Systenus flavilateralis, 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 : 160

4. Systenus flavilateralis sp. nov.

( Figs 4 , 13, 14)

Diagnosis. Thoracic pleura mostly dark yellow. Abdomen mostly dark yellow. Antennal scape and pedicel and base of postpedicel yellow to dark yellow. Postpedicel rather short, subconical, 2.0 times longer than wide; arista subapical. All coxae yellow. Hind femur dark brown at apical 1/3; tibia brown to dark brown except extreme base and tip; tarsus dark brown. Surstylus short and thick with two small outer apical processes. Male cercus bifurcated apically.

Description. Male ( Fig. 4 ). Body length 2.6 mm, wing length 2.25 mm.

Head metallic green with pale gray pollinosity. Frons metallic green with white gray pollinosity; face dark metallic green with dense silvery white pollinosity, nearly as wide as postpedicel. Hairs and bristles on head black, but postocular bristles yellowish. 2 oc, 2 vt, 2 pvt. Antenna [aristal apical segment broken] dark brown, but scape and pedicel yellow and postpedicel dark yellow at base; pedicel with black apical bristles; postpedicel rather short, subconical, 2.0 times longer than wide, with dense pale pubescence (Fig. 13). Proboscis short, dark brown with blackish hairs; palpus small, blackish, with black hairs and 1 black apical bristle.

Thorax metallic green with pale gray pollinosity, but humerus brownish yellow; pleura mostly dark yellow except mesopleuron mostly blackish, pteropleuron with black spot, sternopleuron blackish at posterior margin and hypopleuron blackish anteriorly. Hairs and bristles on thorax black; 6 dc; 8 to 9 irregular pairs of acr; 2 strong npl, 1 strong sa, 2 strong pa; sc long and strong, lsc short and hair-like.

Legs [hind tarsomeres 4–5 broken] mainly yellow; all coxae yellow; hind femur dark brown at apical 1/3; hind tibia brown to dark brown except extreme base and tip; mid tarsus brownish yellow, hind tarsus dark brown. Hairs and bristles on legs black. Hind coxa with 1 strong outer bristle basally. Mid tibia with 2 ad, 2 pd, 3 pv and 4 apical bristles; hind tibia with 2 ad and 4 apical bristles. Mid and hind tarsomeres 1–4 each with 4 short apical bristles. Relative length of tibiae and five tarsomeres of legs LI 3.0: 1.8: 1.0: 0.9: 0.6: 0.5; LII 4.4: 2.3: 1.3: 1.0: 0.7: 0.5; LIII 5.4: 1.4: 1.7: 1.0: distal tarsomeres missing.

Wing hyaline, weakly tinged brownish; veins dark brown; M 1 bent medially, R 4+5 and M 1 distinctly convergent apically; CuAx ratio 0.6. Squama yellow with blackish hairs. Halter pale yellow.

Abdomen mostly dark yellow with pale gray pollinosity. Terga 1–3 dark yellow except tergum 3 pale metallic green at middle; terga 4–6 dark metallic green; venter dark yellow. Hairs and bristles on abdomen black. First tergum with very long black hairs at posterior margin.

Male genitalia (Fig. 14): epandrium distinctly longer than wide; epandrial lobe long and thick, apically distinctly narrowed toward tip; surstylus short and thick with two small outer apical processes. Cercus long and thick, apically bifurcated. Hypandrium long, somewhat thick, apically narrow and slightly curved. Phallus long and very thin.

Female. Body length 2.45 mm, wing length 2.4 mm. Similar to male.

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) . PARATYPE: 1 ♀, same data as holotype ( CAU) .

Distribution. China (Yunnan).

Remarks. Systenus flavilateralis sp. nov. here is somewhat similar to S. Tenorio Bickel, 2015 from Costa Rica in having the short thick postpedicel and subapical arista.

Etymology. The specific name refers to the thoracic pleura mostly dark yellow.

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.