Hercostomus brevidigitalis, 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 : 18-19

Hercostomus brevidigitalis , new species

( Figs. 1–3 )

Material examined. – Holotype. Male , SINGAPORE, Sungei Buloh, 18 May 2005, Mal. 1 (25161, coll. PG, det. LZ, Si801, ZRC).

Paratypes. SINGAPORE: Pulau Ubin , Chek Jawa : 1 female, 2 Dec.2003; 1 male, 11 Dec.2003; 1 female, 26 Mar.2005; 2 females, 30 Dec.2005 ( RBINS) . Sungei Buloh, 5 males, 22 Apr.2005; 1 male, 3 females, 27 Apr.2005; 23 males, 5 females, 11 May 2005; 4 males, 6 females, 18 May 2005; 3 males, 2 females, 25 May 2005; 1 male, 9 females, 1 Jun.2005; 3 males, 4 females, 10 Jun.2005 (1 male and 2 females in IOZ) ; 4 females, 15 Jun.2005; 2 males, 2 females, 22 Jun.2005; 3 males, 7 females, 6 Jul.2005; 4 females, 20 Jul.2005; 1 female, 27 Jul.2005; 1 female, 5 Aug.2005; 1 male, 5 Aug.2005; 1 male, 3 females, 26 Aug.2005; 1 male, 4 females, 7 Sep.2005; 3 females, 16 Sep.2005; 1 male, 3 females, 28 Sep.2005; 6 females, 14 Oct.2005; 3 males, 8 females, 28 Oct.2005; 1 female, 9 Nov.2005; 2 males, 3 females, 18 Nov.2005; 1 male, 5 females, 3 Dec.2005; 4 females, 4 Jan.2006.

Semakau Island , 1 female, 26 Jun.2005, sweeping .

Diagnosis. – First flagellomere elongate, 2.3 times as long as wide. All coxae blackish; femora blackish except tip of fore and mid femora. Hind femur with 3 brown ventral bristles near base (a little shorter than width of femur). Fore tarsomere 1 without ventral slit. Squama yellow with black hairs. Male genitalia very long, reaching thorax.

Description. – Male - Body length 3.2–3.6 mm, wing length 3.2–3.5 mm.

Head metallic green with pale grey pollen. Face narrowing downward, distinctly narrower than first flagellomere. Hairs and bristles black. Postocular bristles (including posteroventral hairs) black. Antenna ( Fig. 1 ) blackish brown, first flagellomere elongated, 2.3 times as long as wide; arista apicodorsal, 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, 6 pairs of acr; scutellum with two pairs of bristles (basal pair short and weak). Propleuron with 1 black bristle on lower part. Legs yellow; all coxae blackish; femora blackish except tip of fore and mid femora. Mid and hind tarsi from tip of tarsomere 1 onward brownish. Hairs and

THE RAFFLES BULLETIN OF ZOOLOGY 2008

bristles black. Mid and hind coxae each with 1 exterior bristle. Mid and hind femora each with 1 preapical bristle. Hind femur with 3 brown vs. near base (a little shorter than width of femur). Fore tibia with 2 ad and 1 weak pd, apically with 3 long bristles, the longest 0.8 times as long as tarsomere 1; mid tibia with 3 ad, 2 pd and 1 av, apically with 4 bristles; hind tibia with 3 ad, 3 pd and 1 av, apically with 3 bristles. Fore tarsomere 1 with 2 vs.; hind tarsomere 1 with 1 vs. at base. Relative lengths of tibia and 5 tarsomeres LI 0.8: 0.45: 0.2: 0.2: 0.15: 0.15; LII 1.3: 0.55: 0.3: 0.25: 0.2: 0.15; LIII 1.55: 0.5: 0.55: 0.5: 0.35: 0.2. Wing hyaline, tinged with greyish; veins brown, R 4+5 and M parallel apically, CuAx ratio 0.7. Squama yellow with black hairs. Halter yellow.

Abdomen metallic green with pale grey pollen. Hairs and bristles black. Male genitalia very long, reaching thorax. Epandrium longer than wide ( Figs. 2 ), inner epandrial lobe short digitiform with 3 bristles; cercus triangular with 3 strong, black bristles on outer margin ( Fig. 3 ); hypandrium somewhat acute apically; aedeagus obtuse apically.

Female. Body length 2.3–2.5 mm, wing length 2.1–2.2 mm. Similar to male, except first flagellomere as long as wide;

hind femur without vs. at base and fore tibia without long apical ventral bristles.

Etymology. – The name brevidigitalis refers to the short and digitiform epandrial lobe.

Distribution. – Singapore.

Remarks. – The new species is somewhat similar to H. meieri , new species, in having the first flagellomere elongated, but it has all coxae and femora blackish (except tip of fore and mid femora), and cercus bears 3 strong bristles on outer margin. In H. meieri , new species, fore coxa is yellow, mid and hind coxae are brown and femora are wholly yellow; cercus bears no strong bristles on outer margin.

Figures

Figs. 1–3. Hercostomus brevidigitalis, new species, male: 1, antenna; 2, male genitalia; 3, cercus. iel, inner epandrial lobe.