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).

(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 2^nd 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; 8^th interval laterad 7^th 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).

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).

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).

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.

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.

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.

(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.

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

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.

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.

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.

(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.

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

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.

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).

(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).

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).

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.

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].

(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 2^nd striae of subequal depth from base to apex; all striae deep, associated intervals convex; 7^th and 8^th 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.

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).

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).

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

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).

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.

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.

(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 2^nd 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; 7^th and 8^th interval similarly convex mesad subapical sinuation; 2 dorsal elytral setae at 0.29× and 0.59× elytral length, setal impressions spanning 3^rd 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.

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).

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).

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).

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).

(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 3^rd 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 2^nd 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; 7^th and 8^th 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).

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).

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).

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

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).

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.

(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 2^nd 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; 7^th and 8^th 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.

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).

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).

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

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.

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.

(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 2^nd 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.

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.

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).

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.

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.

(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 2^nd striae of subequal depth from base to apex; discal striae 1–7 with small punctures that cause strial irregularities; 7^th and 8^th 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 5^th 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).

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).

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).

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

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.

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.

(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.

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).

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.

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).

(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.

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).

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 19^th Century.

Figure 25. 

Recorded geographic distributions of M. obscuricornis group species.

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).

(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 2^nd striae of subequal depth and punctation from base to apex; striae 1–6 and 8 complete, stria 7 shallower, associated intervals convex; 7^th and 8^th 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).

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).

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).

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).

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).”

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.

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.

(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.

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).

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).

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.

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.

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.

(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.

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).

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).

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.

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.

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 8^th 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).

(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).

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

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.

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.

(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 2^nd 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; 7^th and 8^th 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.

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).

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).

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

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).

(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.

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).

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.

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.

(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 2^nd 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; 7^th and 8^th 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.

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).

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.

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.

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.

(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 2^nd 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; 7^th and 8^th 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.

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).

261 specimens (see Appendix).

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

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.

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 8^th 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.

(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.

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

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.

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.

(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 2^nd striae of subequal depth from base to apex; sutural and lateral discal striae 2–6 minutely punctate, striae slightly irregular along length; 7^th and 8^th 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).

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).

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

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.

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.

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).

(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.

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).

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).

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.

(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 2^nd 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; 7^th and 8^th 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.

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).

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).

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.

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.

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.

(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.

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).

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.

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).

(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 2^nd striae of subequal depth from base to apex; discal striae minutely punctured in basal 1/3, smooth and deep apically, associated intervals convex; 7^th and 8^th 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.

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).

176 specimens (see Appendix).

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.

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.

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).

(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).

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).

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).

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.

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.

(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 2^nd striae of subequal depth from base to apex; discal striae with small punctures that cause strial irregularities along length, intervals convex; 7^th and 8^th 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).

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).

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

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.

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.

(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).

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

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.

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.

(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 2^nd 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; 7^th and 8^th 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.

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).

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).