Rheotanytarsus quadratus, 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 : 9-11

Rheotanytarsus quadratus sp. n. ( Figs. 10–11 )

Type material. Holotype male (BDN No. 20805), China, Fujian Province, Nanping City, Maodi Country, Mangdangshan. IX. 23. 2002. Leg. Zh Liu. 1 paratype male (BDN No. 20395), China, Fujian Province, Yongtai Country, IX. 17. 2002. Leg. Zh Liu, light trapped.

Etymology. From Latin quadratus , referring to the rectangular superior volsella, which is unusual in the genus.

Diagnosis. The species belongs to the muscicola group ( Saether & Kyerematen 2001). [ Kyerematen & Andersen (2002) used the phaselus group, which was an earlier division into species groups and is now included in the muscicola group.] The species is similar to R. subtilis Kyerematen & Andersen from Costa Rica and R. ramirezi Kyerematen & Andersen from Mexico, but differs from both by having a higher antennal ratio (0.7–0.8, as opposed to about 0.4), and having anal tergite bands of the V type as opposed to the H type.

Male imago (n=2)

Total length 2.20–2.40 mm. Wing length 1.16–1.76 mm. Total length / wing length 1.76–1.90. Wing length / profemur length 1.69–1.74. Coloration pale, eyes black. Head. Antenna with 13 flagellomeres. Ultimate flagellomere 328–416 µm long. AR 0.71–0.80. Temporal (n=1) 6 composed of 2 inner, 3 outer and 1 postorbitals. Clypeus with 17 setae. Tentorium 94–100 µm long, width 22 µm. Palpomere lengths (in µm): 32–40; 36; 96; 102–110; 160–190.

Wing ( Fig. 10 ). VR 1.44–1.52. Cu length 560–632 µm.

Thorax. Acrostichals 10–16; dorsocentrals 7–10; prealars 1; scutellum with 4–5 setae. Legs. Spur of front tibia 16–24 µm. Spurs of middle tibia 32–36 and 27–29 µm long, and of hind tibia 34–38 and 28–30 µm long. Combs of middle leg composed of 10–12 and 8–10 free teeth, hind leg composed of 13 and 10–12 free teeth ( Table 5 ):

P1 688–780 296–380 940–980 416–460 P2 640–740 440–528 280–320 120–144 P3 688–780 520–630 416–464 216–260

Hypopygium ( Fig. 11 ). Anal tergite bands of V type, widely separated medially. Tergite IX with 6–8 setae. Anal point 32–34 µm long, slightly spatulate. Crests well developed, basally open and Y shaped. Phallapodeme 44–60 µm long. Transverse sternapodeme 28– 34 µm long, straight, and with oral projections. Gonocoxite 100–104 µm long. Superior volsella 22–24 µm long, squared, with 4–6 dorsal, 2 marginal setae, and 1 ventral seta. Inferior volsella 64–72 µm long. Median volsella 42–48 µm long, almost all lamellae fused into large plate. Gonostylus abruptly narrowed at apical 1/2 to rounded apex, 80–100 µm long. HR 1.04–1.25; HV 2.40–2.75.

Distribution. The species is known from Fujian province in southern China (Oriental Region).

Figures

FIGURES 10 – 13. Figs. 10 – 11. Rheotanytarsus quadratus sp. n. Holotype, male imago: 10. Wing, 11. Hypopygium. Figs. 12 – 13. Rheotanytarsus apiculus sp. n. Holotype, male imago: 12. Wing, 13. Hypopygium

Tables

TABLE 5. Rheotanytarsus quadratus sp. n. Lengths of legs (in µm). fe ti ta 1 ta 2

ta3 ta4	ta5	LR
P1 304–380 256–320	104–120	2.59–3.18
P2 88–112 48–64	40–50	0.61–0.64
P3 200–240 120–144	70	0.74–0.80