Stilpon weilingae, Grootaert & Shamshev, 2012

Grootaert, Patrick & Shamshev, Igor V., 2012, The fast-running flies (Diptera, Hybotidae, Tachydromiinae) of Singapore and adjacent regions, European Journal of Taxonomy 5, pp. 1-162 : 140-142

Stilpon weilingae sp. nov.

Figs 232-235

Diagnosis

Species with yellow thorax, scutum with brownish yellow patch above wing base; legs entirely yellow; wing distinctly maculate, broadly brownish infuscate along R 2+3 and CuA 1 (except subapical part), halter with black knob.

Description

Male LENGTH. Body 1.2 mm, wing 1.1 mm.

HEAD. Black. Two short fine vertical bristles present. Frons linear with sides nearly parallel, broad, entirely tomentose. Ocellar tubercle with minute setulae. Antenna with scape and pedicel yellowish brown, postpedicel yellow. Palpus yellow, with moderately long, yellowish subapical bristle.

THORAX. Yellow in ground-colour; scutum with indistinct brownish yellow patch above wing base, metanotum brownish yellow medially, sutures brownish in various extents. Postpronotal bristle minute. Acrostichals arranged in 2 irregular rows, hardly separated from dorsocentrals, complete posteriorly; dorsocentrals multiserial, more numerous anteriorly, uniform, complete posteriorly.

LEGS. Entirely yellow. Coxae with unmodified setation; hind trochanter lacking spinules. Fore femur markedly thickened, with row of moderately long yellowish anteroventral and row of minute posteroventral bristles. Fore tibia spindle-like, with unmodified setation. Mid femur slender, with 4 moderately long ventral bristles basally and 1 long, subapical bristle anteriorly. Mid tibia lacking ventral spinules and prominent bristles. Hind femur (viewed laterally) evenly thickened towards middle, with 1 complete row of short anteroventral bristles (longer subapically). Hind tibia unmodified, with unmodified posterior apical comb. Fore and mid tarsi slender, hind tarsomere 1 slightly thickened.

WING. Normally developed, covered with uniform microtrichia; distinctly maculate, broadly brownish infuscate along R 2+3 and CuA 1 (except subapical part). Costal vein with short setulae along anterior margin. R 1 (especially in meeting point with costa), R 2+3 and M 1+2 thickened. R 2+3 rather short, nearly 1.5 times as long as Rs, straight, meeting costa near wing midway. Distance between apices of R 2+3 and R 4+5 nearly 4.0 times longer than distance between apices of R 1 and R 2+3. R 4+5 evenly curved toward costa in apical part. R 4+5 and M 1+2 slightly divergent before wing apex. Halter with deep black knob and yellow stem.

ABDOMEN. Tergite 1 pale yellow, remaining tergites brownish; tergites 1-2 unmodified. Segment 8 with 2 long and several short setae. Sternites brownish yellow, with scattered minute brownish setulae, sternites 2-5 divided along midline. Tergites 2-6 with darker lateral patches covered with microtrichia.

TERMINALIA. Dark brown ( Figs 232-235 ). Cerci narrowly fused, short, lacking spines; right cercus slightly prominent, with several setae of different lengths; left cercus unbranched, short, broadened apically, with several short setae. Epandrium completely divided. Right surstylus ( Fig. 232 ), with several long

setae dorsally, lacking spines, prolonged into narrow lobe on each apical corner. Left epandrial lamella fused to hypandrium, with 1 minute setula in apical part. Left surstylus with upper lobe divided; lower part lacking surstylar comb, upper part subglobular ( Fig. 234 ), with 1 minute setula. Hypandrium with 2 long setae apically. Phallus short.

Female

Unknown.

Material examined

Holotype ♂ SINGAPORE: Mandai (MAN01), 12 May 2009, mangrove, Mal. (reg. 29056, leg. P.G.; in ZRC).

Etymology

The species is dedicated to Ms. Wei Ling Lim for her very enthusiastic help during the fieldwork.

Distribution

Singapore.

Habitat and seasonal occurrence

This species was collected in mangrove, with a single record from May.

Remarks

The new species is similar to S. laawae , which is known from Thailand and Singapore. The main differences between these species are listed in the key.

Figures

Figs 232-235. Stilpon weilingae sp. nov., ♂. 232. right surstylus, lateral view. 233. epandrium with cerci, dorsal view. 234. left surstylus, lateral view. 235. right epandrial lamella.