Chrysotus fuscitibialis, 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 : 14-15

7. Chrysotus fuscitibialis sp. nov.

( Fig. 7 )

Diagnosis. Eyes contiguous on face. Postocular setae black. Proboscis brown, palpus brown. All coxae blackish; femora blackish. Squama yellow with brown setulae. Halter pale. Male terminalia with rather long and acute apically ventral hypandrial process. Proximal portion of hypandrium with one rather small projection and another very large projection.

Description. Male: Body length 2.3 mm, wing length 2.0 mm. Head: Metallic green with pale gray pollinosity; eyes contiguous on face. Setulae and setae on head black, postocular setae (including posteroventral setulae) black. Antenna black; first flagellomere subtriangular, 0.75 times as long as wide; arista black, short pubescence. Proboscis brown with brown setulae; palpus 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 brownish; all tarsi from tip of tarsomere 1 onwards brownish. Setulae and setae on legs black. Mid and hind coxae each with 1 outer seta. Fore femur with 2 pv apically, mid femur with 3 pv apically, hind femur with 3 av apically. Fore tibia with 1 ad, apically 3 short setae; mid tibia with 2 ad and 2 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 64: 31: 19: 11: 9: 8; LII 78: 40: 20: 15: 10: 8; LIII 90: 29: 21: 13: 10: 10. Wing: Hyaline, veins black; R4+5 and M1+2 parallel apically, CuAx ratio 0.3. Squama yellow with brown setulae. Halter pale. Abdomen: Dark metallic green with pale gray pollinosity; setulae and setae on abdomen black. Male terminalia ( Fig. 7 ). Epandrium with angular projection posteriorly. Ventral projection of epandrium with end pointed, withdrawn back from level of distal margin of lateral epandrial lobe. Lateral epandrial lobe arched apically, although with obtuse angle in antero-distal margin, bearing long and short seta, respectively. Surstylus slightly curved apically. Cercus short and wide. Hypandrium with ventral process, rather long and acute apically. Proximal portion of hypandrium with two projections, one rather smaller and another very large. Postgonite with strip-like arms and knife-like anterior process, which stand out from epandrium. Female: Unknown.

Type material. HOLOTYPE ɗ, Guizhou: Anshun, Jiaozishan, 1400 m, 26º20’N, 105º57’E, 17.VII.1994, LM Wei, CG Wu and X Wei.

Etymology. From the Latin fusc “brown” and tibial “tibial”, meaning brown tibia.

Remarks. The new species is related to C. xinanus sp. nov., but can be distinguished from the latter by palpus and proboscis brown; cercus with rounded arched posterior margin and hypandrium with ventral projection pointed apically.

According to the key of Negrobov et al. (2000), the new species will run to C. nudisetus Negrobov et Maslova, 1995 , but can be separated from the latter by ventral projection of epandrium with end withdrawn back from level of distal margin of lateral epandrial lobe; hypandrium with only a ventral process, which is rather long and acute apically.

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 yellowish brown tibiae.

Figures

FIGURE 7. Chrysotus fuscitibialis sp. nov., male terminalia, left lateral view.