Polypedilum (Uresipedilum) minimum, Lin, Xiaolong, Qi, Xin, Zhang, Ruilei & Wang, Xinhua, 2013

Lin, Xiaolong, Qi, Xin, Zhang, Ruilei & Wang, Xinhua, 2013, A new species of Polypedilum (Uresipedilum) Oyewo & Saether, 1998 from Zhejiang Province of Oriental China (Diptera, Chironomidae), ZooKeys 320, pp. 43-49 : 44-47

Polypedilum (Uresipedilum) minimum sp. n. Figures 1-7

Diagnosis.

The male adult can be distinguished from known species of the subgenus by the following combination of characters: low AR (0.27); frontal tubercles present; fore tibial scale rounded; anal point broad; superior volsella strongly projected posteriorly, pointed at apex, without microtrichium; high HV (4.90).

Description.

Male adult (n = 1). Total length 1.47 mm. Wing length 0.89 mm. Wing length/length of profemur 2.98.

Coloration. Head, legs and abdomen yellow. Thorax yellow with brown vittae, postnotum and preepisternum.

Head. AR 0.27. Antenna with 13 flagellomeres, ultimate flagellomere 93 μm long (Fig. 1). Frontal tubercles 38 μm long, 15 μm wide at base. Temporal setae 7, includ ing 2 inner verticals, 4 outer verticals and 1 postorbital. Clypeus with 15 setae. Tentorium 70 μm long, 10 μm wide. Stipes 75 μm long, 10 μm wide. Palpomeres length (in μm): 18, 15, 38, 55, 103. L: 5th/3rd 2.73.

Wing (Fig. 2). VR 1.54. Brachiolum with 1 seta, R with 11 setae, R1 with 6 setae, R4+5 with 15 setae. Squama with 6 setae.

Thorax (Fig. 3). Acrostichals 8; dorsocentrals 11; prealars 3. Scutellum with 4 setae.

Legs. Terminal scale (Fig. 4) of fore tibia rounded, 15 μm long, without spine. Spur of mid tibia 25 μm long, comb 10 μm long; unspurred comb 15 μm long. Spur of hind tibia 25 μm long, comb 10 μm long; unspurred comb 10 μm long. Apex of fore tibia 25 μm wide, of mid tibia 23 μm wide, of hind tibia 38 μm wide. Mid ta1 without sensilla chaetica. Lengths (in μm) and proportions of legs in Table 1.

Hypopygium (Figs 5-6). Tergite IX with 4 strong median setae. Laterosternite IX with 1 seta. Anal point broad, 18 μm long, with swollen, rounded apex. Phallapodeme 34 μm long; transverse sternapodeme 13 μm long. Gonocoxite 62 μm long, with 2 long setae. Superior volsella (Fig. 7) 16 μm long, with 3 basal inner setae and 1 strong apical seta, without microtrichium; apicomedial projection 17 μm long, pointed at apex. Inferior volsella 41 μm long, with 10 dorsal setae and 1 prominent apical seta. Gonostylus 30 μm long, apex blunt, with 3 setae along inner margin and 1 apical seta. HR 2.07. HV 4.90.

Type materials.

Holotype: adult male, China, Zhejiang Province: Jinhua City, Pan’an County, Dapanshan National Nature Reserve, 120.50°N, 29.00°E, 18.vii.2012, leg. Lin XL, sweep net.

Etymology.

From Latin minimum, little, referring to the small body length and antennal ratio.

Remarks.

The new species resembles Polypedilum (Uresipedilum) obtusum Townes, 1945, Polypedilum (Uresipedilum) aviceps Townes, 1945, Polypedilum (Uresipedilum) infundibulum Zhang & Wang, 2004, Polypedilum (Uresipedilum) surugense Niitsuma, 1992 and Polypedilum (Uresipedilum) paraviceps Niitsuma, 1992 in the general structure of hypopygium, but it can be separated by the superior volsella without microtrichium, which present in the latter species; the low antennal ratio (AR= 0.27), AR>1 in the latter species. The new species most resembles Polypedilum (Uresipedilum) breviplumosum Zhang & Wang, 2004 in the low antennal ratio (AR= 0.22-0.23), but it differs from the latter species by the following combination of characters in Table 2.