Rheocricotopus (Psilocricotopus) rotundus, Liu, Wenbin, Lin, Xiaolong & Wang, Xinhua, 2014

Liu, Wenbin, Lin, Xiaolong & Wang, Xinhua, 2014, A review of Rheocricotopus (Psilocricotopus) chalybeatus species group from China, with the description of three new species (Diptera, Chironomidae), ZooKeys 388, pp. 17-34 : 25-26

Rheocricotopus (Psilocricotopus) rotundus sp. n. Figs 7-11

Diagnosis.

The adult male of the new species can be distinguished from known species of the genus by the following combination of characters: low AR 0.25-0.29; superior volsella rounded.

Description.

Male (n = 2).

Total length 1.58-1.98 mm. Wing length 0.86-1.20 mm. Total length/wing length 1.66-1.84. Wing length/length of profemur 1.74-2.61.

Coloration. Head and abdomen yellow brown, thorax without distinct pattern.

Head. Antenna as in Fig. 7. AR 0.25-0.29. Ultimate flagellomere 88-118 μm long. Temporal setae 3-4, including 1-2 inner verticals and 2 outer verticals. Clypeus with 6-12 setae. Tentorium 115-130 μm long, 23-25 μm wide. Stipes 115-118 μm long, 4-5 μm wide. Palpomere lengths (in μm): 48-53, 30-45, 48-60, 68-90, 123-163. L: 5th/3rd 2.56-2.71.

Wing (Fig. 8). Anal lobe normally developed. VR 1.17-1.19. Costal extension 30-38 μm long. Brachiolum with 1 seta. R with 1-3 setae. Remaining veins bare. Squama with 2 setae.

Thorax (Fig. 9). Antepronotum with 4 lateral setae. Dorsocentrals 6-11; acrostichals 6-8, prealars 3. Scutellum with 2-6 setae. Humeral pit moderately large, ovoid.

Legs. Spur of fore tibia 23-40 μm long; spurs of mid tibia 13-18 μm long and 12-15 μm long; spurs of hind tibia 27-38 μm and 13-15 μm long. Hind tibial comb with 8-16 spines, 13-27 μm long. Width at apex of fore tibia 25-40 mm, of mid tibia 25-38 mm, of hind tibia 23-40 mm. Lengths and proportions of legs as in Table 3.

Hypopygium (Figs 10-11). Anal point triangular, 20-28 μm long, with 4 lateral setae each side. Laterosernite IX with 2 setae. Phallapodeme 48-50 μm long. Transverse sternapodeme arcuate with normally oral projection, 33-40 μm long. Gonocoxite 125-135 μm long. Superior volsella rounded, plate-shaped and sclerotized, 28-38 μm long and 20-27 μm wide, covered with 8 short setae and a few microtrichia. Gonostylus 55-70 μm long, with distinct, triangular crista dorsalis. Megaseta 8-10 μm long. HR 1.93-2.27. HV 2.82-2.87.

Type material.

Holotype: ♂ (BDN. G5A42), China, Zhejiang Province, Jinhua City, Pan’an County, Dapanshan National Nature Reserve, 28°98'02"N, 120°52'63"E, 18.vii.2012, sweeping, Lin XL. Paratype (1): 1♂, Yunnan Province, Dali Bai Autonomous Prefecture, Eryuan County, Niujie Town, 26°25'55"N, 99°98'90"E, sweeping, Wang BX.

Etymology.

The specific name is an adjective, from Latin rotundus, meaning rounded, referring to rounded superior volsella.

Remarks.

The new species resembles Rheocricotopus (Psilocricotopus) notabilits Caspers, 1987 in the following combination of characters: low AR; humeral pit medium, ovoid; the shape of anal point. But the new species can be separated from latter species on the basis of following characters: (1) costal extension of the new species (30-38 μm) much shorter than Rheocricotopus (Psilocricotopus) notabilits Caspers (72 μm); (2) anal lobe of the new species developed, which reduced in Rheocricotopus (Psilocricotopus) notabilits Caspers; and (3) crista dorsalis of the new species distinct, triangular subapical, which pronounced, rounded in Rheocricotopus (Psilocricotopus) notabilits Caspers.

Female and immature stages unknown.