The integripennis species group of Geocharidius Jeannel, 1963 (Carabidae, Bembidiini, Anillina) from Nuclear Central America: a taxonomic review with notes about biogeography and speciation

Igor M. Sokolov; David H. Kavanaugh

doi:10.3897/zookeys.443.7880

Abstract

Our review recognizes 15 species of the integripennis species group of Geocharidius from Nuclear Central America, include three species previously described (G. gimlii Erwin, G. integripennis (Bates) and G. zullinii Vigna Taglianti) and 12 described here as new. They are: G. andersoni sp. n. (type locality: Chiapas, Chiapas Highlands, Cerro Huitepec) and G. vignatagliantii sp. n. (type locality: Chiapas, Motozintla, Sierra Madre de Chiapas, Benito Juárez) from Mexico; G. antigua sp. n. (type locality: Sacatepéquez, 5 km SE of Antigua), G. balini sp. n. (type locality: Suchitepéquez, 4 km S of Volcan Atitlán), G. erwini sp. n. (type locality: Quiché Department, 7 km NE of Los Encuentros), G. jalapensis sp. n. (type locality: Jalapa Department, 4 km E of Mataquescuintla), G. longinoi, sp. n. (type locality: El Progreso Department, Cerro Pinalón), and G. minimus sp. n. (type locality: Sacatepéquez Department, 5 km SE of Antigua) from Guatemala; and G. celaquensis sp. n. (type locality: Lempira Department, Celaque National Park), G. comayaguanus sp. n. (type locality: Comayagua Department, 18 km ENE of Comayagua), G. disjunctus sp. n. (type locality: Francisco Morazán, La Tigra National Park), and G. lencanus sp. n. (type locality: Lempira Department, Celaque National Park) from Honduras. For all members of the group, adult structural characters, including male and female genitalia, are described, and a taxonomic key for all members of the integripennis species group is presented based on these characters. Behavioral and biogeographical aspects of speciation in the group are discussed, based on the morphological analysis. In all cases of sympatry, pairs of closely related species show greater differences in sizes than pairs of more remotely related species. Integripennis group species occupy six different montane areas at elevations above 1300m, with no species shared among them. Major faunal barriers in the region limiting present species distributions include the Motagua Fault Zone and a gap between the Guatemalan Cordillera volcanic chain and the Honduran Interior Highlands no higher than 900m in elevation. Highest species diversity is in the Guatematan Cordillera (six species), second highest in the Honduran Interior Highlands area (four species).

Keywords

Coleoptera , Adephaga , Carabidae , Bembidiini , Anillina , Geocharidius , new species, Nuclear Central America, Motagua Fault Zone, biogeography, sympatric speciation

Introduction

Geocharidius Jeannel, 1963 was established for a Guatemalan species, G. integripennis (Bates), described in “Biologia Centralia-Americana” (Bates 1882). Jeannel’s description of Geocharidius omitted or misinterpreted several important morphological details, leading Vigna Taglianti (1973) to re-describe the genus on the basis of the two species, G. integripennis and G. zullinii Vigna Taglianti, known to him at that time. Providing new evidence, Vigna Taglianti (l.c.) proposed a new phyletic lineage for Geocharidius, which had been placed by Jeannel (1963) in a lineage with the Mediterranean Geocharis Ehlers and Rhegmatobius Jeannel. The new lineage integrated the New World anillines of Jeannel’s “scotodipnienne” stock of genera (i.e. those taxa, members of which have a mental tooth along with the umbilicate series of elytral pores of type B (Jeannel 1937), where pores 7 and 8 and 8 and 9 are separated from each other by equal distances. According to Vigna Taglianti (1973) this lineage included also Mexanillus Vigna Taglianti, described in the same paper, and perhaps also Mystroceridius Reichardt (1970) from the Galapagos Islands. Since then, several new genera of the “scotodipnienne” stock of anilline genera have been described from the New World (Zaballos 1997; Mateu and Etonti 2002). At present, Geocharidius includes 5 species (Lorenz 2005; Zaballos 2004), four of which are limited in their distribution to Guatemala (Erwin 1982). Ecologically, representatives of Geocharidius are adapted for life in forest litter, and these beetles are comparatively easy to collect using litter sifting techniques.

