Polypedilum (Uresipedilum) dilatum, Zhang & Wang, 2004

Zhang, Ruilei & Wang, Xinhua, 2004, Polypedilum (Uresipedilum) Oyewo and Saether from China (Diptera: Chironomidae), Zootaxa 565 (1), pp. 1-38 : 17-19

Polypedilum (Uresipedilum) dilatum sp. n.

( Fig. 7 )

Type material: Holotype male ( BDN No. 09243): CHINA: Shannxi , Ningshan County, Huoditang, 14. VIII. 1994, B. Ji., sweep net.

Etymology: From Latin dilato, enlarge, refers to the expended inferior volsella.

Diagnostic characters: Differs from other members of the subgenus in having pointed apicomedial projection of the superior volsella and the expended inferior volsella.

Male imago (n = 1)

Total length 2.44 mm. Wing length 1.78 mm. Total length/ wing length 1.65. Wing length /length of profemur 2.29.

Coloration. Head and thorax brown with darker vittae, postnotum and preepisternum. Abdominal segments brown except gonostylus yellow brown. Legs yellow.

Head. AR 1.11. Ultimate flagellomere 525 m long. Temporal setae 12; including 4 inner verticals; 5 outer verticals and 3 postorbitals. Clypeus with 23 setae.

Wing ( Fig. 7A ). VR 1.32. Brachiolum with 1 seta, R with 19; R 1 with 18; R 4+5 with 40. Squama with 13 setae.

Thorax. Dorsocentrals 20, including 3 humerals; acrostichals 14; prealars 6. Scutellum with 18 setae.

Legs. Terminal scale ( Fig. 7B ) of front tibia with small spine, 44 m long; spur on median tibiae 47 µm long including 21 m long comb, un­spurred comb 18 m long, spur on posterior tibia 52 m long including 26 m long comb, un­spurred comb 23 m long. Width at apex of front tibia 47 m, of middle tibia 49 m, of hind tibia 52 m. Lengths (in m) and proportions of legs (Table 7):

TABLE. 7. Polypedilum (Uresipedilum) dilatum sp. n. Lengths of legs (in m).

Hypopygium ( Figs. 7C–E ). Anal tergite bands fused basal to median anal tergite seta. Anal tergite with 5 median setae, laterosternite with 2 setae. Anal point tapering to parallel­sided with lateral setae. Phallapodeme 68 m long; transverse sternapodeme 26 m long. Gonocoxite 153 m long. Superior volsella 60 m long, base with 2 inner and 1 apical seta and microtrichiae present; apicomedial projection short and apically pointed. Inferior volsella 101 m long, gradually broadened and widest at apex, with 14 oral setae and prominent apical seta. Gonostylus 122 m long with 4 setae along inner margin and 1 apical seta. HR 1.25. HV 2.41.

Distribution: The species was collected in Qinling Mountain area in Shannxi Province (Oriental China).

Remarks: The species resembles new species P. (U.) lateralum sp. n., but can be distinguished by the shape of the superior and inferior volsellae. The latter has a slightly bulging inner margin of the superior volsella and inferior volsella nearly parallel­sided, not widest at apex.

Figures

FIGURE 7. Polypedilum (Uresipedilum) dilatum sp. n. A.Wing. B. Fore tibia scale. C. Superior volsella. D. Dorsal view of hypopygium. E. Ventral view of hypopygium.