Trechus yak shogulaensis, Schmidt, 2009

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 : 48-49

Trechus yak shogulaensis ssp. n.

( Figs. 9 , 75 )

Type material: Holotype male, with label data “ TIBET South Centr. 3–4.VII.07, NE of Shogu La pass 5000–5350 m 29°54’48– 29°57’20N 90°08’28– 90°07’49E ” ( BMNH).

Paratypes: 54 males, 17 females, with same label data as holotype ( BMNH, CKAB, CSCHM, CWR, MNHN, SMNS) .

Description: Body length: 3.4–4.0 mm.

Colour, microsculpture and head structure: As described in the nominotypical form.

Pronotum: On an average more transverse and more strongly contracted towards base; proportions: WP/ LP = 1.25–1.34, WP/WPB = 1.31–1.35, WP/WH = 1.19–1.25, WE/WP = 1.55–1.66. Sides evenly rounded in anterior 3/4 and slightly concave just anterad of hind angles; the latter obtuse, not bent outwards. In all other pronotal characters agreeing with the nominotypical form.

Elytra: Proportion WE/LE = 1.55–1.60. Stria VIII more deeply impressed from level of the fifth umbilicate pore backwards. In all other elytral characters agreeing with the nominotypical form.

Male genitalia: LE/LA = 3.16–3.21. Copulatory piece, in dorsal view, more slender and more deeply constricted anterad of base.

Etymology: The subspecific name is derived from the Shogu La pass which is a pass of local importance and which is close to the type locality (adjective).

Identification: This subspecies differs from the nominotypical form by having more obtuse hind angles of pronotum which are not protruding laterally, and by the form of the copulatory piece as shown in Fig. 75 compared to Fig. 76 .

Remarks on taxonomy: The morphological differences between individuals from the nominotypical form and those from T. yak shogulaensis ssp. n. are indeed small but always distinct, and concerning the above mentioned pronotal and male genitalia characters no transitions could be found. These facts could also indicate a distinct species, and hence the subspecific status is preliminary. More field work has to be done to search for further populations along the western Nyainqentanglha Shan. If such populations exist morphological and molecular genetic studies would be helpful to find out whether recently isolated populations are temporarily (e.g. during glacial periods) influenced by gene flow or not.

Distribution and geographical variation: Fig. 100 . Currently only known from the uppermost Shogu Tshu Valley of western Nyainqentanglha Shan Massif, east of Jomo Gangtse Peak.

Habitat: Higher alpine zone; vertical distribution approximately 5000–5300 m. The specimens were found under stones on humid, gently inclined slopes in different expositions, often in snow water gorges.

Figures

FIGURE 100. Map of Southern Central Tibet showing distribution of species of the Trechus antonini group (white circles). 1, T. antonini Deuve, 1997. 2, T. religiosus sp. n. 3, T. astrophilus sp. n. 4, T. budhaensis sp. n. 5, T. rarus sp. n. 6, T. yeti sp. n. 7, T. folwarcznyi Deuve, 1997. 8, T. yak yak ssp. n. 9, T. yak shogulaensis ssp. n. 10, T. tseringi sp. n. 11, T. singularis sp. n. 12, T. tsampa sp. n. 13, T. lama sp. n.

FIGURES 2–11. Pronotum. Fig. 2, Trechus thibetanus Jeannel, 1928, Lectotype. Fig. 3, T. dongulaensis sp. n., paratype, male. Fig. 4, T. namtsoensis sp. n., paratype, male. Fig. 5, T. eutrechoides eutrechoides Deuve, 1992, non-type male specimen from Lamna La. Fig. 6, T. glabratus sp. n., paratype, male. Fig. 7, T. korae sp. n., paratype, male. Fig. 8, T. yak yak ssp. n., paratype, male. Fig. 9, T. yak shogulaensis ssp. n., paratype, male. Fig. 10, T. rolwalingensis rolwalingensis ssp. n., paratype, male. Fig. 11, T. rolwalingensis daldunglana ssp. n., paratype, male.

FIGURES 65–80. Aedeagal median lobe with sclerotized portions of internal sac in lateral view (Figs. 65–71, 77–80; Figs. 65, 68–71, 79, 80 in addition with parameres) and in dorsal view (Figs. 72–76). Figs. 65, 74, Trechus astrophilus sp. n., paratype. Fig. 66, T. lama sp. n., paratype. Fig. 67, T. singularis sp. n., holotype. Fig. 68, T. tsampa sp. n., paratype. Figs. 69, 76, T. yak yak ssp. n., paratype. Figs. 70, 73, T. religiosus sp. n., paratype. Figs. 71, 72, T. chaklaensis sp. n., paratype. Fig. 75, T. yak shogulaensis ssp. n., paratype. Fig. 77, T. antonini sp. n., non-type specimen from Lhachen La (= locus typicus). Fig. 78, T. folwarcznyi Deuve, 1997, non-type specimen from Shogu La (= locus typicus). Fig. 79, T. rarus sp. n., holotype. Fig. 80, T. tseringi sp. n., paratype.