From 2008 to 2011, the “Leaf Litter Arthropods of Mesoamerica” (LLAMA) project (http://llama.evergreen.edu/) generated the first significant samples of the leaf litter invertebrate fauna of Mesoamerica (including southern Mexico). This project focused on sampling ants and weevils from the litter layer of the tropical forest floor, but it also sampled many different non-target taxa, including many litter anillines. By 2012, the second author (DHK) had assembled on loan most available material representing Mesoamerican Anillina at the California Academy of Sciences, San Francisco. Several hundred specimens of the subtribe were borrowed from the collections of the six institutions noted below. This material served as the basis of and inspiration for the current report. In this paper, we present the results of a taxonomic study of one intrageneric group of species of Geocharidius, the integripennis species group.

Materials and methods

This study is based on examination of 455 specimens belonging to the integripennis group of species of Geocharidius, which includes 15 species. Material was borrowed from and/or is deposited in the following institutions, identified in the text by the following associated codens:

CAS California Academy of Sciences, 55 Music Concourse Drive, San Francisco, California 94118 (D. H. Kavanaugh, Curator)

CMNC Canadian Museum of Nature, Entomology, P.O. Box 3443, Station D, Ottawa, Ontario, Canada, K1P 6P4 (R. S. Anderson, Curator)

CMNH Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, U.S.A. 15213 (R. L. Davidson, Collections Manager)

KUNHM University of Kansas Natural History Museum, 1345 Jayhawk Blvd., Lawrence, Kansas, 66045-7593USA (Z. Falin, Collection Manager)

MNHN Muséum national d’Histoire naturelle de Paris, 57 Rue Cuvier, Paris, 75005, France (T. Deuve and A. Taghavian)

NMNH Department of Entomology, United States National Museum of Natural History, Smithsonian Institution, Washington, D. C., U.S.A. 20013-7012 (T. L. Erwin, Curator)

Verbatim label data are given for type specimens of all newly described taxa, with label breaks indicated by a slash (“\”). For a series of KUNHM specimens with the same geographical labels but differing in various barcode numbers only, these numbers were replaced in the text by periods of ellipsis (“…”).

Measurements. All specimens were measured electronically using a Leica M420 macroscope equipped with a Syncroscopy AutoMontage photomicroscopy system (SYNCROSCOPY, Synoptics Ltd.). Measurements for various body parts are encoded as follows: LH = length of head, measured along midline from anterior margin of labrum to a virtual line connecting posterior supraorbital setae; WH = width of head, at level of anterior supraorbital setae; WPm = maximum width across pronotum; WPa = width across anterior angles of pronotum; WPp = width across posterior angles of pronotum; LP = length of pronotum from base to apex along midline; WE = width of elytra, at level of 4^th umbilicate setae; LE = length of the elytra, from apex of scutellum to apex of left elytron; SBL = standardized body length, a sum of LH, LP and LE. Measurements of SBL are given in millimeters; others are presented as eight ratios: mean widths-WH/WPm and WPm/WE and body parts-WPa/WPp, WPm/WPp, WPm/LP, WE/LE, LE/SBL and WE/SBL. All values are given as mean ± standard deviation.

Illustrations. Digital photographs of the dorsal habitus of new species were taken with the AutoMontage system using a Leica M420 macroscope. Line drawings of selected body parts were made using grids on a Labomed Lx400 compound microscope. Scanning electron micrographs were made with coating on a LEO 1450VP SEM. Diagrams were prepared using Statistica 6.0. (StatSoft Inc.).

Dissections. Dissections were made using standard techniques. Genitalia were dissected from abdomens of specimens previously softened in boiling water for 20–30 minutes. Contents of the abdomen were cleared using boiling 10% KOH for 2-3 minutes to remove internal tissues, and then washed in hot water before examination. After examination, genitalia were mounted on plastic transparent boards in dimethylhydantoin formaldehyde resin (DMHF) and pinned beneath the specimen. In some species, investigation of body parts was undertaken in the following way. The whole specimen was cleared using boiling 10% KOH for ~5 minutes, then washed and dissected. Disassembled body parts from a single specimen were placed on plastic transparent cardboard, properly oriented, mounted in DMHF and pinned together with the specimen labels.

Type material. The authors had no opportunity to investigate type material of the Mexican species of Anillina described by A. Vigna Taglianti. The identification of Geocharidius zullinii was made only on the basis of the original description of the species (Vigna Taglianti 1973). Types of the Guatemalan species of Geocharidius described by T. L. Erwin in his revision of Central American Bembidiini (Erwin 1982) were examined. All paratypes listed in the treatments for new species have been labeled with appropriate yellow paratypes labels, which have not been included in the verbatim label data provided for each specimen.

