Drapetis bakau, 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 : 54-57

Drapetis bakau sp. nov.

Figs 87-91 , 93

Diagnosis

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

Description

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. 88 ) 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. 93 ) with 2 longer anteroventral subapical bristles. Hind tibia with slightly prominent apical projection. Tarsi of all legs unmodified, with ordinary setation.

WING. ( Fig. 87 ) 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 89-91 ). 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. 96 ) bilobed; upper lobe digitiform, with numerous unmodified setae apically; lower lobe somewhat shorter, with several unmodified setae. Right epandrial lamella ( Fig. 95 ) subtriangular, covered with numerous unmodified setae of different lengths. Right surstylus bilobed ( Fig. 94 ); 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.

Female

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).

Paratypes

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.).

Etymology.

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

Distribution

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.

Remarks

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

Figures

Figs 87-91. Drapetis bakau sp. nov., ♂. 87. wing, dorsal view. 88. head, lateral view. 89. right surstylus, dorsal view. 90. epandrium and cerci, dorsal view. 91. left surstylus, lateral view.

Figs 92-93. Hind leg of Drapetis, ♂, anterior view. 92. D. pantai sp. nov. 93. D. bakau sp. nov.

Figs 94-97. Drapetis hutan sp. nov., ♂. 94. antenna, lateral view. 95. right surstylus, dorsal view. 96. epandrium and cerci. 97. left surstylus, lateral view.