Rheocricotopus (Psilocricotopus) serratus, 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 : 26-28

Rheocricotopus (Psilocricotopus) serratus sp. n. Figs 12-15

Diagnosis.

The adult male of the new species can be distinguished from known species of the species group and the genus by the following combination of characters: crista dorsalis sawtooth-shaped, hyaline, high as megaseta; high HR (2.61-3.42) and HV (3.40-5.00).

Description.

Male imago (n = 4)

Total length 2.55-3.00, 2.73 mm. Wing length 1.33-1.95, 1.69 mm. Total length/wing length 1.44-1.94, 1.64. Wing length/length of profemur 2.21-2.35, 2.27.

Coloration. Head and abdomen yellow, thorax dark brown.

Head. AR 0.71-0.78, 0.74. Ultimate flagellomere 285-355, 323 μm long. Temporal setae 0-3, 1, including 0-1, 1 inner vertical; 0-2, 1 outer vertical and 0-1, 1 postorbital. Clypeus with 9-12, 10 setae. Tentorium 140-153, 148 μm long, 33-40, 38 μm wide. Stipes 65-75, 68 μm long, 3-7, 4 μm wide. Palpomere lengths (in μm): 35-70, 47; 48-58, 53; 103-123, 114; 118-155, 141; 205-238, 219. L: 5th/3rd 1.67-2.02, 1.92.

Wing (Fig. 12). Anal lobe slightly developed. VR 1.13-1.20, 1.17. Costal extension 50-88, 71 μm long. Brachiolum with 1 seta. R with 4-11, 7 setae. Remaining veins bare. Squama with 6-13, 9 setae.

Thorax (Fig. 13). Antepronotum with 1-7, 4 lateral setae. Dorsocentrals 6-9, 7; acrostichals 9-15, 12; prealars 3. Scutellum with 4-6, 5 setae. Humeral pit moderately large, egg-shaped.

Legs. Spur of fore tibia 40-48, 44 μm long; spurs of mid tibia 15-25, 19 μm and 15-20, 17 μm long; spurs of hind tibia 43-55, 48 μm and 18-23, 19 μm long. Hind tibial comb with 11-13, 12 spines, 30-50, 40 μm long. Width at apex of fore tibia 35-45, 41 mm, of mid tibia 36-45, 41 mm, of hind tibia 38-45, 43 mm. Lengths (in μm) and proportions of legs as in Table 4.

Hypopygium (Figs 14-15). Anal point triangular, pointed distally, 33-50, 41 μm long, 20-30, 24 μm wide, with 4-5, 5 lateral setae each side. Laterosernite IX with 2-3, 3 setae. Phallapodeme 23-28, 25 μm long. Transverse sternapodeme 18-33, 26 μm long. Gonocoxite 180-205, 195 μm long. Superior volsella triangular, 35-43, 40 μm long, with 7-8, 8 setae. Gonostylus 60-75, 67 μm long. Megaseta 13-15, 14 μm long. Crista dorsalis sawtooth-shaped, hyaline, high as megaseta. HR 2.61-3.42, 2.91. HV 3.40-5.00, 4.09.

Type material.

Holotype: ♂ (BDN. 10058), China, Yunnan Province, Dali Bai Autonomous Prefecture, Eryuan County, Niujie Town, 26°25'55"N, 99°98'90"E, light trap, Zhou CF. Paratypes (3): 1♂, Zhejiang Province, Qingyuan County, Baishanzu National Nature Reserve, 27°73'23"N, 119°19'06"E, 15.vii.1994, Ji BC; 1♂, Tibet, Xigaze, Nielamu County, 27°98'73"N, 85°98'32"E, 21.9.1987, light trap, Deng CY; 1♂, Sichuan Province, Xiangcheng County, 28°93'44"N, 99°79'72"E, 12.vi.1996, light trap, Wang XH.

Etymology.

The specific name is an adjective, from Latin serratus, meaning sawtooth, referring to the sawtooth-shaped crista dorsalis.

Remarks.

The new species resembles Rheocricotopus (Psilocricotopus) himalayensis Chaudhuri & Sinharay, 1983 in the triangular anal point, but it can be separated from the latter species on the basis of following characters: (1) costal extension of the new species much longer (50-88 μm), than Rheocricotopus (Psilocricotopus) himalayensis Chaudhuri & Sinharay (25 μm); (2) humeral pit in the new species medium, ovoid, which rounded in the latter species; (3) crista dorsalis sawtooth-shaped, hyaline in the new species, which moderately pronounced in the latter species.

Female and immature stages unknown.