Terms. Terms used in the paper are largely of general use and follow the literature (Ball and Bousquet 2000; Ball and Shpeley 2005, 2009; Erwin 1974; Jeannel 1963), except those for ventral surface structures, terms for which follow the Handbook of Zoology (Lawrence et al. 2010). We use the term “dorsal sclerites” (eg. Fig. 9A, D, E and H) to refer to a complex of more or less sclerotized figs and/or flagellum-like pieces in the dorsobasal region of the retracted internal sac of the male median lobe. These sclerotized elements are highly varied in their size, shape and number and/or degree of fusion among males of different species of this species group, and we have not yet distinguished individual homologies among the varied elements. However, we distinguish this complex of sclerites as a group from the “ventral sclerites” complex found in males of many species of Anillinus Casey (1918) along with the dorsal sclerite complex (eg., see Sokolov 2014, fig. 6K, vsc). We defined Nuclear Central America as the region between the Isthmus of Tehuantepec and the Nicaraguan Depression (Schuchert, 1935).

Species ranking. Species recognition is in accordance with our previous approach (Sokolov et al. 2004), except for cases explained in the text.

Arrangement of taxa in the text. Taxonomic treatments of species are arranged separately by country for the region (i.e. Mexico, Guatemala and Honduras) consistent with the geographical distinctions made in our key to species. For each country, species treatments are arranged in alphabetical order..

Descriptions. The scheme of description generally follows that of Ball and Shpeley (2005, 2009).

Map. The map (Fig. 22) was downloaded from the web-site: http://www.maps-for-free.com/ and adjusted using Adobe Photoshop® software.

Taxonomy

Geocharidius Jeannel

Geocharidius Jeannel, 1963: 107 (type species Anillus integripennis Bates, 1882, by original designation)

Recognition

The members of this genus are distinguished from those of the other North and Central American Anillina by the following combination of characters: frontal area of head with small median tubercle; maxillary palps with palpomere 4 shorter than 1/4 that of palpomere 3; labial ligula without paraglossae, mentum and submentum separated by mental-submental suture; pronotum convex, with short vestiture throughout, including the areas forward of the lateral setae; elytra without fixed discal setae and with the 7^th and the 8^th and the 8^th and the 9^th pores of the umbilicate series separated by equal distances; metendoventrite linear without lateral arms; and intercoxal process between the hind legs widely triangular (Sokolov 2013).

Included taxa

The species of Geocharidius, as treated at present (Lorenz 2005), are arranged in two groups, based on body form: those with a subdepressed form and those with a globose habitus (Erwin 1982). Species with members subdepressed in habitus (Fig. 2A–C) correspond to the type species of the genus and are treated below as the integripennis species group. Members of the genus with a globose habitus (Fig. 2D), like Geocharidius phineus Erwin, Geocharidius romeoi Erwin and similar undescribed species, are not treated in this report.

The integripennis species group

Recognition. Members of this group are distinguished from the other representatives of the genus by the following combination of external characters: head totally covered with microlines, microsculpture mesh pattern isodiametric (Figs 1A–C) and elytra only moderately convex (subdepressed) (Fig. 2A–C). Most species also have members with the elytra totally covered with microlines in form of isodiametric mesh pattern (Figs 1G–H), males with long copulatory sclerites of the internal sac (Figs 9, 13, 19) and females with simple, not bilobate, spermatheca (Figs 11, 17, 21).

Description.Size. SBL range 1.15-1.61 mm.

Habitus. Body form slightly to moderately convex, subparallel or slightly ovoid.

Color. Body monocolorous, brunneorufous or rufotestaceous, appendages testaceous.

Microsculpture. Dorsal surface with polygonal sculpticells present on head in all species, also on elytra except in G. andersoni members with smooth elytra (Fig. 1I). Development of microsculpture on pronotum and proepisternum (pes) varied among different species (Figs 1D–F, Figs 3A–C).

Luster. Body surface shiny.

Macrosculpture. Body surface sparsely and finely punctate.

Vestiture. Body surface covered with sparse yellow setae of moderate and more or less equal length throughout.

