Trechus glabratus Schmidt 2009, sp. n.
Creators: name: Schmidt, Joachim
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Carabidae
Trechus
Trechus glabratus

description: <i>Trechus glabratus</i> sp. n. (Figs. 6, 23, 82) <b>Type material:</b> Holotype male, with label data “ TIBET South Centr. 6.VII.07, Doru Tshu Vall. SW Dongu La, 4500–4600 m, ca. 29°43’16N 89°47’12E ” (SMNS). Paratypes: 48 males, 41 females, with same label data as holotype (BMNH, CGITZ, CKAB, CSCHM, CWR, MNHN, NMBE, SMNS). 4 males, 2 females, W of Shogu La, 4650–4850 m, 29°15’18N 90°04’06E to 29°48’15N 90°02’21E, 5.VII.07 (CSCHM). <b>Description:</b> Body length: 3.3–3.7 mm. Colour: Dorsal surface shiny dark brown, antennae, palpi, legs, elytral and pronotal lateral margins, scutellar region and elytral suture light brown. Antennae often darkened from joint III or IV toward apex. Microsculpture: Disc of head smooth, with very faintly engraved meshes (x120). Discs of pronotum and elytra polished; pronotal sides and elytral apex with micromeshes visible under high magnification (x150). Head: Average sized, with eyes moderately small and slightly protruding. Temples approximately 2/5 times length of eyes, strongly wrinkled to the neck. Anterior part of frontal furrows deep, posterior part flattened towards hind suborbital seta. Antennae moderately short, three antennomeres extend beyond the pronotal base. Antennomere III distinctly longer than antennomeres II and IV, both the latter are alike in length. Pronotum: Transverse; with sides moderately contracted towards base; proportions: WP/LP = 1.40–1.47, WP/WPB = 1.24–1.27, WP/WH = 1.28–1.32, WE/WP = 1.53–1.57. Surface strongly convex, sides evenly rounded and straight just anterad of posterior setae. Hind angles very poorly developed, obtuse or almost rounded. Marginal gutter narrow throughout. Basal groove smooth. Elytra: Oval, broadest almost at mid-length; proportion: WE/LE = 1.46–1.52. Surface convex, not flattened on disc. Shoulders distinct but rounded. Striae faintly punctate, only first stria moderately deeply impressed overall, second stria moderately impressed but absent at base, outer striae only suggested as rows of very faintly engraved punctures in elytral middle or completely absent. Intervals I–II slightly convex. Preapical seta is located on the prolonged and strongly outwardly bent second stria near to apex at the beginning of the posterior elytral twelfth to fifteens part. Male genitalia: Aedeagal median lobe moderately long (LE/LA = 2.72–2.79), evenly curved in basal 2/3 and straight toward apex, seen laterally. Terminal lamella relatively short, with apex stubby. Basal bulb average in size with velum large. Both the copulatory pieces thin and elongated, needle-like. Parameres moderately slender, each with four setae at tip. <b>Etymology:</b> The species is named for the reduced elytral microsculpture on the body surface, an important diagnostic feature within the <i>T. thibetanus</i> species group (Latin “glabrat-us, -a, -um”: smooth); adjective. <b>Identification:</b> Within the <i>T. thibetanus</i> group this new species is easily to recognize by the reduced elytral microsculpture on the one hand, and by the reduction of both the sclerotized parts of aedeagal internal sac to needle-like sclerites on the other hand. <b>Relationships:</b> Up to now I could not find any synapomorphy with any other taxon of the <i>T. thibetanus</i> species group. Moreover, according to the derived copulatory pieces of aedeagal internal sac this new species seems to be quite isolated within the species group. <b>Distribution and geographical variation:</b> Fig. 98. Westernmost parts of Nyainqentanglha Shan Massif. <b>Habitat:</b> Lower alpine zone; vertical distribution approximately 4500–4900 m. The species was frequently found under stones on yak pastures.
description: Published as part of <i>Schmidt, Joachim, 2009, Taxonomic and biogeographical review of the genus Trechus Clairville, 1806, from the Tibetan Himalaya and the southern central Tibetan Plateau (Coleoptera: Carabidae: Trechini) 2178, pp. 1-72 in Zootaxa 2178 (1)</i> on pages 20-21, DOI: 10.11646/zootaxa.2178.1.1, http://zenodo.org/record/5312276