Rheotanytarsus pinderi Yao & Liu 2022, sp. n.

Rheotanytarsus pinderi Yao & Liu sp. n.

(Figs. 1B, 3A–E)

Type material. Holotype: male (NKU: LGS79), China, Qiandongnan Miao and Dong Autonomous Prefecture, Leigongshan National Nature Reserve, Fangxiang, Getoucun country, 15–25. i. 2020, malaise trap, leg. H.J. Yu.

Etymology. Named after Prof. Clive Pinder, for his outstanding contribution to the knowledge of Chironomidae; noun in nominative case.

Diagnosis. The species can be distinguished from known species of Rheotanytarsus by the following combination of characters: antenna with 13 flagellomeres, and AR 0.18; thorax with brownish-yellow stripes and postnotum dark brown; tergite IX approximately triangular; superior volsella oval, with a knob-like structure; median volsella with apically broader stem and forked apical setae; gonostylus gradually tapered and curved apically, with rounded apex.

Description. Adult male (n = 1)

Total length 2.21 mm. Wing length 1.44 mm. Total length/wing length 1.54. Wing length/length of profemur 2.35.

Colouration (Fig. 1B). Thorax pale brown with brownish-yellow stripes and postnotum dark brown, legs pale brown with apical portion of femur slightly darker, and abdomen pale yellow.

Head. Antenna with 13 flagellomeres, ultimate flagellomere 92 μm long. AR 0.18, relatively small. Temporal setae 7. Clypeus with 18 setae. Tentorium 83 μm long, 11 μm wide. Palpomere lengths (in μm): 37, 29, 62, 87, 148; Pm5/Pm3 2.39. Third palpomere with 2 sensilla clavata distally.

Thorax. Dorsocentrals 9; acrostichals 9; prealar 1. Scutellum with 6 setae. Halteres with 7 setae.

Wing (Fig. 3A). VR 1.78. Brachiolum with one seta, Sc bare, R with 13 setae, R 1 with 26 setae, R 4+5 with 57 setae, RM with one seta, M 1+2 with 44 setae, M 3+4 with 28 setae, false vein with 79 setae, Cu with 12 setae, Cu 1 with 21 setae, PCu with 49 setae, An with 24 setae, remaining veins bare. Cell r 4+5 with c. 250 setae, m with 3 setae, m 1+2 with c. 250 setae, m 3+4 with c. 100 setae, cu+an with c. 150 setae.

Legs. Tibia and all tarsomeres of fore leg used for DNA extraction. Combs of mid tibia 24 μm wide with 27 μm long spur, and 33 μm wide with 25 μm long spur; combs of hind tibia 32 μm wide with 40 μm long spur, 36 μm wide with 34 μm long spur. Tarsomere 1 of mid leg with three sensilla chaetica. Lengths (in μm) and proportions of legs as in Table 2.

Hypopygium (Figs. 3 B-E). Tergite IX 66 μm long, with eight median setae at base of anal point; anal tergal bands well separated and of V-type with a small tilt angle. Anal point 33 μm long, with slightly swollen apex, bearing five lateral setae on each side; crests somewhat parallel and nearly reaching apex of anal point. Transverse sternapodeme 31 μm long, with tiny oral projections. Phallapodeme 78 μm long. Gonocoxite 95 μm long. Gonostylus 81 μm long, gradually tapered and curved apically, with rounded apex. Superior volsella (Fig. 3D) 36 μm long, oval, with two anteromedian setae, and with two (left) or three (right) thicker setae on a knob-like structure on dorsal. Digitus thumb-like, without seta. Median volsella (Fig. 3E) 126 μm long, well reaching beyond apex of inferior volsella, with long and foliate setae apically, some forked; stem covered with simple setae, slightly curved and apically broaden. Inferior volsella 58 μm long, curved and gradually swollen, with microtrichia. HR 1.17. HV 2.72.

Female and immatures. Unknown.

Remarks. The new species resembles Rheotanytarsus oss Cranston, 1997 by having similar shapes of superior volsella and median volsella, but can be separated from the latter species by the following combination characters: gonostylus curved apically, tergite IX approximately triangular, anal crests parallel-sided, whereas gonostylus not curved, tergite IX with rounded margin, anal crests of V-type in R. oss.