Fixed setae. Primary head setae include one pair of clypeal, one pair of frontal and two pairs of supraorbital setae. Mentum (Fig. 5) with two pairs of long primary (paramedial [pms] and lateral [lms]) setae. Submentum (Fig. 5) with three groups of setae: two (Fig. 5D) to three (Fig. 5C) in medial row (mss), two (Fig. 5F) to three (Fig. 5C) in lateral rows (lss) and one pair of primary basal setae (prss). Elytra without discal setae (Fig. 2), but with scutellar (ed2) and apical setae (ed8) present. Last three (7^th, 8^th and 9^th) pores of umbilicate series (eo7, eo8 and eo9) in line and equally spread apart (Fig. 2B). Fifth abdominal ventrite (Fig. 3G–I) of male with one pair (Fig. 3H) and of female with two pairs (Fig. 3I) of abdominal setae along the posterior margin.

Head (Fig. 1A–C). Anterior margin of clypeus straight. Frontal area with small tubercle medially near frontoclypeal suture. Fronto-lateral carinae distinct and long.

Eyes. Absent.

Antennae. Submoniliform, with 11antennomeres, extended to about posterior margin of pronotum. Antennomeres 1 and 2 elongate, of approximately equal length and 1.4-1.5 times longer than antennomere 3, which is only slightly elongate and 1.1-1.2 times longer than antennomere 4. Antennomere 4 the shortest and 1.1.-1.2 times shorter than antennomere 5. Antennomeres 5 to 10 globose, antennomere 11 conical and 1.6-1.7 times longer than antennomere 10.

Labrum (Fig. 1A–C). Transverse with straight, entire anterior margin, with six setae apically, increasing in size from central pair outward.

Mandibles (Fig. 4). Right mandible with distinct anterior (art) and posterior (prt) retinacular, terebral (tt), and molar (mt) teeth. Left mandible with terebral and molar teeth only. Premolar teeth absent from both mandibles.

Maxillae. Cardo trianguloid, stipes with dorsal and ventral lobes, galea dimerous, lacinia standard for bembidiines. Palpus (Fig. 1A–B) with short 4^th palpomere, 0.2–0.25 length of palpomere 3.

Labium (Fig. 5). Mental tooth present; mentum (m) and submentum (sm) divided by mental-submental suture. Glossal sclerite (gsc) bisetose, without distinct paraglossae.

Prothorax. Pronotum cordiform, of moderate length (LP/SBL varied from 0.23 to 0.24 among species, LP/LE varied from 0.38 to 0.42 among species), moderately convex, not sinuate posteriorly. Basal margin of pronotum with slightly protruding medial portion. Anterior angles indistinct, broadly rounded. Posterior angles denticulate, with two or three small denticles anterior to angles. Prosternum (Fig. 3A–C, ps) slightly protruding at the anterior margin medially, there with a group of longer setae relative to other prosternal vestiture, also with a pair of long ambulatory sensor setae (pas) at the middle of sclerite. Prosternal intercoxal process unmargined, slightly dilated apically and obtusely truncate at apex, with a row of sparse setulae along midline.

Scutellum. Externally visible, triangular, with rounded apex.

Elytra. Moderate in length (LE/SBL varied from 0.57 to 0.60 among species), without visible interneurs. Basal margination varied (long in some species, extended halfway between humeral angle and scutellar pore (Fig. 1H–I, bm), very short in others, length about equal to diameter of basal setiferous pore socket (Fig. 1G)) but distinct in all species. Lateral elytral margin without subapical sinuation in apical half.

Hind wings. Absent.

Pterothoracic venter (Fig. 3D–F). Metaventrite (mtv) short, distance between meso-and metacoxae (mtcx) slightly less than the diameter of mesocoxa (mscx). Metanepisternum short, subquadrate, with anterior and outer margins of equal length. Metendoventrite linear without lateral arms.

Legs. Moderate in length, not elongate. Prothoracic legs of males with 1^st protarsomere not dilated, but with varied setal pattern. In some species (Fig. 6A) tarsomeres 1-4 of males with one to three pairs of slightly dilated adhesive setae (Stork 1980), which are absent from protarsi of females (Fig. 6B); in males of other species, these setae on tarsomeres 2-4 only (Fig. 6C); and in other species, males have adhesive vestiture similar to females (Fig. 6D–E). Protibiae (Fig. 6F–I) with antenna cleaner of type B (Hlavac 1971), with both anterior (asr) and posterior (psr) apical setal rows and concave apico-lateral notch (tbn). Profemora moderately swollen. Mesotibiae (Fig. 7A–D) with two terminal spurs (mss), tibial brush (msb) and a row of modified setae posteriolaterally (msms). Metafemora unmodified, metatibiae (Fig. 7E–H) with two terminal spurs (mts), tibial brush (mtb) and one modified seta (mtms) in posteriolateral setal row. Tarsi pentamerous, last and 1^st tarsomeres are the longest, 2-4 tarsomeres of equal length on the tarsi of all legs, 1^st tarsomere shorter than combined length of 2-4 tarsomeres. Tarsal claws simple, untoothed.

