Hercostumus singaporensis, Zhang & Yang & Grootaert, 2008

Zhang, Lili, Yang, Ding & Grootaert, Patrick, 2008, Mangrove Hercostomus Sensu Lato (Diptera: Dolichopodidae) Of Singapore, Raffles Bulletin of Zoology 56 (1), pp. 17-28 : 19-21

Hercostumus singaporensis , new species

( Figs. 4–10 )

Material examined. – Holotype. Male : SINGAPORE: Sungei Buloh, 22 Jun.2005, sweeping in mangrove (25122, coll. PG, det. LZ, Si800, ZRC).

Diagnosis. – First flagellomere 1.6 times as long as wide; arista with basal segment 0.3 times as long as apical segment. Femora wholly yellow. Fore tibia apically with 2 long black posterior bristles (longer than tarsomere 1); mid tibia concave ventrally on apical half. Fore tarsomere 1 shortened, concave ventrally with 2 long curved ventral bristles; mid tarsomere 1 concave ventrally, with 1 strong ventral bristle near middle and 5 ventral bristles basally. CuAx ratio 1.3.

THE RAFFLES BULLETIN OF ZOOLOGY 2008

Description. – Male. Body length 2.8 mm, wing length 2.3 mm.

Head metallic green with pale grey pollen. Face narrowing downward, distinctly narrower than first flagellomere. Hairs and bristles black. Antenna ( Fig. 5 ) blackish-brown, first flagellomere 1.6 times as long as wide; arista minutely pubescent with basal segment 0.3 times as long as apical segment. Proboscis blackish brown with black hairs; palpus black with black hairs and black apical bristles.

Thorax metallic green with pale grey pollen. Hairs and bristles black. Five strong dc, 5 pairs of acr; scutellum with two pairs of bristles (basal pair short and weak). Propleuron with 1 black bristle on lower part. Legs yellow [hind tarsomeres 4–5 broken off], fore coxa yellow, mid coxa blackish, hind coxa dark yellow with 1 black outer spot. Mid tarsomeres 3– 5 brownish, apex of hind tibia and entire hind tarsus brownish to brown. Hairs and bristles black. Mid and hind coxae each with 1 exterior bristle. Mid and hind femora each with 1 preapical bristle. Fore tibia with 1 ad and 2 pd, apically with 2 short bristles and 2 long black posterior bristles (longer than tarsomere 1); mid tibia concave ventrally on apical half, with 2 ad, 2 pd, 1 av and 8 thin vs. on basal half, apically with 4 bristles and 2 longer posterior bristles; hind tibia with 3 ad, 3 pd and 2 av, apically with 3 bristles. Fore tarsomere 1 ( Fig. 6 ) shortened, concave ventrally with 2 long curved vs.; mid tarsomere 1 ( Fig. 7 ) concave ventrally, with 1 strong vs. near middle and 5 vs. basally. Relative lengths of tibia and 5 tarsomeres LI 0.85: 0.38: 0.25: 0.2: 0.15: 0.16; LII 1.0: 0.6: 0.45: 0.3: 0.2: 0.2; LIII 1.75: 0.5: 0.7: 0.55:?:?. Wing ( Fig. 4 ) hyaline, tinged with greyish; veins black, R 4+5 and M parallel apically. CuAx ratio 1.3. Squama yellow with pale hairs. Halter yellow.

Abdomen metallic green with pale grey pollen. Hairs and bristles black. Male genitalia ( Figs. 8–10 ): Epandrium elongated, distinctly longer than wide; lateral lobe long fingerlike, furcate apically with 3 bristles; cercus large, with short apical tail; hypandrium obtuse apically.

Female. Unknown.

Etymology. – The name refers to the type locality Singapore.

Distribution. – Singapore.

Remarks. – Hercostomus singaporensis , new species, can be distinguished from all other known species by its shortened fore tarsomere 1 being concave ventrally bearing 2 long curved ventral bristles. Mid tarsomere 1 is also concave ventrally.

Figures

Figs. 4–10. Hercostomus singaporensis, new species, male: 4, wing; 5, antenna; 6, apex of fore tibia and tarsomere 1 (anterior lateral view); 7, apex of mid tibia and tarsomere 1 (posterior view); 8, male genitalia; 9, cercus; 10, surstyli.