Platypalpus singaporensis, 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 : 16-17

Platypalpus singaporensis sp. nov.

Figs 10 , 19 , 244

Diagnosis

Species of the P. luteus group with 2 pairs of verticals. Body almost uniformly yellowish, except for mesonotum with two pale brown vittae down dorsocentral bristles; antenna pale yellow, postpedicel ellipsoid, about twice as long as wide; stylus 2.0 times as long as postpedicel; acrostichals and dorsocentrals multiserial, hardly separated; 2 notopleurals; anepisternum (= mesopleuron) above with row of short brown setae; tarsomeres 3 and 4 of fore tarsus somewhat flattened, but not produced with posterior wing-like protuberance.

Description

Male

Unknown.

Female

LENGTH. Body 3.3 mm; wing 2.0 mm.

HEAD. Entirely yellow in ground-colour (ocellar tubercle with slight brownish tinge). Occiput with 2 pairs of black verticals, further clothed with rather short bristly hairs, longer setae on lower part. Ocellar tubercle with 2 long, black bristles. Frons pale yellow, widened toward ocellar tubercle, above antennae about 1.5 times as wide as anterior ocellus, pollinose. Face below antennae nearly as broad as frons. Antenna entirely pale yellow; postpedicel ellipsoid ( Fig. 19 ), about 2.0 times as long as wide; stylus nearly 2.0 times as long as postpedicel. Palpus brown, elongate, about as long as postpedicel, with 1 long brown apical, 1 subapical and 1 subbasal setae. Proboscis yellow, long, as long as head is high.

THORAX. Almost entirely yellow; scutum with 2 brownish vittae down dorsocentrals; pleura yellowishbrown; long bristles black, short hairs brown. Postpronotal lobe with 1 moderately long bristle and several setulae. Mesonotum with 2 long notopleurals, 1 postalar and 4 scutellars (outer pair very short, inner pair long); acrostichals and dorsocentrals short, multiserial, hardly separated, 1 pair of prescutellar dorsocentrals long; anepisternum (= mesopleuron) with row about 8 brown setae along upper border.

LEGS. Uniformly yellow. Fore femur thickened, with very short anteroventral and posteroventral bristles and long dorsal hairs near base. Length of fore femur, fore tibia and fore tarsus (mm): 0.6/0.6/0.52; fore tarsomeres (mm): 0.2/0.1/0.06/0.05/0.09. Fore tarsus slightly shorter than fore tibia; tarsomere 1 with some longer hair-like setae near base; tarsomeres 3-5 flattened, but not produced posteriorly; tarsomere 5 with long posterior seta at tip. Mid femur incrassate, 1.5 times wider than fore femur, with 2 rows of black ventral spinules (posterior ones longer) and row of 8-10 brown, posteroventral bristles about 3/4 as long as femur is wide. Mid tibia with short, flattened, yellow apical spur. Mid tarsus about 3/4 of length of mid tibia. Hind leg ordinary.

WING. Hyaline, with yellowish veins, bearing 2 long costal bristles. Veins R 4+5 and M 1+2 divergent near middle, convergent just before meeting wing margin. Crossveins m-cu and r-m contiguous. Calypter brown, with ciliae brown basally and pale apically. Halter with brown stem and white knob.

ABDOMEN. With tergite 1 very narrow, tergites 2-5 wide as usual and brown, tergites 6-8 pale; sternites pale, only sternite 8 and cercus brownish.

Material examined

Holotype ♀

SINGAPORE: Sime forest, 3 June 2005, forest, Mal 1 (reg. 25134, leg. P.G.; in ZRC).

Paratypes

SINGAPORE: 1 ♀, Sime forest, 6 May 2005, Mal 1 (reg. 25127, leg. P.G.); 1 ♀, Sime forest, 12 August 2005, Mal 1 (reg. 25293, leg. P.G.).

Etymology

The new species is dedicated to Singapore.

Distribution

Singapore.

Habitat and seasonal occurrence

Forest, recorded from May until August.

Remarks

Platypalpus singaporensis sp. nov. belongs to the P. luteus group as indicated by the long yellow proboscis and many other features ( Grootaert & Shamshev 2006). It is however aberrant because it lacks the broadened fore tarsi like other members of the group. Platypalpus singaporensis sp. nov. has to be compared mainly with P. hualuang Grootaert & Shamshev , a similar species from Northeast Thailand. There are however so many crucial differences that show the plasticity of the P. luteus group. Remarkable is the presence in P. singaporensis sp. nov. of a row of about 8 setae along the upper margin of the anepisternum. A feature that is unique in Platypalpus . However, in P. hualuang one or two short yellowish setae are present, a character that we overlooked in the original description of this species.

In P. hualuang , the following characters are different: antenna onion-shaped ( Fig. 20 ), palpus small, round, pale yellow; a pair of short pale yellow ocellar bristles; two pairs of short, pale verticals; 1 notopleural; a brown median band on mesonotum; fore tibia not swollen in basal half and without black dorsal bristles; tarsi paler than tibiae, almost white; fore tarsus very long, longer than tibia; fore tarsomere 1 with a long white bristle near base; fore tarsomere 3 and 4 flattened and widened, due to a wing-like posterior protuberance; mid femur with about 6 posteroventral bristles about half as long as femur is wide; mid tarsus long, as long as mid tibia.

Platypalpus singaporensis sp. nov. differs from P. hualuang as follows: antenna ellipsoid; palpus elongate, brown; a pair of long black ocellar bristles; two pairs of long black verticals; a narrow brown vitta on each row of dorsocentrals, median area of mesonotum yellow; 2 notopleurals; fore tibia swollen in basal half and dorsally with some long black bristles; fore tarsus distinctly shorter than fore tibia; all tarsi yellow, not paler than tibiae; fore tarsomere 1 without long basal pale ventral bristle, only with longer ventral pubescence; fore tarsomeres 3, 4 and 5 flattened, but not widened; mid femur with a row of 8-10 brown posteroventral bristles that are at least 3/4 as long as femur is wide; mid tarsus short, about 3/4 length of mid tibia.

Figures

Figs 10-18. Wings of Tachydromiinae. 10. Platypalpus singaporensis sp. nov. 11. Tachydromia luang Shamshev & Grootaert, 2005. 12. Chersodromia sylvicola sp. nov. 13. Chersodromia glandula sp. nov. 14. Drapetis laut sp. nov. 15. Elaphropeza biuncinata (Melander, 1928). 16. Crossopalpus temasek sp. nov. 17. Stilpon laawae Shamshev & Grootaert, 2004. 18. Nanodromia narmjeud Grootaert & Shamshev, 2003.

Figs 19-26. Antennae of Tachydromiinae. 19. Platypalpus singaporensis sp. nov. 20. Platypalpus hualuang Grootaert & Shamshev, 2006. 21. Tachydromia luang Shamshev & Grootaert, 2005. 22. Drapetis mandai sp. nov. 23. Drapetis hutan sp. nov. 24. Chersodromia singaporensis Shamshev & Grootaert, 2005. 25. Crossopalpus temasek sp. nov. 26. Stilpon singaporensis sp. nov.