Abdominal ventrites. Five visible abdominal ventrites: 2^nd ventrite longest, more than 3 times longer than 3^rd or 4^th, 3^rd and 4^th equal in length; the last, 5^th, approximately 1.5 times longer than 4^th. Intercoxal process (ipa) of 2^nd ventrite broad (Fig. 3D–F), widely triangular.

Male genitalia. Median lobe of aedeagus anopic, elongate, arcuate and twisted. Internal sac with dorsal copulatory sclerites only, which are long, longer than half of length of the median lobe, except in G. comayaguanus male in which they are rather short (Fig. 19K–L, O–P). Sclerites in form of a long fig, rounded or pointed at basal end, and typically tapered into a long flagellum in apical half, in a few species tapered as a short blade-like structure. Additional spines of internal sac absent. Parameres bisetose. Left paramere large and relatively narrow, mostly with long and narrow apical constriction. Right paramere small and narrow. Ring sclerite (Figs 10, 16, 20) ovate or triangular-ovate with an elongate handle-like extension of varied shape.

Ovipositor. Gonocoxite 1 asetose. Gonocoxite 2 triangular, 1.8–2.0 times longer than its basal width, slightly to moderately curved, with lateral and medial ensiform and two apical nematiform setae. Ensiform setae of similar length and shape. Laterotergite with 5-7 setae.

Female internal genitalia. Spermatheca simple (Figs 11, 17, 21), not bilobate, either unsclerotized fusiform or sclerotized of varied shape, typically fusiform with a bulb-like enlargement apically, straight or bent rectangularly. Parts of spermatheca mostly undifferentiated and named in relation to point of attachment of the spermatecal gland: cornu from point of gland attachment to the apex, and nodulus from point of gland attachment to point of duct attachment (Fig. 11). The ramus, the protruding area of attachment of the spermathecal gland (Maddison 1993), is flat and not developed in the species under consideration here.

Included taxa. The integripennis species group includes three previously described species: G. integripennis (Bates), G. zullinii Vigna Taglianti, G. gimlii Erwin, and twelve new species, described below: G. andersoni, sp. n., G. vignatagliantii, sp. n., G. erwini, sp. n., G. minimus, sp. n., G. jalapensis, sp. n., G. balini, sp. n., G. longinoi, sp. n., G. antigua, sp. n., G. lencanus, sp. n., G. celaquensis, sp. n., G. comayaguanus, sp. n. and G. disjunctus, sp. n.

Geographical distribution. The species of this group now are known from mountain ranges of southern Mexico (state of Chiapas), Guatemala and Honduras (Fig. 22).

Way of life. According to label information, specimens of this group were collected from leaf litter within the 2050–2950 m elevation range in the mountains of southern Mexico, within the 1600–3200 m range in the mountains of Guatemala, and within the 1300–2500 m range in the mountains of Honduras. Beetles were extracted from litter in oak, pine, pine-oak, mixed hardwood (without oaks), cloud and lower and upper montane forests. Months of collection include May through September and November.

Relationships. The position of the integripennis group species within the genus is unclear at present and awaits further morphological study of the globose representatives of Geocharidius and a molecular phylogenetic analysis of all species.

Figures 1.

SEM illustrations of structural features of body parts of Geocharidius species. A–C head, dorsal aspect: A G. balini B G. zullinii CG. andersoni.D–F right half of pronotum, dorsal aspect: D G. balini E G. zullinii F G. andersoni. G–I basal part of right elytron: G G. balini H G. zullinii I G. andersoni Legend: bm – basal margin; cl – clypeus; ft – frontal tubercle; lb – labrum; mp3 – maxillary palpomere 3; mp4 – maxillary palpomere 4. Scale = 0.05mm.

Figures 2.

