Chrysotus biprojicienus, Wei, Lianmeng & Zhang, Lili, 2010

Wei, Lianmeng & Zhang, Lili, 2010, A taxonomic study on Chrysotus Meigen (Diptera: Dolichopodidae) from southwest China: descriptions of eleven new species belonging to the redefined C. laesus - group, Zootaxa 2683, pp. 1-22 : 10-12

5. Chrysotus biprojicienus sp. nov.

( Fig. 5 )

Diagnosis. Eyes contiguous on face. Postocular setae black. All coxae blackish, femora blackish, apex of hind tibiae blackish. Squama pale with brown setulae. Halter pale. Male terminalia with both surstylus and hypandrium stout. Postgonite developed, with bent strip-like anterior arm, widened tongue-shaped posterior arm and very large ax-like anterior process. Hypandrium with two lateral lobes and proximal portion seldom with projection.

Description. Male: Body length 1.8-1.9 mm, wing length 1.4–1.8 mm. Head: Metallic green with pale gray pollinosity; eyes contiguous on face. Setulae and setae on head black, postocular setae (including postero-ventral setulae) black. Antenna black; first flagellomere subtriangular, 0.7 times as long as wide; arista black, with short pubescence. Proboscis blackish brown with brown setulae; palpus dark brown with 1 black apical seta. Thorax: Dark metallic green with pale gray pollinosity. Setulae and setae on thorax black; 6 strong dc, 6–7 irregularly paired acr short and setula-like; scutellum with 2 pairs of setae, basal pair short and setula-like; propleuron with 1 black setula and 1 black seta on lower part. Legs: Yellowish brown, all coxae and trochanters blackish; femora blackish; base of tibiae and apex of hind tibia blackish; fore and mid tarsi from tip of tarsomere 1 onwards brownish, hind tarsus brownish. Setulae and setae on legs black. Mid and hind coxae each with 1 outer seta. Hind femur with 2 av apically. Fore tibia with 1 ad, apically with 3 short setae; mid tibia with 2 ad and 2 weak pd, apically with 4 setae; hind tibia with 2 ad and 3 pd, apically with 4 setae. Relative lengths of tibia and 5 tarsomeres of legs LI 40: 20: 10:.8: 4: 4; LII 50: 24: 11:.8: 4: 4; LIII 60: 18: 13: 10: 5:5. Wing: Hyaline, veins brown; R4+5 and M1+2 parallel apically, CuAx ratio 0.28. Squama pale with brown setulae. Halter pale. Abdomen: Dark metallic green with pale gray pollinosity; setulae and setae on abdomen black. Male terminalia ( Fig. 5 A). Epandrium with angular projection posteriorly. Ventral projection of epandrium with somewhat pointed end, slightly projecting beyond level of waved distal margin of lateral epandrial lobe. Lateral epandrial lobe shorter and wider, with flattened and waved distal margin, bearing 2 stronger setae. Surstylus stout, tapered apically. Cercus short, with moderately long setae. Hypandrium stout, with two lateral lobes bluntly round and swollen apically. Proximal portion of hypandrium lacking projection. Postgonite developed, with bent strip-like anterior arm, widened tongue-shaped posterior arm and very large ax-like anterior process. Female: Body length 2.3–2.4 mm, wing length 2.4–2.5 mm. Similar to male except eyes widely separated. Relative lengths of tibia and 5 tarsomeres of legs LI 68: 38: 16: 10: 8: 8; LII 90: 48: 20: 12: 9: 9; LIII 104: 30: 21: 12: 9: 9. Terminalia ( Figs. 5 B-C). Ventral viewed: Tg6–7 with deep inverted U-shaped incisions; Tg8 divided into pair of rod-like sclerites, each with large triangular sclerite on inner margin mesally, weakly sclerotized; Tg9 retrogressive; acanthophorites (Tg10) divided into two sclerites, each with acute projection, dorsal surface with crest of 4 acute spines; posterior margin of St5 with shallow U-shaped incision; St6 rectangular, with length shorter than width, anterior margin with shallow U-shaped incision; St7 rectangular, weakly sclerotized, with length longer than width, anterior margin with shallow inverted U-shaped incisions; St8 divided into pair of rod-like sclerites, connected anteriorly by sclerotized bridge; St10 fine long curved stick-like, setose. In profile: both Tg8 and St8 widely separated from each other basally, former with large triangular sclerite on inner margin mesally remarkably prominent; acanthophorites (Tg10) long strip-like, consisting of two sclerites; St8 with fork-like end; St9 nearly semicircular sclerite; St10 fine long straight stick-like, with setae; cercus longer diamond-like, bare.

Type material. HOLOTYPE ɗ, Guizhou: Shibing, Yuntaishan, 700 m, 27º09’N, 108º6.5’E, 16.IX.1993, LM Wei and X Zhang. PARATYPES: 5 ɗ, 2 Ψ, same as holotype.

Etymology. From the Latin bi “two, double” and projicien “extrude, stand out”, meaning the sheath of the phallus with a pair of lateral projections apically.

Remarks. According to the key of Negrobov et al. (2000), the new species will run to C. nudisetus Negrobov et Maslova, 1995 but can be distinguished from the latter by the flattened lateral epandrial lobe with waved distal margin; surstylus stout, which flexes almost in a right angle at base.

Based on the key of Becker (1922), the new species will run to couplet 3, but differs from all species under the couplet by blackish brown femora and yellow tibiae.

Figures

FIGURE 5. Chrysotus biprojicienus sp. nov., (A) male terminalia, left lateral view; (B-C) female terminalia (B, dorsal view; C. lateral view).