Trechus tsampa, 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 : 49-50

Trechus tsampa sp. n.

( Figs. 68 , 92 )

Type material: Holotype male, with label data “ TIBET (South Central) 29.VI.07, Dulong, Kurum vall. NW Lhasa, 4900–5150 m, ca. 29°40’31N 90°46’16E ”, “ Namba side valley, ascent south west of Namba ” ( SMNS) . Paratypes: 2 males, 3 females, with same label data as holotype ( CSCHM, SMNS) .

Description: Body length: 3.2–3.4 mm.

Colour: Surface moderately 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 four as well as antennal segments IV–XI on the whole darkened.

Microsculpture: Supraorbital area and disc of pronotum almost smooth, with very faintly engraved almost isodiametric meshes (x100). More deeply engraved meshes on neck, in frontal furrows of head and in basal depression of pronotum. Faintly engraved slightly transverse meshes on disc of elytra (x80).

Head: Rather stout, with eyes small and slightly protruding; temples approximately 2/3 of length of eyes and strongly wrinkled to the neck. Frontal furrows indistinctly 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: Sub-cordate, slightly transverse and strongly contracted towards base; proportions WP/LP = 1.26–1.31, WP/WPB = 1.35–1.37, WP/WH = 1.23–1.25, WE/WP = 1.53–1.55. Surface strongly convex. Sides slightly concave anterad of hind angles; the latter moderately large, slightly or moderately obtuse (100–120°). Marginal gutter narrow, slightly widened anterad of laterobasal depressions. Base straight or slightly convex in middle and more strongly curved anteriorly at outer fifth. Basal depressions smooth.

Elytra: Oval, broadest almost at mid-length, with proportion WE/LE = 1.53–1.55. Surface strongly convex, not flattened on disc. Shoulders rounded but distinct. Striae finely punctate, first stria fully deep impressed, striae II–III deeply impressed on disc but reduced at base and extreme apex, outer striae much shallower, stria VII hardly visible in anterior half but slightly impressed towards apex. Stria VIII faintly impressed from level of the fifth umbilicate pore backwards but deeply impressed at levels of seventh and eighth pores. Recurrent elytral preapical sulcus connected with the end of the seventh stria. Intervals I–III strongly convex. Preapical seta is located close to the second stria and at the beginning of the posterior elytral eighth.

Legs: Stout.

Male genitalia: Aedeagal median lobe short (LE/LA = 4.1), in lateral view moderately curved, its terminal lamella short and slightly bent downwards at tip. Basal bulb average. Internal sac with the more strongly sclerotized portions indistinctly separated into two elongated, thin, longitudinal sheets situated close together below median lobe ostium.

Etymology: The specific name refers to the Tsampa (Tibetan name for barley grain), which is the most important vegetarian food of the Tibetans at high altitudes. The most delicious Tsampa of Southern Central Tibet comes from the Kurum Valley below the locus typicus of the new Trechus species. Noun in apposition.

Identification: This new species is very similar to T. folwarcznyi Deuve, 1997 , but differs in external characters by having shallower impressed elytral striae IV–VII, and more markedly in aedeagal characters by having a smaller and less strongly curved median lobe with its terminal lamella not bent upwards. It differs from T. astrophilus sp. n. and T. lama sp. n. in the forehand by the less rounded elytra, the stouter appendages and the smaller aedeagal median lobe with different internal sac structure. For differentiation from the similar species T. rarus sp. n., T. singularis sp. n., and T. tseringi sp. n. see the text on the latter species, below.

Relationships: Due to remarkable similarities in the structure of the internal sac sclerotisation with T. folwarcznyi Deuve, 1997 , T. rarus sp. n., and T. singularis sp. n., which can be interpreted as synapomorphic, T. tsampa sp. n. and the other species mentioned above seem to form a group of closely related geographic vicariants within the T. antonini group.

Distribution: Fig. 100 . Transhimalaya: Currently only known from the source area of a snow water brook on south side of lower Namba Valley which is the western side valley of the Kurum Valley north west of Lhasa.

Habitat: Higher alpine zone. The specimens were found under big stones on the bottom of a high valley close to a melt water brook at an altitude of 5150 m.

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 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.

FIGURES 87–92. Habitus. Fig. 87, Trechus martinae sp. n., paratype, female. Fig. 88, T. mieheorum sp. n., holotype. Fig. 89, T. solhoeyi sp. n., paratype, male. Fig. 90, T. yeti sp. n., holotype. Fig. 91, T. astrophilus sp. n., paratype, male. Fig. 92, T. tsampa sp. n., holotype.