Mexyclothorax baehri Guéorguiev, 2013, sp. n.
Creators: name: Guéorguiev, Borislav
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Carabidae
Mexyclothorax
Mexyclothorax baehri

description: Mexyclothorax baehri sp. n.
Habitus: Fig. 2; male genitalia: Figs. 3–6.
Type material. Holotype ♂, well-preserved (no part missing), mounted on card, genitalia dissected and deposited in euparal on separate card pinned below the first card, “ PAPUA NEW GUINEA West Sepik Prov., summit of Mount Capella, 3960 m BSE exp. 1975” [black print on white label] / “H O L O T Y P E Mecyclothorax baehri sp. nov. Guéorguiev des. 2013” [black print on red label] (NMNHS).
Diagnosis. Small, wingless, vaguely two-colored beetle (head and pronotum piceous, elytra testaceus), characterized by round pronotum with sides noticeably concave towards basal angles, base punctate, and posterior lateral pronotal seta present; convex, ovoid and shiny elytra with finely punctate striae and three setiferous punctures in interval 3; tarsomere 4 of all legs with apical setae at least 2x length of tarsomere, ventral surface of all tarsomeres 4 with very long subapical and apical setae, apical setae extended onto distal 1/4 – 1/5 of tarsomere 5.
Description. Habitus. Body size (5.1 mm) large for average Mecyclothorax taxa, with sub-elongate and convex body and sides of pronotum distinctly sinuate in front of right basal angles (Fig. 2). Measurements. BL: 5.1 mm; BW: 2.2 mm. Ratios. PW/HW: 1.33; PW/PL: 1.15; PbW/PaW: 1.06; EW/PW: 1.55; EL/EW: 1.37. Colour. Piceous on head, pronotum, testaceous on basal sixth of elytra and rufous on remaining part of elytra, margins of pronotum and elytra paler. Clypeus piceous, labrum and mandibles testaceus, palpi rufous, antennae reddish, though antenna from 4th antennomere darker. Legs red-yellow. Lower surface dark piceous to black on head and prosternum, testaceous on mouthparts, mesosternum, metasternum, abdominal sterna, and elytral epipleura. Microsculpture. Most surface of head with reduced microreticulation, only posteriorly, before pronotum apical margin with distinct isodiametric mesh; pronotum entirely microsculptured, with narrow transverse microreticulation; elytra entirely microsculptured, with transverse microreticulation on anterior two thirds and somewhat isodiametric microreticulation on posterior third. Lustre. Dorsal and ventral surfaces glossy, though not iridescent. Head. Rather narrow in relation to prothorax, with impunctate surface; eyes moderately large, convex, laterally rather protruded, orbits small, oblique, about 1/4 of eye length; paraorbital sulci moderately deep, surpassing posterior margin of eye; frontal grooves deep, divergent from clypeus to eyes, almost straight, terminated at half distance between supraorbital pores; distance between supraorbital pores smaller than diameter of eye, anterior pore situated at level of second fourth of eye length, posterior one situated at level of posterior margin of eye; apex of clypeus straight, clypeal suture almost vanished; labrum transverse, slightly concave in middle; mandibles moderately elongate, apically suddenly curved; antennae moderately long, terminal segment exceeding posterior border of pronotum. Pronotum. Round, wider than long; widest diameter about middle or slightly before; sides strongly and evenly curved, with clear excision in front of basal angles, marginal bead narrow, little widened towards base; base only slightly wider than apex, both apical margin and basal margin not bordered; apex straight, fore angles not projecting, rounded off; base almost straight, laterally faintly oblique, basal angles right, slightly projecting outside, though with rounded tips; anterior transverse sulcus complete, well impressed, posterior transverse sulcus faint; midline well impressed, anteriorly reaching anterior transverse sulcus, posteriorly somewhat intersecting posterior transverse sulcus; disk smooth, fairly convex; basal part with deep fovea on each side, basal impressions short, semi-linear, centrally rather convex, below level of disk, very coarsely punctate, with 14–16 distinct, irregular punctures on each side; anterior marginal pore situated in second fifth of pronotum, removed from lateral margin with distance one and half or so than diameter of pore, posterior marginal pore present, situated slightly in front of basal angles. Elytra. Short and wide, dorsally markedly convex, widest diameter slightly behind middle; basal margin distinct, slightly sinuate, reaching parascutellar stria; humeri obtusely rounded; lateral margin evenly curved, with moderately wide bead and slight subapical sinuation; elytral internal plica visible in lateral view; striae 1, 8 and 9 equally impressed, linear, continuous from basal margin to apex (stria 9 from point joining stria 8 to apex), stria 2 slightly abbreviated at humerus and distinct to apex, punctate anteriorly, striae 3 and 4 well impressed on middle two thirds of