Teuchophorus stenostigma Meuffels & Grootaert, 2003, 2004

Grootaert, Patrick, 2006, The Genus Teuchophorus (Diptera: Dolichopodidae) In Singapore, Raffles Bulletin of Zoology 54 (1), pp. 59-82 : 79-80

Teuchophorus stenostigma Meuffels & Grootaert, 2003

( Figs. 50-55 )

Material examined. – SINGAPORE: 3 males, 2 females, Nee Soon , Central Catchment area, acidic swamp forest, 4 Dec.2002 (22054, coll. P. Grootaert, Si 320, Si 444) ; 1 female, Nee Soon , 9 Mar.2005, (25005, coll. P. Grootaert Si 513) ; 1 male, 1 female, Bukit Timah , 16 Mar.2005 (25021, coll. P. Grootaert, Si 514) ; 3 males, 1 female, Sime forest , 14 Mar.2005 (25013, coll. P. Grootaert, Si 420) ; 5 males, 3 females, Sime forest , 1 Apr.2005 (25041, coll. P. Grootaert, Si 638) ; 1 male, 2 females, Sime forest , 8 Apr.2005 (25044, coll. P. Grootaert, Si 690) ; 1 male, Sime forest , 2 Jul.2005 (25191, coll. P. Grootaert, Si 867) .

MALAYSIA: 12 males, Pulau Tioman, Juara , 20 Jul.2005 (24246, coll. P. Grootaert, Tio 127) ; 5 males, Johor, Gunung Belumut , 22 Oct.2005 (25397, coll. P. Grootaert, Si 1099) .

Diagnosis. – Third antennal segment as long as wide. Wing with a very narrow stigma i.e. costa a little thickened and slightly darkened. Acr uniseriate. Fore metatarsus with a distinct small ventral spinule at base (also in female). Mid femur with only minute ventral bristles. Mid tibia on apical third without a ventral row of spinules nor a serration. Hind femur with very short ventral bristles, some longer av preapicals. Halter dark. Aedeagus not large nor contrastingly black like in T. limosus .

Description. – Male. Body length: 1.37-1.55 mm; wing length: 1.32-1.5 mm.

Head. Frons and face with shining dark metallic green ground-colour. Face about 3/4 times as wide as width of third antennal segment. Palpus small, black, with a small, black apical bristle. Rostrum brown. Occiput blackish green. Chaetotaxy as usual; no postocellars. Postoculars uniseriate, short, black. Antenna ( Fig. 50 ) brown; third segment rounded triangular, with downward shifted blunt apex, a little longer than wide. Arista about 3 times as long as antenna, shortly pubescent; basal aristal segment slightly more than half as long as third antennal segment.

Thorax. Mesoscutum dark brown, paler at sides, but darker toward tip; scutellum blackish. Pleurae largely yellowish brown. Chaetotaxy as usual; acr uniseriate, moderately long. Legs and coxae yellow, but apical 3/4 of hind femora, hind tibiae and tarsi brown.

Fore leg. Coxa anteriorly with very short black hairs, that become longer towards apex of coxa. Femur without bristles. Tibia slightly shorter than femur, without bristles or serration. First tarsal segment ventrally shortly spinulose, and with a small black spinule at ventral base. Length of femur, tibia and tarsal segments (in mm): 0.35: 0.37: 0.21: 0.08: 0.07: 0.06: 0.07.

Mid leg. Coxa anteriorly with very short brown hairs. Femur with about 4 ventral bristles at basal third being _ of width of femur ( Fig. 52 ); a weak preapical pv, and a yet thinner preapical av. Tibia 2 ad, 1 pd, 1 av, all strong. Length of femur, tibia and tarsal segments (in mm): 0.56: 0.52: 0.21: 0.12: 0.07: 0.07: 0.07.

Hind leg. Coxa with a thin, black exterior bristle. Femur ( Fig. 53 ) with a short preapical av, and some of the hairs of the anteroventral row near tip very slightly lengthened. Tibia about as long as femur; 3 dorsal bristles; 1 very short and weak ventral bristle. Length of tibia and tarsal segments (in mm): 0.56: 0.56: 0.14: 0.17: 0.11: 0.08: 0.07: 0.07.

Wing ( Fig. 51 ) brownish tinged, with dark brown veins. A narrow, lanceolate, brownish stigma, occupying less than half the width of subcostal cell. r4+5 and m1+2 very slightly diverging. Vein Cu black, at least darker than the other veins. Halter somewhat brownish (rather dark in some specimens). Squama brown, with a blackish border, and 4 long black cilia. Abdomen dorsally dark brown or brown, with a feeble greenish gloss. Sterna brown. Hairs and hindmarginal bristlets on terga short, black. Hypopygium ( Fig. 54-55 ) brown, with tips of surstyli black.

Female. Body length: 1.55 mm; wing length: 1.5 mm

In most respects identical to male. Face hardly broader than in male. Wing without stigma, but costa slightly thickened. Oviscapt with a row of short black acanthae.

Discussion. – Teuchophorus stenostigma is the only Singaporean species with a slightly developed stigma, the other species have at most the costa a little darkened. T. laosensis Olejnicek, 2003 , is a similar species, but it has brownish black antennae and yellow halters. The hind tibia should bear ventral bristles, but Oleijnicek’s drawing shows a row of long dorsal bristles. Teuchophorus stenostigma from Singapore has brown antennae, darkened halters, hind tibiae without ventral bristles, at most some hairs ventrally and only 3 dorsal bristles. Teuchophorus stenostigma was originally described from South Thailand (Trang province) in a similar habitat as here in Singapore. The original description mentions yellow antenna, yellow halters and largely yellow pleurae. The specimens from Singapore are all darker. The shape of the surstyli is the same, but the bristling on the ventral surstylus is longer in the Singaporean specimens. At the moment we consider them conspecific.

Distribution and habitat. – Thailand, Malaysia, Singapore. River banks in forest.

Figures

Figs. 50-55. Teuchophorus stenostigma, male: 50, antenna; 51, wing; 52, mid leg anteriorly; 53, hind leg anteriorly; 54, hypopygium ventral view; 55, hypopygium lateral view.