Stilpon singaporensis

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: 138-140

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Stilpon singaporensis

sp. nov.

Stilpon singaporensis  sp. nov.

Figs 229-231View Figs 229-231


Species with brown thorax; antenna brownish; wing distinctly brownish infuscate, R 4+5 strongly curved towards costa in apical part; abdominal tergites 1 and 2 modified.



LENGTH. Body 1.2 mm, wing length 1.1 mm.

HEAD. Black. Occiput subshining, finely greyish pollinose. Two moderately long vertical bristles present. Frons linear with sides nearly parallel, rather broad, entirely tomentose, subshining. Ocellar tubercle with minute setulae. Antenna brownish (in paler specimens postpedicel somewhat paler). Palpus yellow, with strong, black subapical bristle.

THORAX. Brown. Scutum entirely tomentose. Postpronotal bristle long, inclinate. Dorsocentral bristles in multiple rows, complete posteriorly. Acrostichal bristles 2-serial, complete posteriorly.

LEGS. With fore tibia and tarsus (tarsomere 5 darker), mid femur in apical part, hind femur (except narrow basal space), mid and hind tarsomeres 5 brownish, otherwise legs yellow. Hind trochanter lacking spinules. Fore femur markedly thickened, with rows of moderately long antero- and posteroventral bristles. Fore tibia spindle-like, with ordinary setation. Mid femur slender, with 2 strong, moderately long bristles near middle and 1 long, subapical bristle anteriorly. Mid tibia with black ventral spinules, lacking prominent bristles. Hind femur (viewed laterally) evenly thickened towards middle, with 1 row of short anteroventral bristles (4-5 subapicals longer) and some dorsal erect bristles near base. Hind tibia with unmodified posterior apical comb, clothed in ordinary setulae. Fore and mid tarsi slender, hind tarsomere 1 thickened.

WING. Normally developed, covered with uniform microtrichia; distinctly brownish infuscate. Costal vein with short setulae along anterior margin. R 2+3 long, meeting costa beyond middle of wing. Distance between apices of R 2+3 and R 4+5 about 1.5 times shorter than distance between apices of R 1 and R 2+3. R 4+5 strongly curved towards costa in apical part. M 1+2 evenly bowed. Halter with black knob and pale stem. ABDOMEN. With tergites (except tergite 8) weakly sclerotised, brownish yellow. Tergite 1 produced laterally into projection bearing 3 short bristles and resting in shallow sclerotised excavation on tergite 2. Sternites 2-4 divided. Gland-like structure not prominent.

TERMINALIA. Brown ( Figs 229-231View Figs 229-231). Cerci broadly fused, short, left cercus with 3 very long strong terminal bristles. Epandrium completely divided. Left epandrial lamella fused to hypandrium, with 1 long seta apically. Left surstylus ( Fig. 231View Figs 229-231) with upper lobe divided; lower part with markedly developed surstylar comb and additional short internal apophysis bearing 3 short setae, upper part short, slender, digitiform, with 1 subapical seta. Right epandrial lamella ( Fig.230View Figs 229-231) subtriangular, covered with numerous setae of different lengths. Right surstylus ( Fig. 229View Figs 229-231) not prominent. Hypandrium with 2 very long, strong setae apically. Phallus short.


Mid tibia lacking ventral spinules. Segment 8 elongate, with tergite and sternite separated; sternite 8 with apical part somewhat hinged. Cercus elongate oval, brownish. Otherwise as in male.

Material examined

Holotype ♂ SINGAPORE: Sime forest , 16 September 2005, forest, Mal 1 (reg. 25352, leg. P.G.; in ZRC). 


SINGAPORE: 3 ♂♂, 1 ♀, Sime forest, 24 March 2005, forest, sweeping (reg. 25026, leg. P.G.); 3 ♂♂, 1 ♀, Sime forest, 15 April 2005, forest, sweeping (reg. 25061, leg. P.G.); 1 ♂, 2 ♀♀, Sime forest, 1 July 2005, forest, sweeping (reg. 25191, leg. P.G.); 1 ♂, 2 ♀♀, Sime forest, 22 July 2005, forest, Mal 1 (reg. 25270, leg. P.G.); 1 ♂, Sime forest, 19 August 2005, forest, Mal 1 (reg. 25299, leg. P.G.); 1 ♂, Sime forest, 7 September 2005, forest, Mal 1 (reg. 25334, leg. P.G.); 1 ♂, 1 ♀, Sime forest, 18 November 2005, forest, Mal 1 (reg. 25420, leg. P.G.); 1 ♀, Sime forest, 3 December 2005, forest, Mal 1 (reg. 25434, leg. P.G.).


The new species is named after the country of origin, Singapore.



Habitat and seasonal occurrence

This species was collected in forests, with records from March-April, July-September and November- December.


In having modified male abdominal tergites 1 and 2, the new species is closely related to S. paradoxus Shamshev and Grootaert  described from Thailand ( Shamshev & Grootaert 2004b). However, S. paradoxus  can be readily distinguished from S. singaporensis  sp. nov. in the slightly arcuate R 4+5 (vs. vein R 4+5 strongly curved towards costa in the new species). Additionally, in the male of S. paradoxus  the hind femur is constricted and bent near the middle and the hind tibia bears a long spur-like posterior apical comb. The relationships of both species with Stilpon  are not clear.