Sinosciapus from Taiwan with description of a new species (Diptera, Dolichopodidae)

Abstract Sinosciapus liuae sp. n. is newly described from Taiwan. The genus Sinosciapus is discussed and a key to the three known Oriental species is provided.


Introduction
Sinosciapus Yang, 2001 is a small genus of the family Dolichopodidae with only two previously known Oriental species from Southwest China and South China (Yang et al. 2006;Yang et al. 2011). The genus is characterized by the following features: eyes in both sexes narrowly separated; vertex in both sexes with strong vertical bristle; arista subapical, slightly shorter than width of head; lateral scutellar bristle strong, about 2/3 as long as apical one; fore tarsomere 5 with an elongated spine-like claw (Yang 2001;Yang et al. 2011).
In the present paper, the genus Sinosciapus is newly recorded from Taiwan with one new species, based on specimens collected by Ms. Xiaoyan Liu in Taiwan in 2011. An updated key to the three known species of Sinosciapus is given.

Genus
Diagnosis. Eyes in both sexes narrowly separated, frons and face rather narrow (face less than 1/2 as wide as one eye, frons narrower than one eye). Vt strong. Clypeus apically separated from inner margin of eyes. Cheeks of females posteriorly with 1 black spine-like bristle. First flagellomere subtrapezoid or semicircular; arista subapical, slightly shorter than width of head. 5 strong dc, anterior 3 dc somewhat shorter; 5-7 irregularly paired acr very short and hair-like; scutellum with two pairs of strong sc, basal pair 2/3 as long as apical pair. Fore coxa with 3 bristles in male, with 3-4 spine-like bristles and many short spine-like bristles on inner surface in female. Wing: m-cu straight. Male genitalia rather small with well developed cercus like in Condylostylus.

Remarks.
Sinosciapus is an Asian genus, with three known species from subtropical or tropical forests of Southwest China and South China (Fig. 5). It is similar to Amblypsilopus in following points: arista rather short, shorter than head width; tibial chaetotaxy often weak, especially in males; m-cu usually straight. But it can be separated from the latter by the following features: eyes in both sexes narrowly separated, frons and face rather narrow (frons narrower than one eye); both sexes with strong vt; lateral sc strong, about 2/3 as long as apical one; fore tarsomere 5 with 1 elongated spine-like claw. In Amblypsilopus, the eyes in both sexes are widely separated, the frons and face are rather wide (frons wider than one eye), the male vertex has vt weak or lost; the lateral sc is always reduced to the weak hairs or lost; the claws on fore tarsomere 5 are normal (Bickel 1994;Yang et al. 2011). Remarks. This species is easily separated from S. tianmushanus Yang by the thorax and abdomen being mostly metallic green, and first flagellomere as long as wide and semicircular.
Description. Male. Body length 3.0-3.7 mm, wing length 3.6-3.7 mm. Head metallic green except clypeus dark yellow, with pale gray pollen. Hairs and bristles on head black, except middle and lower postoculars (including postero-ventral hairs) pale yellow. Ocellar tubercle distinct, with pair of long oc and 2 very short posterior hairs. 1 vt on slope shorter than oc; 1 pvt at the end of postoculars row nearly as long as vt. Antenna yellow except first flagellomere dark yellow; first flagellomere nearly trapezoid in lateral view, as long as wide; arista subapical, blackish with blackish pubescence, shorter than head width. Palpus yellow, with pale hairs and 1 blackish apical bristle. Proboscis yellow, with short pale hairs.
Abdomen partly metallic green with pale gray pollen, except tergites 2-5 with anterior and lateral portions yellow, sternites 1-5 yellow except posterior margin of sternite 5 brown. Hairs and bristles on abdomen black and weak, but hairs on sternites 1-5 pale yellow. Hypopygium black except cerci and hypandrium brownish.
Male genitalia (Figs. 2-3). Epandrium somewhat quadrate, nearly as long as wide, and with oblique apical margin and upper apical corner acute in lateral view. Surstylus short and wide with 2 long bristles. Cercus very long, about 4 times as long as epandrium, basally very thick, apically long finger-like, slightly curved. Hypandrium long conical. Phallus with short thick apical portion slightly narrowed toward extreme tip in ventral view. Female. Body length 3.3-5.0 mm, wing length 3.6-4.4 mm. Similar to male, but different in following points: mesonotum yellow with a large metallic green midposterior spot nearly triangular and two small pale metallic green lateral spots nearly semicircular. Mid coxa with a brown outer stripe. Fore coxa with 4 long spine-like apical bristles and several very short spine-like anterior bristles. Abdominal tergite 1 also yellow except posterior margin metallic green. Legs with only tarsomere 5 short. Relative length ratio of tibiae and tarsomeres: LI 5.8 : 5.1 : 1.7 : 1.2 : 0.8 : 0.55; LII 7.9 : 6.8 : 1  Yang et Saigusa, 2001 in having the first flagellomere as long as wide and epandrium with the oblique apical margin in lateral view. But it can be separated from the latter in the following features: thorax and abdomen mostly yellow, first flagelloemre nearly trapezoid, cercus weakly curved, epandrium with upper apical corner acute in lateral view; in Sinosciapus yunlonganus, thorax and abdomen mostly metallic green, first flagellomere semicircular, cercus distinctly curved, epandrium with lower apical corner acute in lateral view (Yang and Saigusa 2001;Yang et al. 2001).