Chrysotus tibetensis, Liu, Ruosi, Wang, Mengqing & Yang, Ding, 2013

Liu, Ruosi, Wang, Mengqing & Yang, Ding, 2013, Chrysotus Meigen (Diptera: Dolichopodidae) from Tibet with descriptions of four new species, Zootaxa 3717 (2), pp. 169-178 : 176-177

5. Chrysotus tibetensis sp. nov.

( Figs 5 , 15–16 )

Diagnosis. First flagellomere subtriangular, 1.4 times wider than long. Legs mostly black, fore and mid tibiae yellow with black base and dark yellow to brown apex, hind tibia entirely black.

Description. Male. Body length 2.1–2.3 mm, wing length 2.0– 2.2 mm.

Head metallic green with pale gray pollinosity; eyes contiguous on face. Hairs and bristles on head black, postocular bristles (including postero-ventral hairs) black. Antenna black; first flagellomere subtriangular, 1.4 times wider than long; arista black, short pubescent ( Fig. 15 ). Proboscis brown with brown hairs; palpus dark brown with brown bristles.

Thorax metallic green with pale gray pollinosity. Hairs and bristles on thorax black; 6 strong dc, 6–7 irregularly paired acr short and hair-like; scutellum with 2 pairs of bristles, basal pair short and hair-like, lateral pair long; proepisternum with 1 long black bristle on lower part and 1 short black bristle on upper part.

Legs black except fore and mid tibiae yellow with black base and dark yellow to brown apex. Hairs and bristles on legs black. Mid and hind coxae each with 1 outer bristle. Hind femur with 2 av apically. Fore tibia with 1 short ad; apically with 3 bristles. Mid tibia with 2 ad and 2 pd; apically with 4 bristles. Hind tibia with 2 ad and 3 pd; apically with 4 bristles. Relative length of tibia and 5 tarsomeres of legs LI: 4.0: 2.0: 1.0: 0.8: 0.5: 0.5; LII: 5.0: 3.0: 1.4: 1.0: 0.7: 0.7; LIII: 6.2: 2.0: 1.5: 1.0: 0.7: 0.7.

Wing hyaline, tinged brown ( Fig. 5 ); veins blackish, R4+5 and M parallel apically; CuAx ratio 0.3. Squama pale with black hairs. Halter pale.

Abdomen metallic green with pale gray pollinosity; hairs and bristles on abdomen black. Male genitalia ( Fig. 16 ): Epandrium with angular projection posteriorly. Lateral epandrial lobe long and wide. Surstylus stout, tapered apically. Cercus short, with moderately long bristles. Apex of phallus with two lateral lobes bluntly round and swollen apically. Postgonite developed, with bent strip-like anterior arm, protruded tongue-shaped posterior arm and very large ax-like anterior process.

Female. Body length 2.3–2.6 mm, wing length 2.2–2.4 mm. Similar to male, but eyes widely separated and hind tibia with 3 ad and 4 pd.

Specimens examined. HOLOTYPE ♂, China, Tibet, Linzhi, Namaicun, 29°73′N, 94°73′E, 3200 m, 2012. VIII.17–19, W.L. Li. PARATYPE: 5♂ 2♀, China, Tibet, Linzhi, Motuo, 80K, 29°33′N, 95°32′E, 1000 m, 2012. VIII.5–10, X.K. Li.

Distribution. China (Tibet).

Etymology. The specific epithet refers to the locality of the holotype Tibet.

Remarks. The new species is similar to Chrysotus biprojicienus Wei & Zhang in epandrium bearing angular projection posteriorly and apex of phallus bearing two lateral lobes bluntly rounded and swollen apically, and both belong to Chrysotus laesus -group sensu Wei & Zhang (2010). But can be separated from the latter by having the long lateral epandrial lobe, and hypandrium far from the distal margin of the lateral epandrial lobe. In C.

biprojicienus , the lateral epandrial lobe is short, and hypandrium is slightly projecting beyond the waved distal margin of the lateral epandrial lobe.

Acknowledgements

We are grateful to Mr. Wenliang Li (Beijing) and Mr. Xuankun Li (Beijing) for collecting specimens. The research was funded by the Ministry of Science and Technology of the People’s Republic of China (2012FY 111100, MOST Grant 2011FY 120200), and the science & technology fund of Beijing Municipal Commission of Education (KZ201210020019). Two anonymous reviewers provided comments on an earlier draft.

Figures

FIGURES 1 – 5. habitus photographs: 1, Chrysotus altavaginas sp. nov. (male), scale bars = 0.5 mm; 2, Chrysotus biprojicienus Wei & Zhang, scale bars = 0.5 mm; 3, Chrysotus motuoensis sp. nov. (male), scale bars = 0.5 mm; 4, Chrysotus namaicunensis sp. nov. (male), scale bars = 0.5 mm; 5, Chrysotus tibetensis sp. nov. (male), scale bars = 0.5 mm.

FIGURES 15 – 16. Chrysotus tibetensis sp. nov. (male): 15, antenna, lateral view, scale bars = 0.1 mm; 16, genitalia, lateral view, scale bars = 0.1 mm.