SEM illustrations of structural features and shape of elytra of Geocharidius species, left lateral aspect. A G. erwini B G. jalapensis C G. comayaguanus D G. phineus. Legend: ed2 – scutellar seta; ed8 – apical seta; eo1-9 – setae 1-9 from the umbilicate series. Scale = 0.2mm.

Figures 3.

SEM illustrations of structural features of body parts of Geocharidius species. A–C prothorax, ventral aspect: A G. zullinii B G. erwini C G. comayaguanus. D–F pterothorax, ventral aspect: D G. jalapensis E G. minimus F G. comayaguanus. G–I abdominal ventrites 3-5: G G. minimus, male H G. jalapensis, male I G. jalapensis female. Legend: asts – abdominal sternal terminal seta; ipa –intercoxal process of abdominal ventrite 2; mscx – mesocoxa; msp – mesosternal process; mtcx – metacoxa; mtp – metasternal process; mtv – metaventrite; pas – prosternal ambulatory seta; pep – proepipleuron; pes – proepisternum; prcx – procoxa; ps – prosternum; psp – prosternal process; v3-v5 – abdominal ventrites 3-5. Scale = 0.05mm.

Figures 4.

SEM illustrations of structural features of mandibles of Geocharidius species. A–B G. zullinii: dorsal aspect of left and right mandibles, respectively C–D G. jalapensis: dorsal aspect of left and right mandibles, respectively E–F G. zullinii:–ventral aspect of left and right mandibles, respectively G–H G. jalapensis: ventral aspect of left and right mandibles, respectively (right mandible with Λ-shaped crack apically from retinacular ridge). Legend: art – anterior retinacular tooth; bemr – molar ridge, basal extension; it – incisor tooth; mr – molar ridge; mt – molar tooth; pog – posterior occlusal grove; prt – posterior retinacular tooth; rr – retinacular ridge; tr – terebral ridge; tt – terebral tooth; vg – ventral groove; vm – microtrichia. Scale = 0.05mm.

Figures 5.

SEM illustrations of structural features of labial complex of Geocharidius species. A G. erwini B G. balini C G. lencanus D G. zullinii E G. longinoi F G. minimus. Legend: gsc – glossal sclerite; lms – lateral mental seta; lss – lateral submental seta; m – mentum; mss – medial submental seta; pms – paramedial mental seta; prss – primary basal submental seta; sm – submentum. Scale = 0.05mm.

Figures 6.

SEM illustrations of structural features of front legs of Geocharidius species. A–E protarsi, ventral aspect: A right protarsus of G. jalapensis, male B left protarsus of G. jalapensis, female C right protarsus of G. erwini, male D right protarsus of G. minimus, female E left protarsus of G. minimus, male F–I protibia: F right protibia of G. andersoni, dorso-lateral aspect G left protibia of G. lencanus, lateral aspect H left protibia of G. comayaguanus, ventral aspect I right protibia of G. erwini, ventral aspect. Legend: ac – antenna cleaner; as – adhesive seta; asp – anterior spur; asr – anterior setal row; cls – clip seta; psp – posterior spur; psr – posterior setal row; sb – setal band; ta1-ta4 – tarsomeres 1-4. Scale = 0.05mm.

Figures 7.

SEM illustrations of structural features of meso- and metatibia of Geocharidius species, various aspects. A–D mesotibia: A right mesotibia of G. jalapensis, ventral aspect B left mesotibia of G. minimus, medial aspect C left mesotibia of G. longinoi, ventral aspect D left mesotibia of G. comayaguanus, medial aspect E–H metatibia: E right metatibia of G. zullinii, medial aspect F left metatibia of G. balini, medial aspect G left metatibia of G. longinoi, ventral aspect H right metatibia of G. comayaguanus, ventral aspect. Legend: msb – mesotibial brush; msms – mesotibial modified seta; mss – mesotibial spur; msta1 – mesotarsus 1; mtb – metatibial brush; mtms – metatibial modified seta; mts – metatibial spur; mtta1 – metatarsus 1. Scale = 0.02mm.

A key for identification of adults of the integripennis species group of Geocharidius Jeannel

The following key includes all known members of the integripennis species group. The key makes use of distributional information because each of the three countries mentioned has its own Geocharidius assemblage, the ranges of which are non-overlapping with those of neighboring countries. Our current information on species distributions may prove to be incomplete with additional sampling, so dissection and examination of genitalia should be used for confirmation wherever possible.

