Chrysotus xinanus, 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 : 20-22

11. Chrysotus xinanus sp. nov.

( Fig. 11 )

Diagnosis. Eyes contiguous on face. Proboscis black, palpus black. All coxae blackish; femora blackish; apex of hind tibiae brownish. Squama pale with brown setulae. Halter pale. Male terminalia with hypandrial ventral process rounded apically.

Description. Male: Body length 2.5 mm, wing length 2.2 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, 0.7 times as long as wide; arista black, short pubescence. Proboscis black with black setulae; palpus black with 1 black apical seta. Thorax: Dark metallic green with pale gray pollinosity. Setulae and setae on thorax black; 6 strong dc, 7–8 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: Brown, all coxae blackish; femora blackish; tibiae yellowish brown; fore and mid tarsi from tip of tarsomere 1 onwards brownish, hind tarsus brown. Setulae and setae on legs black. Mid and hind coxae each with 1 outer seta. Fore femur with 2 pv apically; mid femur with 2 av apically; hind femur with 2–3 av apically. Fore tibia with 1 ad, apically 3 short setae; mid tibia with 2 ad and 3 pd, apically with 4 setae; hind tibia with 2 ad and 4 pd, apically with 4 setae. Relative lengths of tibia and 5 tarsomeres of legs LI 43: 24: 10: 7: 5: 5; LII 50: 30: 14: 10: 6: 5; LIII 64: 20: 16: 10: 5: 5. Wing: Hyaline, veins black; R4+5 and M1+2 parallel apically, CuAx ratio 0.3. Squama pale with brown setulae. Halter pale. Abdomen: Dark metallic green with pale gray pollinosity; setulae and setae on abdomen black. Male terminalia ( Fig. 11 A, paratype from Sichuan, Cifeng). Epandrium with angular projection posteriorly. Ventral projection of epandrium with end pointed, stands at level of distal margin of lateral epandrial lobe. Lateral epandrial lobe short and wide, flattened apically, bearing 2 setae. Surstylus curved. Cercus triangular, with seta. Hypandrium with ventral process rounded apically. Proximal portion of hypandrium with projection. Postgonite with two strip-like arms and anterior process, latter projects from epandrium and longer than arms. Female: Body length 2.7 mm, wing length 2.2 mm. Similar to male, except terminalia feature. Relative lengths of tibia and 5 tarsomeres of legs LI 78: 40: 20: 15: 9: 9; LII 100: 50: 22: 18: 10: 10; LIII 115: 34: 25: 16: 10: 10. Terminalia ( Figs. 11 A-B). Ventral view profile: 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, dorsal surface of each with crest bearing 5 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 wider strip-like, with apex dental and setose. In profile: both Tg8 and St8 widely separated from each other basally; St8 with fork-like end; St9 comma-shaped, apically long; St10 long, bent, stick-like, expanded apically, with group of setae apically; cercus longer diamond-like, bare.

Type material. HOLOTYPE ɗ, Yunnan: Lijing Yuquan Park, 2200 m, 14.VIII.1993 LM Wei and MH Liu. PARATYPES: 386 ɗ and 419Ψ were collected from Guizhou, Guangxi, Sichuan and Yunnan, 700-1800 m, 1993-2010, LM Wei, SG Jiang, WP Chao, DX Wang, MH Liu, B Long, ZH Yang, JL Wu, ZW Song, M Yan and QL Xiao.

Etymology. The specific name refers to the type localities of Xinan area, China (southwest China).

Remarks. The new species is related to both C. biprojicienus , sp. nov. and C. apicicaudatus , sp. nov., but distinguished by features provided in the key.

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 surstylus more curved than in the latter; hypandrium with only a ventral process.

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 11. Chrysotus xinanus sp. nov. (A) male terminalia, left lateral view; (B – C) female terminalia (B, dorsal view; C. lateral view).