Rhaphium gangchanum, Qilemoge,, Wang, Mengqing & Yang, Ding, 2019

Qilemoge,, Wang, Mengqing & Yang, Ding, 2019, Three new species of Rhaphium from China, with an updated key to Chinese Rhaphium (Diptera, Dolichopodidae, Rhaphiinae), ZooKeys 840, pp. 87-99 : 87

Rhaphium gangchanum sp. n. Figures 1, 4, 5

Diagnosis.

First flagellomere about 2.2 times longer than wide; arista with basal segment 0.1 times as long as apical segment. All postocular bristles black. All coxae and femora black; fore tibia mainly yellow, black dorsally, mid tibia yellow, hind tibia mainly black, yellow at middle dorsally; fore tarsomere 1 inflated apically. Fore and mid coxae with black bristles, mid coxa apically with a bunch of black bristles, hind coxa with one black outer bristle. CuAx ratio 0.5. Surstylus short and thick, nearly square, with one apical protuberance. Cercus bifoliate, outer lobe and inner lobe strip-like, inner lobe 1/4 as long as outer lobe, apically with strong bristles.

Description.

Male (Fig. 1). Body length 4.8 mm. Wing length 4.2 mm.

Head metallic green with pale gray pruinescence. Frons with white pruinescence. Face black with pale pruinescence, not as wide as first flagellomere (length). All postocular bristles black. Two oc, two vt, two pvt. Antenna (Fig. 4) black; first flagellomere elongated, about 2.2 times longer than wide, apically sharp; arista black, apical position, basal segment 0.1 times as long as apical segment. Proboscis black with black hairs, palpus black with black apical bristle and hairs.

Thorax metallic green with pale gray pruinescence. Mesonotum without dark spot. Hairs and bristles on thorax black. Five strong dc, four irregular pairs of acr, two strong npl, one strong sa, two strong pa; scutellum with two pairs of sc, medial pair pubescent, lateral pair strong.

Legs black, all coxae and femora black; fore tibia mainly yellow, black dorsally, mid tibia yellow, hind tibia mainly black,yellow dorsally at middle; fore tarsomere 1 inflated apically, fore and mid tarsi black from tip of tarsomere 2 onwards, hind tarsus entirely black. Hairs and bristles on legs black. Fore and mid coxae with bristles, mid coxa apically with a bunch of bristles, hind coxa with one outer bristle. All femora with ventral bristles, mid and hind femora each with one preapical bristle. Fore tibia with five ad, six pd, and four apical bristles, av absent,; mid tibia with two ad, five pd, three av, and four apical bristles; hind tibia with three ad, five pd, three av, and three apical bristles. Relative lengths of tibia and 5 tarsomeres of fore leg 2.5: 1.2: 0.7: 0.4: 0.3: 0.4; mid leg 3.2: 1.7: 0.8: 0.6: 0.5: 0.4; hind leg 4.3: 1.3: 1.2: 0.8: 0.5: 0.4. Wing hyaline, veins black; M bent medially, M and R4+5 parallel apically; CuAx ratio 0.5. Squama yellow with yellow hairs. Halter yellow.

Abdomen entirely metallic green with pale gray pruinescence. Hairs and bristles on abdomen black. Male genitalia (Fig. 5): epandrium black, nearly as long as wide. Surstylus black, short and thick, nearly square, with one apical protuberance. Cercus yellow, bifoliate, outer lobe and inner lobe strip-like, inner lobe 1/4 as long as outer lobe, both lobes with short bristles.

Female. Unknown.

Types.

Holotype male, CHINA, Qinghai, Gangchaxian, Shaliuhe, 3,200 m; collected by sweep net in grassland, 2015.VIII.06, leg. Liang Wang. Paratypes: one male, same data as holotype.

Distribution.

Palaearctic: China (Qinghai).

Remarks.

The new species is somewhat similar to R. heilongjiangense Wang, Yang & Masunaga, 2005, but the two species can be separated by several features. In R. gangchanum , all postocular bristles are black, the thorax has five dc, and the mid femur is black (Fig. 1), the cercus is bifoliate (Fig. 5). In R. heilongjiangense , the middle and lower postocular bristles are yellow, the thorax has eight dc, the mid femur is yellow, the cercus is not bifoliate ( Yang et al. 2011: 1255, fig. 804).

Etymology.

The specific name refers to the type locality, Gangcha.