1	Body form slightly to moderately convex (Fig. 2A–C) and EITHER with head (Fig. 1A–C) and elytra (Fig. 1G–H) totally covered with microsculpture throughout OR, if only head covered with microsculpture, then elytra subparallel with prominent rounded humeri (Fig. 8C)	2
–	Body forms globose, with markedly convex elytra (Fig. 2D) and EITHER frontal area of head without microsculpture OR, if frontal area with microsculpture, then elytra ovoid with widely rounded humeri (Fig. 78, p. 76, Sokolov 2013)	other groups of Geocharidius
2	Specimen from Mexico	3
–	Specimen from Guatemala	5
–	Specimen from Honduras	12
3	Specimen larger (SBL range 1.40–1.61 mm). Habitus as in Fig. 8C. Elytra almost subparallel in basal two-thirds with rectangularly rounded humeri. Microsculpture developed only on head; pronotum and elytra smooth, without evident microscuplture	G. andersoni sp. n.
–	Specimen smaller (SBL range 1.18–1.40 mm). Habitus as in Fig. 8A–B. Elytra subparallel only in middle part, humeri broadly rounded. Microsculpture present on head and elytra, only pronotum smooth	4
4	Specimen from the Chiapas Highlands. Male with shaft of median lobe of male aedeagus (Fig. 9A, D) widened apically and with dorsal sclerites of internal sac compact. Female with spermatheca unsclerotized, long and fusiform (Fig. 11A)	G. zullinii Vigna Taglianti
–	Specimen from the Sierra Madre de Chiapas. Male with shaft of median lobe of aedeagus (Fig. 9E) subparallel and with dorsal sclerites of internal sac partitioned. Female with spermatheca sclerotized, short and bean-like (Fig. 11B)	G. vignatagliantii sp. n.
5	Elongate (Fig. 12H), smaller on average (SBL range 1.11–1.24 mm). Pronotum with basal margin narrower (WPa/WPp 1.06±0.024). Pronotum and proepisternum smooth. Male with dorsal sclerites of internal sac in form of a flagellum with basal part slightly widened and bent laterally (Fig. 13G, H). Female with spermatheca as in Fig. 17C	G. minimus sp. n.
–	Elongate ovoid (Fig. 12A–G), larger on average (SBL range 1.16–1.57 mm). Pronotum with basal margin wider (WPa/WPp<1.03). If pronotum smooth, then proepisternum with microsculpture. If male with dorsal sclerites of internal sac formed as a long flagellum (Fig. 19A–B), then their base not bent laterally. Spermatheca of female, if fusiform, then with distinct apical bulb-like enlargement (Fig. 17B, D, E)	6
6	Pronotum wider basally, width between posterior angles greater than between anterior angles (Wm/Wp<0.97)	7
–	Pronotum with narrower basal margin, width between posterior angles equal to that of anterior angles (0.97<Wm/Wp<1.03)	8
7	Specimen smaller (SBL range 1.26–1.29 mm). Habitus as in Fig. 12G. Male with dorsal sclerites of internal sac formed as a flagellum-like structure apically, abruptly and markedly widened towards rounded basal part (Fig. 19A–B). Female with spermatheca short (Fig. 21A), with swollen nodulus. Specimen from the volcanic chain of the Guatemalan Cordillera	G. antigua sp. n.
–	Specimen larger (SBL range 1.34–1.51 mm). Habitus as in Fig. 12C. Male with dorsal sclerites of internal sac formed as a wavy, ribbon-like structure (Fig. 13R), of approximately equal width along its entire length. Female with spermatheca elongate, of similar breadth along entire length (Fig. 17F). Specimen from the interior: the Sierra de las Minas range	G. longinoi sp. n.
8	Pronotum smooth (as in Fig. 1E). Male with dorsal sclerites of internal sac markedly extended basally through basal orifice (Fig. 13A, D) as a long and narrow fig, widened and rounded basally. Female with spermatheca, if fusiform, then also curved (Fig. 17B)	9
–	Pronotum covered with microsculpture (Fig. 1D). Male with dorsal sclerites of internal sac slightly extended basally through basal orifice, EITHER elongate and pointed basally (Figs 13K–L) OR formed as a wide fig (Fig. 13O). Female with spermatheca fusiform and straight, not bent (Fig. 17D–E)	11
