Rheotanytarsus brevipalpus, 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 : 15-16

Rheotanytarsus brevipalpus sp. n. ( Figs. 17–18 )

Type material. Holotype male (BDN No. 20228), China, Ningxia Autonomy Region, Liupan Mountain, Erlong River, 1750m. 7. VIII. 1987, Leg. X. Wang, sweep net.

Etymology. From Latin brevis, short and palp, referring to the 4th palpomere being shorter than the 3rd, which is unique within the genus.

Diagnosis. The species can be separated from other members of the trivittatus group by having palpomere 4 shorter than palpomere 3. It is similar to R. nuamea Kyerematen & Andersen and R. scutulatus Kyerematen & Andersen (Kyerematen & Andersen 2002) , but has a more gradually tapering gonostylus than both species, lacks the basal lamelliform seta of the median volsella present in R. nuamae , and has an AR of about 0.50 as opposed to 0.25 in R. scutulatus .

Male imago (n=1)

Total length 2.84 mm. Wing length 1.90 mm. Total length / wing length 1.49. Wing length / profemur length 2.21. Coloration pale with light brown vittae.

Head. Antenna with 13 flagellomeres. Ultimate flagellomere 320 µm long. AR 0.50. Temporals 9, including 4 inner verticals, 3 outer verticals and 2 postorbitals. Clypeus with 17 setae. Tentorium 116 µm long, width 36 µm. Palpomere lengths (in µm): 40; 42; 122; 114; 224. Fifth / third palpmere 1.84.

Wing ( Fig. 17 ). VR 1.51, Cu length 880 µm.

Thorax. Acrostichals 13; dorsocentrals 8; prealars absent; scutellum with 6 setae.

Legs. Spur of front tibia 32 µm. Spurs of middle tibia 30 and 30 µm long, of hind tibia 38 and 48 µm long. Combs of middle leg composed of 20 and 12 free teeth, hind leg composed of 20 and 8 free teeth (Table 8):

Hypopygium ( Fig. 18 ). Anal tergite bands of V type, widely separated medially, extending almost to base of anal point. Tergite IX with 8 setae, 2 between anal crest, base of anal point each side with 3. Anal point 40 µm long. Crests well developed, basally open and V shaped. Phallapodeme 80 µm long. Transverse sternapodeme 40 µm long, straight, with strong oral projections. Gonocoxite 136 µm long. Superior volsella 58 µm long, subtriangular, with 6 dorsal in addition to 2 inner marginal setae, with 1 ventral seta. Inferior volsella 75 µm long. Median volsella 46 µm long, with some lamellae fused into plates without apical points. Gonostylus 124 µm long. HR 1.10; HV 2.29.

Distribution. The present species is known from Liupan Mountain, Ningxia Autonomy Region in northern China (Palaearctic China).

Figures

FIGURES 14 – 18. Figs. 14 – 16. Rheotanytarsus fundus sp. n. Holotype, male imago: 14. Wing, 15. Hypopygium, 16. Median volsella. Figs. 17 – 18. Rheotanytarsus brevipalpus sp. n. Holotype, male imago: 17. Wing, 18. Hypopygium