Trechus dongulaensis, 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 : 19-20

Trechus dongulaensis sp. n.

( Figs. 3 , 17, 21 , 81 )

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 ” ( SMNS) . Paratypes: 70 males, 26 females, with same label data as holotype ( BMNH, CGITZ, CSCHM, CWR, SMNS) ; 49 males, 63 females, W of Shogu La ,

4650–4850 m, 29°15’18N 90°04’06E to 29°48’15N 90°02’21E, 5.VII.07 ( CKAB, CSCHM, MNHN, NMBE) .

Description: Body length: 3.4–3.8 mm.

Colour: Dorsal surface dark brown, moderately shiny. Scapus (seldom pedicellus), palpi, legs, elytral lateral margin and suture light brown. Anterior elytral third diffuse bordered lighter brown than posterior parts.

Microsculpture: As described in T. namtsoensis sp. n.

Head: Eyes slightly protruding, temples approximately 2/5 times of length of eyes, frontal furrows moderately deep, not flattened at level of hind suborbital seta. In all other characters agreeing with T. namtsoensis sp. n.

Pronotum: Proportions: WP/LP = 1.32–1.39, WP/WPB = 1.18–1.24, WP/WH = 1.23–1.30, WE/WP = 1.65–1.70. Sides evenly rounded and straight just anterad of posterior setae. Hind angles very poorly developed, obtuse or almost rounded. In all other pronotal characters agreeing with T. namtsoensis sp. n.

Elytra: Proportion WE/LE = 1.30–1.42. In all other elytral characters agreeing with T. namtsoensis sp. n.

Male genitalia: Aedeagal median lobe more slender, LE/LA = 2.35–2.42, moderately curved basally, somewhat stretched before middle, elongated towards apex, with terminal lamella slightly curved upwards, seen laterally. Basal bulb average in size with velum large. Apex of the longer copulatory piece slightly clubbed. Parameres slender, each with 5 (seldom the right one with 4) setae at tip.

Etymology: The specific epithet refers to the Dongu La pass on whose slopes the new species occurs (adjective).

Identification: T. dongulaensis sp. n. is very similar to both the allopatric species of South Tibet T. namtsoensis sp. n. and T. thibetanus Jeannel, 1928 , in external and genital morphological characters as well, but can be distinguished by the more poorly developed and more obtuse pronotal hind angles and by the apex of the longer copulatory piece of aedeagal internal sac which is not lobed but somewhat clubbed. In addition, the new species is on average smaller than T. namtsoensis sp. n. and the antennae are darker with pedicellus usually dark brown in distal 4/5. The longer copulatory piece of the aedeagal internal sac is straight toward its apex and not bent upwards as in T. thibetanus , seen laterally. The new species is easily to distinguish from the sympatric T. glabratus sp. n. of the same species group by the presence of well developed micromeshes on the elytral surface in both sexes, and by the median lobe with remarkably elongated terminal lamella and large copulatory pieces.

Relationships: See discussion in chapter Relationships of T. namtsoensis sp. n., above.

Distribution and geographical variation: Fig. 98 . Westernmost parts of Nyainqentanglha Shan Massif.

Habitat: Lower alpine zone; vertical distribution approximately 4650–5000 m. The species was frequently found under stones in yak pastures.

Figures

FIGURE 98. Map of central parts of Tibet and the Himalaya showing distribution of species of the Trechus thibetanus group (white circles), of the Trechus pumoensis group (white squares), of the Trechus rolwalingense group (black circles), and of the Trechus stratiotes group (black squares). 1, T. namtsoensis sp. n. 2, T. dongulaensis sp. n. 3, T. thibetanus Jeannel, 1928. 4, T. glabratus sp. n. 5, T. thorongiensis Schmidt, 1994. 6, T. eutrechoides eutrechoides Deuve, 1992. 7, T. eutrechoides mondaensis Deuve, 1997. 8, T. pumoensis Deuve, 1997. 9, T. tilitshoensis Schmidt, 1994. 10, T. franzianus Mateu & Deuve, 1979. 11, T. muguensis sp. n. 12, T. eremita sp. n. 13, T. aedeagalis sp. n. 14, T. sculptipennis sp. n. 15, T. rolwalingense rolwalingense ssp. n. 16, T. rolwalingense daldunglana ssp. n. 17, T. stratiotes stratiotes ssp. n. 18, T. stratiotes malikasthana ssp. 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 12–27. Aedeagal median lobe with sclerotized portions of internal sac in lateral view (Figs. 12–18, 23–26; Figs. 14, 17, 23, 26 in addition with parameres) and in dorsal view (Fig. 27); apical portion of the longer copulatory piece (Figs. 19–22). Fig. 12, Trechus thorongiensis Schmidt, 1994, paratype, the arrow pointed to the prolongated basal portion of the shorter copulatory piece. Fig. 13, T. eutrechoides eutrechoides Deuve, 1992, non-type specimen from Rongshar Valley. Fig. 14, T. eutrechoides mondaensis Deuve, 1997, paratype. Figs. 15, 19, T. thibetanus Jeannel, 1928, holotype. Figs. 16, 20, T. thibetanus Jeannel, 1928, non-type specimen from Kampa La. Figs. 17, 21, T. dongulaensis sp. n., paratype. Figs. 18, 22, T. namtsoensis sp. n., paratype. Fig. 23, T. glabratus sp. n., paratype. Fig. 24, T. wrzecionkoi Deuve, 1996, non-type specimen from Gyama, Chungenpo Chong side valley. Fig. 25, T. korae sp. n., paratype. Figs. 26, 27, T. martinae sp. n., paratype.

FIGURES 81–86. Habitus. Fig. 81, Trechus dongulaensis sp. n., paratype, female. Fig. 82, T. glabratus sp. n., paratype, female. Fig. 83, T. rolwalingensis rolwalingensis ssp. n., holotype. Fig. 84, T. stratiotes stratiotes ssp. n., paratype, male. Fig. 85, T. muguensis sp. n., paratype, female. Fig. 86, T. sculptipennis sp. n., paratype, female.