Trechus aedeagalis, 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 : 29-35

Trechus aedeagalis sp. n.

( Figs. 31 , 49, 50 )

Type material: Holotype male, with label data “ NEPAL, Prov. Karnali 30°00,14’N 81°35,24’E, Chala , Hochtal SW, 4200–4400 m NN, 25.VI.2001 leg. J. Weipert ” ( NME) . Paratypes: 2 males, 4 females, with same label data as holotype ( CSCHM, CWP, NME) ; 1 male, 2 females, Nepal, Karnali Province, Humla District , 20 km NW Simikot, 3 km W Chala, 4100–4300 m, 29°59’77N 81°35’91E, 24.VI.2001, leg. A. Weigel ( CSCHM, CWG) .

Description: Body length: 3.7–4.0 mm.

Colour: Dorsal surface dark brown, moderately shiny, pronotum, elytral sides and first interval in some specimens reddish brown lightened, palpi, two or three basal antennal segments and legs yellowish brown.

Microsculpture: Head and pronotum with faintly engraved slightly transverse meshes on discs and more deeply engraved almost isodiametric meshes in frontal furrows of head and throughout basal depressions of pronotum. Elytra with slightly transverse meshes which are moderately engraved in males and deeply engraved in females.

Head: As described in T. muguensis sp. n.

Pronotum: Moderately broad, subcordate, strongly contracted towards base; proportions: WP/LP = 1.20–1.27, WP/WPB = 1.32–1.37, WP/WH = 1.20–1.24, WE/WP = 1.65–1.69. Surface convex, sides evenly rounded in anterior half, straight behind middle and concave bent in posterior third towards hind angles; the latter well produced, slightly obtuse to almost rectangular. Base slightly convex in middle and more distinctly curved anteriorly at outer fifth. Marginal gutter narrow in anterior pronotal half, slightly widened towards base. Laterobasal depressions somewhat rough due to strongly convex discs of sculpticells of micromeshes, but without additional punctiformous impressions.

Elytra: Proportion WE/LE = 1.41–1.49. Striae impunctate, two or three inner stria slightly streched on elytral disc, absent at base and flattened on apex; fourth stria and sometimes also fifth stria only suggested as fine incomplete lines; outer striae completely reduced. Preapical seta of second stria is located at the beginning of the posterior elytral eighth. All other elytral characters completely agree with T. muguensis sp. n.

Male genitalia: Aedeagal median lobe with a length of 1.5–1.6 mm, remarkably long (about 40% of total body length! LE/LA = 1.49–1.55), in lateral view strongly curved behind basal bulb, slightly widened in middle, and with undulate curve at apex. In dorsal view median lobe slender, slightly bent behind middle and slightly widened towards apex; tip of terminal lamella truncate or rounded. Internal sac with sclerotized portion relatively long, saccate in lateral view and fishnet-like formed in dorsal view. Both the parameres elongated.

Etymology: The specific epithet is used as an adjective (variable), in allusion to the exceptional aedeagal size of the new species.

Identification: In external characters very similar to T. franzianus Mateu & Deuve, 1979 , and the previously described T. eremita sp. n. and T. muguensis sp. n., but pronotal base more strongly convex. Females with meshes of elytral microsculpture not squamously accentuated as in T. franzianus “forma surdipennis” and in T. sculptipennis sp. n. In addition, T. aedeagalis sp. n. differs from all other species of the T. franzianus group by the shape of its aedeagus, especially by the exceptional long median lobe and the elongated parameres.

Relationships: See remarks in chapter Relationships of T. tilitshoensis Schmidt, 1994 .

Distribution: Fig. 98 . Northeast slope of Saipal Himal, Far Western Nepal Himalaya . Up to now only known from a southern side valley of the river Humla Karnali SW of Chala.

Habitat: Edaphic species of the lower alpine zone; vertical distribution approximately 4100–4400 m.

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 28–35. Head, pronotum. Fig. 28, Trechus pumoensis Deuve, 1997, paratype, male. Fig. 29, T. eremita sp. n., paratype, female. Fig. 30, T. tilitshoensis Schmidt, 1994, paratype, male. Fig. 31, T. aedeagalis sp. n., paratype, male. Fig. 32, T. antonini Deuve, 1997, non-type female specimen from Lhachen La. Fig. 33, T. yeti sp. n., paratype, male. Fig. 34, T. cf. damchungensis Deuve, 1997, paratype, male from Tangula Pass. Fig. 35, T. hodeberti Deuve, 1997, non-type female specimen from Lhachen La.

FIGURES 39–51. Aedeagal median lobe with sclerotized portions of internal sac in lateral view (Figs. 39, 40, 42, 43, 45, 47, 49; Figs. 39, 40, 47, 49 in addition with parameres) and in dorsal view (Figs. 41, 44, 46, 48, 50). Fig. 39, Trechus pumoensis Deuve, 1997, paratype. Figs. 40, 41, T. franzianus Mateu & Deuve, 1979, non-type specimen from Dhauli Lake. Fig. 42, T. tilitshoensis Schmidt, 1994, non-type specimen from Gungdang N-slope. Fig. 43, 44, T. muguensis sp. n., paratype (43) and holotype (44). Figs. 45, 46, T. eremita sp. n., paratype. Figs. 47, 48, T. sculptipennis sp. n., paratype. Figs. 49, 50, T. aedeagalis sp. n., paratype. Fig. 51, T. stratiotes sp. n., paratype.