9.	Specimen smaller on average (SBL range 1.16–1.31 mm). Habitus as in Fig. 12E. Male with dorsal sclerites of internal sac gradually dilated basally to straight basal part (Fig. 13D). Spermatheca of female fusiform (Fig. 13B)	G. erwini sp. n.
–	Specimen larger on average (SBL range 1.33–1.43 mm). Habitus as in Fig. 12A–B. Male with dorsal sclerites of internal sac abruptly dilated basally with enlargement curved ventrally (Figs 13A, 15). Female with spermatheca bean-shaped (Fig. 17A)	10
10.	Body form broad, ovoid (Fig. 12A). Pronotum markedly transverse (Wm/Le=1.32) and distinctly constricted posteriorly (Wm/Wp= 1.38). Specimen from the Sierra de los Cuchumatanes (Huehuetenango Department)	G. gimlii Erwin
–	Body form narrow, elongate ovoid (Fig. 12B). Pronotum less transverse (Wm/Le=1.25±0.009) and less constricted toward base (Wm/Wp= 1.33±0.002). Specimen from the Cerro Maria Tecún (Totonicapán Department)	G. integripennis (Bates)
11.	Specimen smaller on average (SBL range 1.22–1.34 mm). Habitus as in Fig. 12F. Male with dorsal sclerites of internal sac formed as a wide fig widened basally (Fig. 13O). Female with spermathecal gland short (Fig. 17E)	G. balini, sp. n.
–	Specimen larger on average (SBL range 1.33–1.57 mm). Habitus as in Fig. 12D. Male with dorsal sclerites of internal sac formed as an elongate fig, tapered and pointed basally (Figs 13K–L). Female with spermathecal gland long, longer than spermatheca (Fig. 17D)	G. jalapensis sp. n.
12.	Pronotum and proepisternum covered with microsculpture. Male with dorsal sclerites of internal sac long, only slightly widened basally (Fig. 19E, H). Female with spermatheca slightly dilated in apical fourth and with point of spermathecal gland attachment closer to the apex (Fig. 21B–C)	13
–	Pronotum and proepisternum smooth, without evident microsculpture. Male with dorsal sclerites of internal sac EITHER short (Fig. 19K–L, O–P) OR, if long, then these abruptly and markedly dilated basally (Fig. 19Q, T). Female with point of spermathecal gland attachment to spermatheca closer to the basal end and EITHER tapered apically OR of similar breadth over apical half (Fig. 21D–E)	14
13.	Specimen larger (SBL range 1.30–1.47 mm). Habitus as in Fig. 18B. Male with apical part of median lobe of aedeagus attenuated (Fig. 19H). Female with spermatheca curved apically (Fig. 21C)	G. lencanus sp. n.
–	Specimen smaller (SBL range 1.15–1.20 mm). Habitus as in Fig. 18A. Male with apical part of median lobe of aedeagus of average shape (Fig. 19E). Female with spermatheca straight (Fig. 21B)	G. celaquensis sp. n.
14.	Male with dorsal sclerites of internal sac short (Figs 19K–L, O–P). Female with spermatheca tapered apically (Fig. 21D)	G. comayaguanus sp. n.
–	Male with dorsal sclerites of internal sac long (Figs 19Q, T). Spermatheca of female of similar breadth throughout apical half (Fig. 21E)	G. disjunctus sp. n.

Species from Mexico

Geocharidius andersoni sp. n.

http://zoobank.org/97465882-51B8-473D-899A-6A0300DDAB82

Figs 1C, F, I, 6F, 8C, 9H–J, 10C, 11C, 22, 23

Type material

HOLOTYPE, a male, in CMNH, point-mounted, dissected, labeled: \ MEXICO: Chiapas, Cerro Huitepec (Pico), ca. 5km W San Cristobal, 2750m, 15 IX 1991, R. Anderson,#91-101, ex: cloud forest litter \ CMNH \ HOLOTYPE Geocharidius andersoni Sokolov and Kavanaugh 2014 [red label] \. PARATYPES: A total of 4 specimens (1 male and 1 female were dissected), deposited in CAS and CMNH, labeled same as holotype except for one female, which has an additional label \ Anillinus sp. det. D. Shpeley 1997 \.

Type locality

Mexico, Chiapas, Chiapas Highlands, Cerro Huitepec.

Etymology

The specific epithet is a Latinized eponym in the genitive case, and is based on the surname of Robert S. Anderson, Curator of Entomology at the Canadian Museum of Nature, Ottawa, Canada, the collector of the type series of this species.