Trechus tseringi, 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 : 52-53

Trechus tseringi sp. n.

( Figs. 38 , 80 )

Type material: Holotype male, with label data “ TIBET South Centr. 6.VII.07, 120 km W Lhasa, 2 km NE Dongu La pass, 4800–5000 m, ca. 29°45’01N 89°51’11E ” ( BMNH).

Paratypes: 8 males, 3 females, with same label data as holotype ( BMNH, CSCHM) .

Description: Body length: 3.2–3.4 mm.

Colour: Surface shiny, head and elytra dark brown, pronotum dark reddish brown. Basal segment and tip of the third segment of maxillary palpus, basal antennal segments and legs yellowish brown; second segment and base of the third segment of maxillary palpus, distal half of antennal segment III and antennal segments IV–XI on the whole darkened.

Microsculpture: Supraorbital area and disc of pronotum with faintly engraved almost isodiametric meshes (x80). More deeply engraved meshes on neck, in frontal furrows of head and in pronotal basal depression. Slightly engraved slightly transverse meshes on disc of elytra (x60).

Head: Average, with eyes small and slightly protruding; temples approximately 3/4 of length of eyes and strongly wrinkled to the neck. Frontal furrows slightly flattened at level of hind suborbital seta. Antennae stout, 2 antennomeres extend beyond the pronotal base. Antennomere III as long as antennomere II and slightly longer than antennomere IV.

Pronotum: Relatively small, transverse, moderately cordate and strongly contracted towards base; proportions WP/LP = 1.27–1.31, WP/WPB = 1.36–1.43, WP/WH = 1.24–1.28, WE/WP = 1.59–1.68. Surface strongly convex. Sides evenly rounded in anterior 2/3 and slightly concave anterad of hind angles; the latter relatively large, slightly obtuse (100–110°). Marginal gutter narrow, hardly widened anterad of laterobasal depressions. Base weakly convex in middle and more strongly curved anteriorly at outer fifth; basal depressions smooth or with 1–2 longitudinal wrinkles both sides of pronotal middle.

Elytra: Oval, broadest almost at mid-length, with proportion WE/LE = 1.45–1.50. Surface strongly convex, not flattened on disc. Shoulders rounded but distinct. Striae finely or indistinctly punctate, first stria fully deep impressed, striae II–III deeply impressed on disc but flattened at base and extreme apex, outer striae shallower, stria VII very faintly impressed but present. Stria VIII slightly impressed from level of the fifth umbilicate pore backwards and more deeply impressed at levels of seventh and eighth pores. Recurrent elytral preapical sulcus connected with the end of the seventh stria. Intervals I–IV strongly convex. Preapical seta is located in the third intervall distinctly before the end of second stria and at the beginning of the posterior elytral seventh.

Legs: Rather stout.

Male genitalia: Aedeagal median lobe short (LE/LA = 3.30–3.54), in lateral view evenly curved throughout, with terminal lamella short and slightly bent upwards. Basal bulb average. Internal sac with slightly sclerotized longitudinal sheets below median lobe ostium, without distinct copulatory piece.

Etymology: The specific name is dedicated to Tsering Dorge, Tibetan University, Lhasa, for his kind support of my studies on the Plateau. Formed as a noun (name) in the genitive case.

Identification: This new species is very similar to T. folwarcznyi Deuve, 1997 and its close relatives, but differs in external characters by having more rounded sides of elytra, and (with exception of T. singularis sp. n.) in male genitalia characters by lacking more strongly sclerotized portions of aedeagal internal sac. In addition to the elytral and aedeagal characters mentioned above T. tseringi is easily to distinguish from the above newly described T. rarus sp. n. by the more slender head with less engraved micromeshes and with more distinctly reduced and less protruding eyes. In addition to the elytral characters mentioned above T. tseringi sp. n. is easily to distinguish from the above newly described T. singularis sp. n. by the smaller eyes, smaller and less transverse pronotum, thinner femora, and by the more evenly rounded ventral side of aedeagal median lobe.

Relationships: Due to the relatively small pronotum and the more evenly rounded elytral sides T. tseringi sp. n. seems more closely related to both the below described species T. astrophilus sp. n. and T. lama sp. n. However, no evidence could be found using male genitalia characters. Therefore, the relationships of T. tseringi sp. n. within the T. antonini group are currently difficult to determine.

Distribution: Fig. 100 . Transhimalaya approximately 120 km west of Lhasa: Currently only known from the Dongu La pass area.

Habitat: Lower alpine zone; vertical distribution approximately 4800–5000 m. The species was found under stones close to a melt water brook and on the top of a mountain which has an altitude of approximately 5000m.

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 36–38. Head, pronotum. Fig. 36, Trechus rarus sp. n., holotype. Fig. 37, T. singularis sp. n., holotype. Fig. 38, T. tseringi sp. 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.