Rheocricotopus (Psilocricotopus) brochus, 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 : 19-21

Rheocricotopus (Psilocricotopus) brochus sp. n. Figs 1-6

Diagnosis.

The adult male can be distinguished from known species of the species group and the genus by the following combination of characters: crista dorsalis tooth-liked; tergites I, II and IV yellow, tergite III mainly yellow with a brown circular area, other tergites brown.

Description.

Male imago (n = 12)

Total length 1.75-2.70, 2.18 mm. Wing length 1.25-1.60, 1.33 mm. Total length/wing length 1.35-1.78, 1.68. Wing length/length of profemur 1.76-2.31, 2.04.

Coloration. Head and thorax brown. Tergites (Fig. 1) I, II and IV yellow, tergite III mainly yellow but having a brown circular area, other tergites brown.

Head. AR 0.63-0.89, 0.72. Ultimate flagellomere 245-360, 284 μm long. Temporal setae 4-7, 5, including 1-3, 2 inner verticals; 1-3, 2 outer verticals and 0-2, 1 postorbital. Clypeus with 7-10, 8 setae. Cibarial pump, tentorium and stipes as in Fig. 2. Tentorium 75-140, 123 μm long, 13-25, 19 μm wide. Stipes 100-125, 118 μm long, 8-10, 8 μm wide. Palpomere lengths (in μm): 20-25, 23; 38-55, 47; 90-130, 105; 110-138, 120; 205-250, 232. L: 5th/3rd 1.92-2.67, 2.23. Third palpal segment with 2 sensilla clavata.

Wing (Fig. 3). Anal lobe reduced. VR 1.06-1.13, 1.07. Costal extension 45-65, 51 μm long. Brachiolum with 1 seta. R with 3-6, 5 setae. Remaining veins bare. Squama with 1-2, 2 setae.

Thorax (Fig. 4). Antepronotum with 2-4, 4 lateral setae. Dorsocentrals 5-7, 6; acrostichals 9-13, 11; prealars 2-3, 3. Scutellum with 2-4, 4 setae. Humeral pit moderately large, ovoid.

Legs. Spur of fore tibia 23-40, 35 μm long; spurs of mid tibia 13-25, 15 μm and 10-18, 12 μm long; spurs of hind tibia 38-50, 41 μm and 10-20, 15 μm long. Hind tibial comb with 9-12, 10 spines, 20-48, 31μm long. Width at apex of fore tibia 35-45, 41 mm, of mid tibia 33-45, 41 mm, of hind tibia 30-45, 38 mm. Lengths (in μm) and proportions of legs as in Table 1.

Hypopygium (Figs 5-6). Anal point tapering to apex, 33-41, 37 μm long, 25-50, 37 μm wide in base, with 3-4, 4 lateral setae in each side. Laterosernite IX with 1-3, 2 setae. Phallapodeme 35-68, 55 μm long. Transverse sternapodeme 35-88, 59 μm long. Gonocoxite 138-191, 157 μm long. Superior volsella triangular, 20-40, 31 μm long, with 5-8, 7 setae. Gonostylus 60-75, 66 μm long. Megaseta 9-13, 11 μm long. Crista dorsalis tooth-shaped. HR 2.11-2.60, 2.38. HV 2.59-3.60, 3.31.

Type material.

Holotype: ♂ (BDN. C11A32), China, Zhejiang Province, Yueqing City, Lingdi County, Jiulong Village, 28°31'00"N, 120°96'00"E, 18.iv.2011, sweeping, Lin XL. Paratypes (11): 4♂♂, as holotype; 6♂♂, Hubei Province, Hefeng County, 29°91'00"N, 110°03'00"E, 16.vii.1999, light trap, Ji BC; 1♂, Jiangxi Province, Wuyi Mountain National Nature Reserve, 27°48'11"N, 117°39'30"E, 13.vi.2004, light trap, Yan CC.

Etymology.

The specific name is an adjective, from Latin brochus, meaning tooth, referring to tooth-shaped crista dorsalis.

Remarks.

The new species resembles Rheocricotopus (Psilocricotopus) bifasciatus Wang & Zheng, 1991 and Rheocricotopus (Psilocricotopus) insularis Makarchenko & Makarchenko, 2005 in the following combination of characters: anal point long, pointed distally; wing anal lobe reduced; crista dorsalis tooth-shaped. But the new species can be separated from the latter species in the basis following combination of characters in Table 2.

Female and immature stages unknown.