Polypedilum (Polypedilum) coalitum, Zhang, Ruilei & Wang, Xinhua, 2008

Zhang, Ruilei & Wang, Xinhua, 2008, Three new species of Polypedilum s. str. Kieffer from China, with L-shaped superior volsella (Diptera: Chironomidae), Zootaxa 1702, pp. 61-68 : 62-63

Polypedilum (Polypedilum) coalitum sp. nov.

( Fig. 1 )

Type material: Holotype male, CHINA: Hainan Province, Changjiang County, Bawangling Nature Reserve, 11.v.1989, light trap, X. Wang (BDN. No. 06041). Paratypes: 2 males, data as in holotype.

Etymology: From Latin coalescere, to grow together, referring to the fusion of palpomeres II and III.

Diagnostic characters: The combination of four palpomeres (palpomeres II and III fused) and vein R1 without setae is unique within the subgenus.

Male (n = 3)

Total length 2.38–2.65 mm. Wing length 1.45–1.53 mm. Total length / wing length 1.64–1.71. Wing length / length of profemur 2.21–2.34.

Coloration. Head brown. Thorax brown with darker median vittae, postnotum, scutellum, anepisternum and dorsal one-third of preepisternum; halteres dark brown. Legs yellow with brown fore femora and tibiae. Abdominal segments entirely brown.

Head. Frontal tubercles absent. AR 1.20–1.34; ultimate flagellomere 420–470 µm long. Temporal setae 10–11, including 3–4 inner verticals, 4–5 outer verticals, and 2–3 postorbitals. Clypeus with 9–12 setae. Tentorium 88–95 µm long, 20–25 µm wide. Palpomeres II and III fused ( Fig. 1 A); palpomere lengths (in µm): 25–30, 90–115, 80–85, 138–150.

Wing ( Fig. 1 B). VR 1.18–1.24. R with 10–12 setae; R1 without setae; R4+5 with 0–4 setae. Squama with 4– 5 setae. Anal lobe weak.

Thorax. Dorsocentrals 11–15; acrostichals 9–12; prealars 4–5. Scutellum with 5–7 setae.

Legs. Scale of foretibia 25–30 µm long, with rounded apex ( Fig. 1 C). Spur of midtibia 40–50 µm long, including 23–28 µm long comb; un-spurred comb 20–23 µm long. Spur of hind tibia 50–63 µm long, including 23–28 µm long comb; un-spurred comb 20–23 µm long. Width at apex of foretibia 40–43 µm, of midtibia 43–45 µm, of hind tibia 43–55 µm. Lengths (in µm) and proportions of legs as in Table 1 .

Hypopygium ( Fig. 1 D–F). Tergite IX with 20–25 median setae. Anal tergite band well developed, completely surrounding median setae. Laterosternite with 2–3 setae. Anal point 50–58 µm long, slender, tapering, with lateral setae basally. Phallapodeme 70–78 µm long, transverse sternapodeme 31–42 µm long. Gonocoxite 140–148 µm long. Superior volsella ( Fig. 1 D) strongly bent medially, with 1 strong lateral seta medially and 1 weak subapical seta. Inferior volsella 123–138 µm long, slender, swollen apically, with 1 strong apical seta projecting caudad, and 8–10 orally directed setae, some of which are split apically. Gonostylus 158–163 µm long, with 5–6 long setae along inner margin and 1 apical seta. HR 0.89–0.92; HV 1.50–1.68.

Distribution. The species was collected in a subtropical mountain area on the Hainan Island in Oriental China.

Figures

FIGURE 1. Polypedilum (Polypedilum) coalitum sp. nov., male imago. A. Palp. B. Wing. C. Fore tibial scale. D. Superior volsella. E. Hypopygium, dorsal view. F. Hypopygium, ventral view.

Tables

TABLE 1. Lengths (in µm) and proportions of legs of Polypedilum (Polypedilum) coalitum sp. nov., male (n = 3).

fe	ti	ta1	ta2	ta3	ta4	ta5	LR
p1 620–690	345–370	820–890	500–600	310–360	190–225	90–105	2.30–2.44
p2 680–730	540–570	320–350	180–200	115–130	60–80	40–55	0.59–0.63
p3 690–750	590–650	520–560	265–300	200–230	125–150	65–75	0.88–0.92