Rheotanytarsus polychaetus, Wang, Xinhua & Guo, Yuhong, 2004

Wang, Xinhua & Guo, Yuhong, 2004, A review of the genus Rheotanytarsus Thienemann & Bause from China (Diptera: Chironomidae: Tanytarsini), Zootaxa 650, pp. 1-19 : 5-7

Rheotanytarsus polychaetus sp. n. ( Figs. 6–7 )

Type material. Holotype male (BDN No. 08117), China: Xizang Autonomic Region, Chayu County. 8. VI. 1988, coll. X Wang.

Etymology. From Greek polys, many and chaite, hair, referring to more dorsocentrals and median volsella lamellae and the setae on tergite IX.

Diagnosis. The species belongs in the aquilus group. It differs from other members of the group except, R. kuantanensis , by having 12 flagellomeres combined with a non­spatulate anal point. It differs from R. kuantanensis by having a significant higher number of setae on the thorax and tergite IX and more lamellae on the median volsella.

Male imago (n=1)

Total length 2.28 mm. Wing length 1.40 mm. Total length / wing length 1.63. Wing length / profemur length 2.00. Coloration pale, eyes black.

Head. Antenna with 12 flagellomeres. Ultimate flagellomere 120 µm long. AR 0.21. Temporal setae consisting of 5 inner verticals and 3 outer verticals, postorbitals not measurable. Clypeus with 16 setae. Tentorium 100 µm long, width 24 µm. Palpomere lengths (in µm): 40; 36; 96; 110; 190.

Wing ( Fig. 6 ). VR 1.47 and Cu length 624 µm.

Thorax. Acrostichals 12; dorsocentrals 13; prealars 1. Scutellum with 10 setae. Legs. Spur of front tibia 20 µm. Spurs of middle tibia 42 and 28 µm long, of hind tibia 48 and 46 µm long. Combs of middle leg composed of 20 and 10 free teeth, hind leg of 20 and 18 free teeth ( Table 3):

fe ti ta1 ta2 ta3 ta4 ta5 LR P1 700 376 ­ ­ ­ ­ ­ ­

P2 700 560 ­ ­ ­ ­ ­ ­

P3 760 660 450 280 230 120 70 0.68

Hypopygium ( Fig. 7 ). Anal tergite bands nearly horizontal, separated medially. Tergite IX with 22 dorsal setae. Anal point 30 µm long. Crests well developed, basally open, Yshaped. Phallapodeme 60 µm long. Transverse sternapodeme 42 µm long, straight, with oral projections. Gonocoxite 120 µm long. Superior volsella 32 µm long, bulbous, with 4­ 5 dorsal in addition to 2 inner marginal setae. Inferior volsella 70 µm long. Median volsella 55 µm long, markedly curved with lamellae setae fused into plate. Gonostylus gradually tapered to rounded apex, 110 µm long. HR 1.09; HV 2.07.

Distribution. The species is known in the Chayu Country, Xizang (Oriental China).

Figures

FIGURES 6 – 9. Figs. 6 – 7. Rheotanytarsus polychaetus sp. n. Holotype, male imago: 6. Wing, 7. Hypopygium. Figs. 8 – 9. Rheotanytarsus liuae sp. n. Holotype, male imago: 8. Wing, 9. Hypopygium