Polypedilum (Tripodura) udominutum Niitsuma

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 : 35-36

Polypedilum (Tripodura) udominutum Niitsuma

( Figure 16 )

Polypedilum (Tripodura) udominutum Niitsuma, 1992: 50 .

Polypedilum sp 15. SC. 232, 233, 234; Song et al. 2016: 542.

Material examined. 3 males. CHINA, Guangxi Zhuang Autonomous Region, Hechi City, Luocheng County, Xiaochanggan Town, 10. IV. 2015; light trap, C. Song.

Diagnostic characters. The species can be easily distinguished from other members of the subgenus by the combination of characters: slender anal point without basal process, wing with faint markings and pad-like superior volsella entirely pubescent having two long apical setae.

Male imago (n=3, when otherwise stated). Total length 2.02–2.40 mm (2). Wing length 1.22–1.28 mm. Total length/ wing length 1.66–1.88 (2). Wing length/ length of profemur 2.20–2.36.

Coloration. Head brown. Thorax dark brown with yellow halteres. Leg and abdominal segments yellowish brown.

Head. AR 0.80 (1). Ultimate flagellomere 360 µm (1) long. Temporal setae 9. Clypeus with 17–22 setae. Tentorium 108–110 µm long, 25–28 µm wide, stipes 108–115 µm long. Palpal segments missing.

Wing ( Figure 16A ). Wing with faint markings as in figure 15A. VR 1.22–1.31. R with 14–18 setae, R1 with 9 (3), R4+5 with 17–22. Squama with 3–4 setae.

Thorax. Dorsocentrals 10–12, acrostichals 11–12, prealars 3 (3) Scutellum with 3–4 setae.

Legs. Terminal scale ( Figure 15B ) of front tibia 30–35 µm long, triangular and apically pointed. Spur of middle tibia 48–53 um long including 23–25 µm long comb, un-spurred comb 22–23 µm long, spur of hind tibia 48–53 µm long including 23–25 µm long comb, un-spurred comb 20–25 µm long. Width at apex of front tibia 35–38 µm, of middle tibia 40–43 µm, of hind tibia 45–48 µm. Lengths (in µm) and proportions of legs as in Table 1 .

Hypopygium ( Figure 16C, D ). Tergite IX with 3–4 median setae. Laterosternite with 2 setae. Anal point 43–45 µm long, slender and without lateral projection. Phallapodeme 65–88 µm long; transverse sternapodeme 35–38 µm long. Gonocoxite 115–125 µm long. Superior volsella ( Figure 16C ) pad–like, expanded distally, entirely pubescent and with 2 long apical setae. Inferior volsella 85–88 µm long, with 11–16 oral setae on distal 1/3 and an apical seta. Gonostylus 125–130 µm long, with 5–6 long setae along inner margin. HR 0.92–0.96, HV 1.62–1.85.

Distribution. The species distributes in Japan and Oriental China.

Remarks. The species is closely related to P. (T.) unifascia (Tokunaga) but is separated from the latter by the anal point lacking a basal process in male hypopygium ( unifascia having distinct basal process) and in having two markings in the cell r4+5 ( unifascia only having one dark marking in cell r4+5). AR of Chinese specimens is slight higher (0.80 comparing to 0.23–0.28 in Nitsuma’s descriptions). It is firstly recoded in China.

Figures

FIGURE 16 A – D. Polypedilum (Tripodura) udominutum Niitsuma. A. Wing. B. Fore tibial scale. C. Superior volsella. D. Hypopygium, dorsal and ventral view.

FIGURE 15 A – D. Polypedilum (Tripodura) trapezium Zhang & Wang sp. n. A. Wing. B. Fore tibial scale. C. Superior volsella. D. Hypopygium, dorsal and ventral view.