Polypedilum (Tripodura) dengae Zhang & Wang

Zhang, Ruilei, Song, Chao, Qi, Xin & Wang, Xinhua, 2016, Taxonomic review on the subgenus Tripodura Townes (Diptera: Chironomidae: Polypedilum) from China with eleven new species and a supplementary world checklist, Zootaxa 4136 (1), pp. 1-53 : 16

Polypedilum (Tripodura) dengae Zhang & Wang sp. n.

( Figure 6 )

Polypedilum sp.17 SC, song39, 40; Song et al. 2016: 542.

Type material. Holotype: male (BDN. 08029), CHINA: Xizang Autonomous region, Nyalam County, Zham Town, 21. IV. 1987, light trap, C. Deng. Paratypes: 11 males, as the holotype.

Etymology. Named in honor of Professor Deng who collected the material.

Diagnostic characters. Differs from other members of the subgenus by the lanceolate anal point, characteristic wing pattern and pad-like superior volsella.

Male imago (n=6). Total length 2.53–3.15, 2.78 mm. Wing length 1.50–1.98, 1.68 mm. Total length/ wing length 1.59–1.70, 1.66. Wing length/ length of profemur 2.50–2.86, 2.68.

Coloration. Head brown. Thorax yellowish brown with pale halteres. Abdominal segments yellow. Femur brown with pale sub-apical ring, the remain parts of legs yellowish brown.

Head. AR 0.28–0.40, 0.33. Ultimate flagellomere 170–230, 198 µm long. Temporal setae 13–14, 13, including 3–4, 3 inner verticals, 6–7, 6 outer verticals and 3–3, 3 postorbitals. Clypeus with 15–22, 18 setae. Tentorium 108– 125, 117 µm long, 20–25, 23 µm wide. Palpomere lengths (in µm): 30–40, 34; 25–45, 35; 83–95, 86; 90–108, 94; 183–190, 186..

Wing ( Figure 6A ). Wing with several markings, one at the base of cell r4+5, one in middle of cell r4+5, one at base of cell m3+4 and extended across vein Cu1, cell m1+2 and distal area of cell r4+5 with grey tract. VR 1.23–1.30, 1.27. R with 15–22, 18 setae; R1 with 10–15, 13; R4+5 with 22–32, 27 setae. Squama with 7–12, 10 setae.

Thorax. Dorsocentrals 15–23, 18, including 2–3, 3 humerals; acrostichals 13–19, 15; prealars 3–6, 4. Scutellum with 16–23, 19 setae.

Legs. Terminal scale ( Figure 6B ) of front tibia 30–43, 36 µm long, triangular with a small spur. Spur of middle tibia 43–58, 48 um long including 20–33, 24 µm long comb, un-spurred comb 18–30, 20 µm long, spur of hind tibia 40–53, 45 µm long including 18–30, 24 µm long comb, un-spurred comb 18–25, 21 µm long. Width at apex of front tibia 40–55, 44 µm, of middle tibia 40–50, 45 µm, of hind tibia 48–63, 53 µm. Lengths (in µm) and proportions of legs as in Table 1 .

Hypopygium ( Figure 6C, D ). Anal tergite band developed, fused at base. Tergite IX with 6–12, 9 median setae. Laterosternite with 1–3, 2 setae. Anal point lanceolate, 55–75, 66 µm long; lateral projection 13–15, 14 µm long. Phallapodeme 75–90, 83 µm long, transverse sternapodeme 33–43, 37 µm long. Gonocoxite 120–145, 131 µm long. Superior volsella ( Figure 6C ) pad–like, with 4–5 short setae on inner margin and 1 long seta on outer distal margin. Inferior volsella 100–118, 108 µm long, with 10–11 oral setae and 1 apical seta. Gonostylus 138–163, 148 µm long, with 5 long setae along inner margin. HR 1.03–1.14, 1.08. HV 1.65–1.80, 1.77.

Distribution. The species was collected from the Oriental China.

Remarks. P. (T.) dengae Zhang & Wang sp. n. resembles P. (T.) yaumounei Moubayed, 1992 in hypopygial morphology. P. (T.) dengae sp. n. has a low AR (0.28–0.40) comparing with P. (T.) yaumounei Moubayed (0.75– 0.86). The superior volsella of P. (T.) dengae Zhang & Wang sp. n. has one long seta on outer distal margin, but 2 in P. (T.) yaumounei Moubayed. The wing marking pattern is different in these two species.

Figures

FIGURE 6 A – D. Polypedilum (Tripodura) dengae Zhang & Wang sp. n. A. Wing. B. Fore tibial scale. C. Superior volsella. D. Hypopygium, dorsal and ventral view.