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

description: <i>Trechus namtsoensis</i> sp. n. (Figs. 4, 18, 22) <b>Type material:</b> Holotype male, with label data “ TIBET (South Central) S Namtso 4730–5000 m, lake shore and Langma Vall., 12–13.VII.07”, “ 30°14’19,6N 90°51’10,7E to ca. 30°37’39N 90°51’56E ” (SMNS). Paratypes: 50 males, 27 females, with same label data as holotype (BMNH, CGITZ, CKAB, CSCHM, CWR, MNHN, SMNS); 3 males, 3 females, S Namtso, Langma Valley, 5100–5150 m, 30°37’39,1N 90°51’56,5E, 13.VII.07 (CSCHM); 1 male, 1 female, E-Tibet, 75 km E of Nakchu, 5000 m, 4.VII.1997, leg. A. Wrzecionko, with additional determinational label “ Trechus pseudocameroni Th. Deuve det. 1997” (CSCHM). <b>Description:</b> Body length: 3.5–4.1 mm. Colour: Dorsal surface dark brown, moderately shiny. Antennal joints 1–2, palpi, legs, elytral lateral margin and suture light brown. Anterior elytral quarter diffuse bordered lighter brown than posterior parts. Microsculpture: Discs of head and pronotum smooth, with very faintly engraved almost isodiametric meshes (x100). Surface of elytra with moderately engraved transverse meshes in both sexes (x50). Head: Average sized, with eyes relatively large and moderately protruding. Temples approximately 1/3 times of length of eyes and strongly wrinkled to the neck. Frontal furrows deep, flattened at level of hind suborbital seta. Antennae moderately long, four antennomeres extend beyond the pronotal base. Antennomere III distinctly longer than antennomeres II and IV, both the latter are alike in length. Pronotum: Broad and transverse, with sides moderately contracted towards base; proportions WP/LP = 1.38–1.48, WP/WPB = 1.32–1.42, WP/WH = 1.18–1.23, WE/WP = 1.57–1.63. Surface strongly convex, sides evenly rounded and slightly concave bent just anterad of posterior setae. Hind angles small but almost rectangular or slightly obtuse. Marginal gutter narrow, scarcely widened toward base. Basal groove smooth. Elytra: Oval, broadest almost at mid-length; proportion: WE/LE = 1.30–1.44. Surface convex, not flattened on disc. Shoulders distinct but rounded. Striae impunctate, inner two striae deeply impressed overall, outer striae finer, not deepened before apex, striae VII–VIII usually disappeared. Intervals I–IV slightly convex. The preapical seta is located on the prolonged second stria near to the apex at the beginning of the posterior elytral tenth part. Male genitalia: Aedeagal median lobe more slender, LE/LA = 2.34–2.52, evenly curved basally and remarkably elongated towards apex, with terminal lamella slightly curved upwards, seen laterally. Basal bulb average in size with velum large. Apex of longer copulatory piece slightly bent upwards before tip, the latter shortly bent downwards. Parameres slender, each with 5 (seldom the right one with 4) setae at tip (same as in Fig. 17). <b>Etymology:</b> The specific epithet refers to the largest lake on central Tibetan Plateau, the Namtso, which extends below the north slope of Nyainqentanglha Shan, on which the new species occurs (adjective). <b>Identification:</b> Within the fauna of central Tibetan Plateau north of Nyainqentanglha Shan Massif this species is easily to recognize by its aedeagal median lobe with remarkably elongated terminal lamella and by the longer copulatory piece extending needle like toward ostium. It is very similar to the allopatric <i>T. dongulaensis</i> <b>sp. n.</b> from the westernmost Nyainqentanglha Shan Massif, both in external and genital morphological characters, but differs by having two basal antennal segments lightened, pronotal hind angles sharper, aedeagal median lobe more evenly curved on basal half, seen laterally, median lobe terminal lamella longer, and by having the apex of the longer copulatory piece not clubbed. It is also very similar to the allopatric <i>T. thibetanus</i> Jeannel, 1928, from the Tibetan Himalaya, but differs in the same genital morphological characters as mentioned for differentiation with <i>T. dongulaensis</i> <b>sp. n.</b>, and in addition, it differs by having the longer copulatory piece almost straight toward apex and not bilobate at tip, seen laterally. <b>Relationships:</b> Based on the robust and shortened tip of the longer copulatory piece, <i>T. namtsoensis</i> <b>sp. n.</b> together with <i>T. boulbeni</i> Deuve, 1997, <i>T. dongulaensis</i> <b>sp. n.</b> and <i>T. thibetanus</i> Jeannel, 1928 forms a terminal group of Tibetan species within the <i>T. thibetanus</i> group. <b>Distribution and geographical variation:</b> Fig. 98. Eastern parts of the central Tibetan Plateau north of Nyainqentanglha Shan Massif. <b>Habitat:</b> Lower alpine zone; vertical distribution approximately 4700–5100 m.
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 18-19, DOI: 10.11646/zootaxa.2178.1.1, http://zenodo.org/record/5312276
description: {"references": ["Jeannel, R. (1928) Les Trechus (Coleoptera, Carabidae) de l'Everest expedition, 1924, et remarques sur quelques especes de l'Himalaya. The Annals and Magazine of Natural History, tenth series, 1, 283 - 291.", "Deuve, T. (1997) Nouveaux Trechini du Tibet et des regions limitrophes (Coleoptera, Trechidae). Revue Francaise d'Entomologie (Nouvelle serie), 19 (3 - 4), 139 - 154."]}