elytron, strongly punctate, interrupted anteriorly and posteriorly, striae 5–7 obsolete, superficially punctate; parascutellar stria distinct; median four intervals moderately convex, lateral intervals plane; three setiferous punctures in middle of interval 3 or near to stria 3; single apical setiferous puncture in stria 3 closer to lateral margin than to suture; umbilicate setiferous series in stria 8 with a row of 11 pores on left elytron and 10 pores on right elytron, both rows slightly interrupted in middle (between pores 7 and 8 on left elytron and pores 6 and 7 on right elytron); hind wings vestigial. Ventral surface (thorax and abdomen). Entirely impunctate. Metepisternum slightly longer than wide. Sternum VII in male bisetose at apical margin, also with a third smaller seta on right side in middle slightly removed from apical margin. Legs. Basal tarsomeres 1–3 of male protarsi expanded and biseriately squamose underneath. Ventral surface of each lobe of tarsomere 4 in fore and middle legs with fan of several long subapical and apical silky setae, as apical setae extended onto distal 1/4 – 1/5 of tarsomere 5; tarsomere 4 in hind legs only with a few setae which extend onto distal one sixth of tarsomere 5. Male genitalia (Figs. 3–6). Median lobe of aedeagus short, stout, curved down towards apex; basal part without distinct bulb; apex straight, wide, laterally compressed, with obtuse, strongly sclerotized tip, a small ostial triangle present on upper margin; ostium deflected to right; internal sac complex, with few folded and moderately sclerotized plates (Fig. 3). Left paramere large, with broadened basal part and very narrow and elongate apex, one short subapical seta and two longer apical setae, as well with single seta on proximal half of apical lower margin (Fig. 4). Right paramere narrower, with elongate apex, bisetose at tip, with about eight short setae situated evenly along distal two thirds of lower margin and single seta on apical fourth of upper margin (Fig. 5). Urite sub-triangular, with asymmetric base and dissimilar at length lateral arms (Fig. 6).
Affinities. According to several external characters and structure of aedeagus, the new species is most closely related to M. sedlaceki Darlington, 1971. However, the former is distinguished from the latter in: 1/ size of body 5.1 mm (vs. 3.4–4.2 mm in M. sedlaceki, cfr. Baehr, 2008: 136–137); 2/ wider, globe-shaped pronotum, PW/PL 1.15 (vs. slightly transverse-rounded pronotum in M. sedlaceki, PW/PL 1.28–1.38 in M. sedlaceki, cfr. Darlington, 1971: 263, Fig. 21; Baehr, 2008: 136–137); 3/ shorter, stouter median lobe of aedeagus, with wider apex and differently shaped sclerites of the internal sac (vs. thinner median lobe, with narrower apex, cfr. Baehr, 2008: 138, Fig. 2). In addition, the latter species occurs farther east (Bismark Range, Mount Wilhelm, 4250 m) of the type locality of the new species.
Distribution. Papua New Guinea, West Sepik (= Sandaun) Province, Star Mountains, summit of Mount Capella, 3960 m. This species is allopatric with all other New Guinea Mecyclothorax species.
Collecting circumstances. According to Dr. Petar Beron, a participant of the British Speleological Expedition to New Guinea in 1975 (BSE), the collector of the holotype and the circumstances about its collecting remain unknown. The only certain fact is that the specimen was collected at the summit of Capella Peak, ca. 3960 m above sea level.
Etymology. The specific epithet is a noun in the genitive case that honors Martin Baehr who has significantly increased the knowledge of the New Guinean Carabidae.
This new species can be easily identified by modifying couplet 4 in the key to New Guinea Mecyclothorax (Baehr 2008)
4 Elytra with 5 discal punctures and setae (Baehr 2008: Fig. 6). Aedeagus unknown. Kubor Range, about 3600 m ............................................................................................... M. kubor Baehr, 2008 - Elytra with 2–3 discal punctures and setae (present work: Fig. 2) Apex of aedeagus with distinct ostial triangle on upper margin (Baehr 2008: Fig. 2; present work: Fig. 3). Massifs situated northeast or farther west of the Kubor Range............ 4' 4a Length 3.4–4.2 mm. Pronotum more transverse (PW/PL 1.28–1.38). Aedeagus relatively longer and narrow (Baehr 2008: Fig. 2). Bismarck Range: Mt. Wilhelm, 3200–4250 m ..................................... M. sedlaceki Darlington, 1971 4b Length about 5 mm. Pronotum globe-shaped (PW/PL 1.15). Aedeagus relatively short and wide (present work: Fig. 3). Star
Mountains: Mt. Capella, ca. 3960 m ........................................................... M. baehri sp. n.
description: Published as part of Guéorguiev, Borislav, 2013, Taxonomic, nomenclatural, and faunistic records for species in tribes Melaenini, Moriomorphini, Pterostichini, Licinini, and Sphodrini (Coleoptera: Carabidae) in Zootaxa 3709 (1), DOI: 10.11646/zootaxa.3709.1.2, http://zenodo.org/record/222914