Systenus latimaculatus, Lin & Zhang & Yang, 2023

Lin, Chen, Zhang, Chunmin & Yang, Ding, 2023, The genus Systenus Meigen, 1803 (Diptera: Dolichopodidae) from Yunnan, China, with descriptions of six new species, Zootaxa 5383 (2), pp. 153-166 : 163

7. Systenus latimaculatus sp. nov.

( Figs 6 , 17–18)

Diagnosis. Postpedicel 3.2 times longer than wide. Wing with wide grayish brown apical band. R 4+5 and M 1 parallel apically. Fore coxa yellow, mid and hind coxae dark brown. Hind femur narrowly brown near extreme tip. Mid tibia brown at narrow tip, hind tibia dark brown at apical 1/3. Abdominal segment 7 petiolate. Surstylus large and broad, apically distinctly widened, and with a long finger-like dorsal process directed inward.

Description. Male ( Fig. 6 ). Body length 3.25 mm, wing length 3.13 mm.

Head metallic green with pale gray pollinosity. Frons metallic green with white gray pollinosity; face dark metallic green with dense silvery white pollinosity, slightly wider than width of postpedicel. Hairs and bristles on head black, but lower postocular bristles yellowish. 2 oc, 2 vt, 2 pvt. Antenna [apical segment of arista broken] black; pedicel with blackish apical bristles; postpedicel 3.2 times longer than wide, basally rather thick, apically long finger-like, and with dense dark brown pubescence; arista apical (Fig. 17). Proboscis short, dark brown with short blackish hairs; palpus small, blackish, with black hairs and 1 slightly long black apical bristle.

Thorax metallic green with pale gray pollinosity. Hairs and bristles on thorax black; 6 dc, 13–14 irregularly paired acr; 2 strong npl, 1 strong sa, 2 strong pa; sc long and strong, lsc short and hair-like. Propleuron with 1 brown bristle on lower portion.

Legs [mid and hind tarsi broken] mainly yellow; fore coxa yellow, mid and hind coxae dark brown; hind femur narrowly brown near extreme tip; mid tibia brown at narrow tip, hind tibia dark brown at apical 1/3; fore tarsomere 5 brown. Hairs and bristles on legs black except those on coxae yellow. Mid tibia with 1 ad. Relative length of tibiae and five tarsomeres of legs LI: 4.2: 1.9: 1.7: 1.0: 0.6: 0.4; LII: 5.7: distal podomeres missing; LIII: 6.9: distal podomeres missing.

Wing nearly hyaline with wide grayish brown apical band; veins dark brown, R 4+5 and M 1 distinctly separated and parallel apically; CuAx ratio 0.5. Squama yellow, with fan of pale white hairs. Halter pale yellow.

Abdomen dark metallic green with pale gray pollinosity. Hairs and bristles on abdomen black. Abdominal segment 7 petiolate.

Male genitalia (Fig. 18): epandrium distinctly longer than wide; epandrial lobe basally thick, distinctly narrowed toward tip, short hook-like at extreme tip; surstylus large and broad, apically distinctly widened with nearly truncate apical margin, and with long finger-like dorsal process directed inward. Cercus basally rather wide, apically finger-like. Hypandrium long spine-like, slightly curved. Pallus long and thin.

Female. Unknown.

Type material. HOLOTYPE ♂, China: Yunnan, Lvchun, Yakou, Shuikuxiafang [23°3’25.2”N, 102°46’37.71”E, 1779 m], collected by Malaise trap, 2019.IV.19–V.19, Liang Wang and Xin Li ( CAU).

Distribution. China (Yunnan).

Remarks. Systenus latimaculatus sp. nov. is peculiar and can be easily separated from other Asian known species of the genus by the following features: pregenital segments petiolate; wing with wide grayish brown apical band; R 4+5 and M 1 parallel apically ( Olejnícek and Kozánek, 1997; Lin & Yang, 2022).

Etymology. The specific name refers to the wide apical spot of the wing.

Figures

FIGURES 1–6. 1. Systenus apicidigitatus sp. nov.; 2. Systenus basiflavus sp. nov.; 3. Systenus digitatus sp. nov.; 4. Systenus flavilateralis sp. nov.; 5. Systenus huanglianus sp. nov.; 6. Systenus latimaculatus sp. nov. All male. Scale bar =1.0mm.