Drapetis laut

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: 60-62

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Drapetis laut

sp. nov.

Drapetis laut  sp. nov.

Figs 98-100View Figs 98-100


Rather small species; antennal scape and pedicel brownish yellow, postpedicel brownish; palpus pale; legs brownish yellow; halter pale.


Male LENGTH. Wing 1.5-1.6 mm.

HEAD. Black. Occiput subshining, finely pollinose. Two long vertical bristles present. Frons subshining, broadened towards ocellar tubercle. Anterior ocellars long, yellow; posterior ocellars minute. Antenna with scape and pedicel brownish yellow, postpedicel brownish; pedicel with moderately long ventral seta; postpedicel with lower margin somewhat convex, rather long, about 2.0-2.2 times longer than wide; stylus nearly 3.0 longer than postpedicel and about 2.0 times longer than scape, pedicel and postpedicel combined. Palpus pale, with moderately long subapical seta.

THORAX. Black. Mesopleuron pubescent. Prothoracic episternum with 1 long upturned bristle just above fore coxa and some setulae on upper part. Postpronotal bristle not prominent. Mesonotum with 2 notopleurals, 1 postsutural-supra-alar, 1 postalar and 4 scutellars (inner pair very long, cruciate; outer pair very short). Scutum wholly covered with short, pale uniform (except for 1 pair of long prescutellars) setulae.

LEGS. Brownish yellow, with hind femur, all tibiae and tarsi darker in different extents (in darker specimens hind femur and all tibiae brownish). Coxae and trochanters with unmodified setation. Fore femur somewhat thickened. Femora and tibiae mostly with inconspicuous setation; mid femur with 1 anterior subapical bristle; hind femur thickened in apical 2/3, with several longer anteroventral subapical bristles. Hind tibia with slightly prominent apical projection. Hind tarsomere 1 lacking prominent ventral spinules near base.

WING. Normally developed, hyaline, covered with uniform microtrichia; veins yellowish to brownish yellow. Costal vein with short setulae along anterior margin. Costal bristle short, brownish. Costal index: 52/15/41. Rs originating before middle of cell r 1 (closer to humeral crossvein), nearly as long as crossvein bm-cu. R 1 thickened, meeting costa about middle of wing. R 2+3 evenly bowed toward costa, meeting costa beyond middle of wing. R 4+5 and M 1+2 convergent in apical part. R 4+5 slightly sinuate. A 1 absent. Crossvein bm-cu somewhat oblique. Crossvein r-m somewhat beyond middle of cell bm. Halter pale.

ABDOMEN. With tergite 1 pale yellow, tergites 2-7 brownish, rectangular, of subequal width, with scattered setulae, tergites 3 and 4 with squamiform setae laterally; segment 8 brown; tergites 6 and 7 divided along midline. Sternite 2 divided, sternites 3 and 4 with excision posteriorly. Gland-like structures present between tergites 3-4 and 4-5.

TERMINALIA. Brown ( Figs 98-100View Figs 98-100). Cerci separated; left cercus broad, as in Fig. 99View Figs 98-100, with numerous unmodified short setae; right cercus greatly reduced, represented as narrow, bacilliform sclerite bearing several short setulae. Epandrium completely divided. Left epandrial lamella fused to hypandrium, with 4 long setae apically. Left surstylus ( Fig. 100View Figs 98-100) bilobed; upper lobe long, digitiform, with numerous long unmodified setae; lower lobe short, rather subtriangular, with several short unmodified setae. Right epandrial lamella ( Fig. 98View Figs 98-100) subtriangular, covered with numerous unmodified long setae. Right surstylus bilobed; upper lobe subtriangular, with broadly rounded apex, bearing several long unmodified setae; lower lobe similar in shape to upper lobe but narrower, with short unmodified setae. Hypandrium lacking setation. Phallus elongate. Two rod-shaped apodemes present.


Abdomen with tergites 6 and 7 undivided; segment 8 with separated tergite and sternite; sternite 8 undivided. Cercus elongate oval, brownish. Otherwise as in male.

Material examined

Holotype ♂ SINGAPORE: Chek Jawa , 12 September 2005, mangrove, sweeping (reg. 25343, leg. P.G.; in ZRC). 


SINGAPORE: 6 ♂♂, 10 ♀♀, Chek Jawa, 19 November 2003, mangrove, sweeping (reg. 23080, leg. P.G.); 2 ♂♂, 5 ♀♀, Chek Jawa, 12 September 2005, mangrove, sweeping (reg. 25343, leg. P.G.); 11 ♂♂, 2 ♀♀, Chek Jawa, 15 December 2005, mangrove, sweeping (reg. 25452, leg. P.Grootaert); 4 ♀♀, Chek Jawa, 15 December 2005, mangrove, sweeping (reg. 25452, leg. P.G.).

MALAYSIA: 1 ♀, Pulau Tioman, Juara, 20 July 2005, river, sweeping (reg. 25246, leg. P.G.).

Sequences in Genbank

♂, Chek Jawa, 15 December 2005, mangrove, sweeping (reg. 25452, leg. P.Grootaert) quoted in Lim et al. (2009) as Drapetis  sp. Si1328 has been sequenced.


The specific name 'laut' means 'sea' in Malay.

Distribution and seasonal occurrence

Malaysia, Singapore.

Habitat and seasonal occurrence

This species occurs in mangroves, with records from July (single case), September, November and December.


The new species is similar to D. pantai  sp. nov. and the main distinguishing features are indicated in the key.