Trechus wrzecionkoi, Deuve, 1996

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, Zootaxa 2178 (1), pp. 1-72 : 21-22

The Trechus wrzecionkoi group

Diagnosis: Head with frontal furrows deep, +/- strongly curved at middle. Frons and supraorbital areas moderately convex. Temples convex, smooth. Mandibles normal. Pronotum subcordate, with hind angles well produced. Outer fifth of pronotal base slightly curved anteriorly toward hind angles. Pronotal basal transverse depression diffuse limited towards disc; laterobasal foveae broadly developed. Pronotal median line distinct, deeper near base. Pronotal median line distinct, deeper near base. Hind wings reduced to small stubs. Humerus broadly rounded. Each elytron with parascutellar seta, preapical seta and two discal setae on third interval, with anterior discal seta located on stria III at the end of the anterior elytral quarter, and with middle dorsal seta located on stria III somewhat behind elytral middle. Stria VIII faintly impressed behind the level of the fifth umbilicate pore and deeply impressed from level of the seventh umbilicate pore backwards. Recurrent elytral preapical sulcus deeply impressed and directed to the end of the fifth stria. Ventral surface smooth. Legs moderately short with fairly thick femora and rather thin tibia and tarsi; protibiae moderately dilated towards apices and hardly bowed, each without a longitudinal groove on external surface. Two basal protarsi of male dilated, dentoid at the inner apical border. Basal bulb of aedeagal median lobe not bent downwards, seen laterally, and with basal velum poorly developed. Median lobe apex not hooked, with terminal lamella broad and flat, seen dorsally. Internal sac with sclerotized portion moderately large to large. Parameres relatively stout, with left paramere slightly longer than right one, both with four setae at tip.

Remarks: In external characters, species of this group do not show unique differences compared to species from the T. antonini group, the T. chaklaensis group, or the T. solhoeyi group (see below) and compared to many other species from the eastern border of the Plateau. However, the form of the aedeagal median lobe with a straight base in lateral view and a remarkably broad terminal lamella in dorsal view is so striking, that based on these features the T. wrzecionkoi group can be hypothesized as monophyletic. The species T. jadodraconis Deuve, 1995 , T. lijiangensis Belousov & Kabak, 2001 , and T. weixiensis Belousov & Kabak, 2000 from the eastern border of the plateau, which are forming a natural group as well ( Belousov & Kabak, 2001), show a similar conformation of aedeagal characters, however, these species differ more strongly in the following external characters: Habitus more robust and more ovate, base of pronotum emarginate or oblique on sides, elytra deeply striate and distinctly punctured, apical striola short, foretibia grooved on anterior surface. Despite similarities in aedeagal characters, a close relationship between these two species groups is difficult to ascertain. Another natural species group with a similar form of aedeagal median lobe is the sister species pair T. bogdoensis Belousov & Kabak, 2001 , and T. inexspectatus Belousov & Kabak, 2001 from the Tian Shan mountain range (Bogda Shan, Bogdo-Ola Shan) of the Chinese province Xinjiang. Both these species differ from the T. wrzecionkoi group primarily by having pubescent temporae, distinctly grooved foretibiae and more slender parameres of the aedeagal median lobe. Based on these data a convergent development of aedeagal median lobe character may be accepted.

Species included: T. korae sp. n. (South Central Tibet), T. martinae sp. n. ( South Central Tibet) , T. wrzecionkoi Deuve, 1996 ( South Central Tibet) .