× medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci narrow, canaliculated, median carina broad. Microsculpture of vertex isodiametric sculpticells in transverse rows; pronotal disc with transverse mesh and parallel lines, median base with distinct isodiametric sculpticells; elytral apex covered with reflective transverse mesh; metasternum with reflective transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufobrunneous with piceous cast; antennomeres 1–3 flavous, 4-11 rufobrunneous; pronotal disc rufopiceous, lateral margins and pronotal base broadly rufoflavous; proepipleuron rufoflavous, proepisternum rufobrunneous with piceous cast; elytral disc reflective rufopiceous, sutural interval rufous basally, flavous apically; elytral margins broadly paler, intervals 8–9 rufoflavous to flavous at marginal depression, elytral apex broadly rufoflavous to flavous apicad subapical sinuation; elytral epipleuron flavous, metepisternum rufobrunneous with piceous cast; abdomen with ventrites 1–2 and base of 3 piceous, apex of 3 rufoflavous, ventrites 4–6 flavous; metafemur flavous; metatibia rufoflavous.

Female reproductive tract. The lone female specimen was not dissected.

Holotype

Female (BPBM) labeled: HAWAIIAN IS.: Maui I: / Kipahulu Valley: West Camp; / 12.vii.1983 // at night on tree trunks / F.G. Howarth, Col. / BISHOP Museum // HOLOTYPE / Mecyclothorax / refulgens / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Etymology

The dorsal body surface of these beetles is quite reflective, leading to use of the present participle of the Latin verb refulgeo—to shine—as the species epit