Drapetis bakau

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: 54-57

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Drapetis bakau

sp. nov.

Drapetis bakau  sp. nov.

Figs 87-91View Figs 87-91, 93View Figs 92-93


Rather small species; antenna yellow; palpus pale yellow; legs yellow. Halter pale.


Male LENGTH. Wing 1.5-1.6 mm.

HEAD. Black. Occiput subshining, finely pollinose. Two short, yellow vertical bristles present. Frons subshining, broadened towards ocellar tubercle. Anterior ocellars short, yellow; posterior ocellars minute. Antenna ( Fig. 88View Figs 87-91) yellow (in darker specimens with brownish tinge); pedicel with moderately long ventral seta; postpedicel with lower margin somewhat convex, rather long, 2.5-2.8 times longer than wide; stylus nearly 2.0 longer than postpedicel and about 1.3 times longer than scape, pedicel and postpedicel combined. Palpus pale yellow.

THORAX. Brown. 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 entirely covered with short, pale uniform (except for 1 pair of long prescutellars) setulae.

LEGS. Including coxae uniformly yellow. 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 ( Fig. 93View Figs 92-93) with 2 longer anteroventral subapical bristles. Hind tibia with slightly prominent apical projection. Tarsi of all legs unmodified, with ordinary setation.

WING. ( Fig. 87View Figs 87-91) 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: 40/9/43. Vein Rs originating before middle of cell r1 (closer to humeral crossvein), nearly as long as crossvein bm-cu. R 1 thickened. R 2+3 evenly bowed toward costa. R 4+5 and M 1+2 convergent in apical part. A 1 absent. Crossvein bm-cu somewhat oblique. Crossvein r-m 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. Sternites not divided. Glandlike structure present between tergites 3-4 and 4-5.

TERMINALIA. Rather large, brown ( Figs 89-91View Figs 87-91). Cerci separated; left cercus broad, subrectangular, bent in middle, with numerous unmodified setae of different lengths; right cercus greatly reduced, represented as narrow, bacilliform sclerite bearing several short setulae. Epandrium completely divided. Left epandrial lamella fused to hypandrium, lacking setae apically. Left surstylus ( Fig. 96View Figs 94-97) bilobed; upper lobe digitiform, with numerous unmodified setae apically; lower lobe somewhat shorter, with several unmodified setae. Right epandrial lamella ( Fig. 95View Figs 94-97) subtriangular, covered with numerous unmodified setae of different lengths. Right surstylus bilobed ( Fig. 94View Figs 94-97); upper lobe digitiform, with several short setae; lower lobe subtriangular, with several unmodified setae. Hypandrium reduced, lacking setation. Phallus short. Two rod-shaped apodemes present.


Abdominal segment 8 with sclerites separated; sternite 8 brown, with completely separated apical part. Cercus elongate oval, brownish. Otherwise as in male.

Material examined

Holotype ♂

SINGAPORE: Chek Jawa, 19 November 2003, mangrove, sweeping (reg. 23080, leg. P.G.; in ZRC).


SINGAPORE: 15 ♂♂, 15 ♀♀, Chek Jawa, 19 November 2003, mangrove, sweeping (reg. 23080, leg. P.G.); 8 ♂♂, 5 ♀♀, Chek Jawa, 12 September 2005, mangrove, sweeping (reg. 25343, leg. P.G.); 1 ♂, Chek Jawa, 15 December 2005, mangrove, sweeping (reg. 25452, leg. P.G.); 3 ♂♂, 12 ♀♀, Chek Jawa, 15 December 2005, mangrove, sweeping (reg. 25452, leg. P.G.); 2 ♂♂, Nee Soon, 19 August 2005, swamp forest, Mal 2 (reg. 25297, leg. P.G.); 1 ♂, Sime forest, 1 July 2005, forest, sweeping (reg. 25191, leg. P.G.).

MALAYSIA: 18 ♂♂, 6 ♀♀, Pulau Tioman, Juara, 20 July 2005, river, sweeping (reg. 25246, leg. P.G.); 5 ♂♂, 1 ♀, Pulau Tioman, Monkey Bay, 14 July 2005, beach, sweeping (reg. 25216, leg. P.G.); 1 ♂, Pulau Tioman, Paya, 19 July 2005, secondary forest, sweeping (reg. 25239, leg. P.G.); 9 ♂♂, 2 ♀♀, Pulau Tioman, Paya, 19 July 2005, secondary forest, sweeping (reg. 25238, leg. P.G.).


The specific name 'bakau' means 'mangrove' in Malay.


Malaysia, Singapore.

Habitat and seasonal occurrence

This species occurs in mangroves, and rarely in terrestrial forest, with records from July, August, September, November and December.


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