Rhaphium apophysatum, Tang, Chufei, Wang, Ning & Yang, Ding, 2016

Tang, Chufei, Wang, Ning & Yang, Ding, 2016, Rhaphium (Diptera: Dolichopodidae: Rhaphiinae) from China with six new species, Zootaxa 4162 (3), pp. 581-593 : 583-586

Rhaphium apophysatum sp. nov.

( Figs 1 , 7–8 )

Diagnosis. First flagellomere 1.5 times longer than wide; arista 2.8 times longer than first flagellomere ( Fig. 7 ); fore femur with 2 rows of long pale yellow bristles longer than width of fore femur; cercus very long, wide at basal half ( Fig. 8 ).

Description. Male ( Fig. 1 ). Body length 4.2 mm, wing length 3.5 mm. Head: Frons metallic green; face dark metallic green with thick silvery white pollinosity; palpus and proboscis black, palpus with 5 black bristles on tip, proboscis very short, with pale hairs; antenna black; scape almost bare; pedicel with 1 long strong bristle and 3 short bristles dorsally, 1 long strong bristle ventrally; first flagellomere nearly isosceles triangular, blunt at tip, 1.5 times longer than wide; arista apical, simple, with microscopic hairs, arista 2.8 times longer than first flagellomere ( Fig. 7 ); postocular bristles dorsally long black in single row, ventrally in 3 rows, of which inner row black, 2 outer rows pale. Thorax metallic green; hairs and bristles black; 5 dc, of which 4th pair located inwards; 4 irregular pairs of long thin acr; median sc strong, lateral sc weak as side hairs. Legs mainly yellow, but coxae dark metallic green, fore femur, apical 1/3 of mid femur, apical 1/3 of hind femur and tarsi black; hairs and bristles on legs mainly black. Fore and mid coxae anteriorly with rows of irregular black hairs; fore coxa with 4 anterior bristles at apical 1/3, mid coxa with 2 black anterior bristles at apical half, hind coxa with 1 black outer bristle at middle; fore and mid trochanters black, hind trochanter yellow; fore femur dark metallic green, with 1 weak preapical ad and 2 rows of long pale yellow ventral bristles longer than width of fore femur; mid femur mainly black except yellow tip, with 2 preapical av and 1 row of long pale ventral hairs at apical quarter to half, apically with 1 short bristle; hind femur yellow except black apical quarter, with 3 weak ad near base; tibiae yellow except brown tip of hind tibia; fore and mid tarsi dark yellow to dark brown onward, hind tarsus entirely black; fore tibia with 3 weak offset ad/pd, apically with 3 short bristles; mid tibia with 4 ad, 4 pd (1 short preapical), 2 short av (1 preapical), apically with 1 short bristle; hind tibia with 3 ad, 2 pd, apically with 3 bristles. Fore basitarsus with 1 row of strong short av; mid basitarsus with 3 pd, of which 1st very long. Relative length ratio from tibia to tarsomere 5: LI: 4.0/2.0/1.0/0.6/0.4/ 0.4, LII: 5.0/3.6/1.4/1.0/0.6/0.4, LIII: 7.2/2.4/2.4/1.6/1.0/0.8. Wing hyaline, somewhat brownish; veins dark brown, R4+5 and M somewhat convergent apically; CuAx ratio 0.67. Squama yellow, with fan of pale white bristles; halter pale. Abdomen: Dark metallic green, hairs pale, bristles black. Hairs on sternite 3 long and strong. 5th segment ventrally expanded to form hood for male genitalia. Male genitalia ( Fig. 8 ): black except cercus brown. Epandrium nearly as long as wide. Surstylus very wide, with several short digitations, each with 1 short hair apically. Cercus very long, distinctly longer than epandrium, wide at basal half. Hypandrium very short, hidden in epandrium in lateral view. Phallus dark and thin. Female. Unknown.

Type material. HOLOTYPE, Ƌ labeled: China: Tibet, Lhasa, Academy of Agricultural Sciences' ecology (N29°64′43″ E91°03′74″), 3650 m, collected by the Malaise trap set near swamp, 2014. IX.1–30, B. Wang & Y. Zhang ( CAU) . PARATYPES: 8 Ƌ, same data as holotype ( CAU) .

Distribution. Oriental: China (Tibet).

Remarks. The new species is similar to R. riparium (Meigen, 1824) widely distributed in the Palaearctic, but may be separated from the latter by the length / width ratio of the first flagellomere and the length ratio of the arista and the first flagellomere, the ventral bristles on the fore femur as well as the shape of the cercus. In R. riparium , the first flagellomere is 2.1 times longer than wide; the arista is 1.9 times longer than the first flagellomere; the fore femur only has 1 row of long pale yellow ventral bristles which is as long as width of the fore femur; the cercus is wide but narrow at base and wider onwards with the distinct marginal denticles ( Yang et al. 2011).

Etymology. The word ‘ apophysatum’ means inflated at base. The species is named for the shape of cercus.

Figures

FIGURE 1 – 6. 1. Rhaphium apophysatum sp. nov.; 2. R. bilobum sp. nov.; 3. R. bisectum sp. nov.; 4. R. daqinggouense sp. nov.; 5. R. dorsiseta sp. nov.; 6. R. neimengense sp. nov. All male. Scale bar = 1.0 mm.

FIGURES 7 – 8. Rhaphium apophysatum sp. nov., male. 7. Antenna, scale bar = 0.2 mm; 8. Male genitalia, lateral view, scale bar = 0.2 mm. Abbreviations: hyp = hypandrium, ph = phallus, sur = surstylus, cer = cercus.