Platypalpus thaicus, Grootaert & Shamshev, 2006

Grootaert, Patrick & Shamshev, Igor, 2006, The genus Platypalpus Macquart (Diptera: Hybotidae) from Northeast Thailand with comments on the species groups in the Oriental region, Journal of Natural History 39 (47), pp. 4031-4065 : 4045-4047

Platypalpus thaicus sp. nov. (male)

( Figures 15–18 )

Etymology

The name simply refers to the country of origin.

Diagnosis

Mostly yellow (including legs) species; one pair of verticals; antenna wholly yellowish brown, postpedicel 4.0 times longer than wide, arista 2.5 times longer than postpedicel; mesonotum with two brownish spots, mesopleuron partly brownish; anterior spiracle yellow, posterior one brown.

Material examined

Holotype: male, Thailand, Loei province, Na Haeo, Chang Tok waterfall, 17 May 2003, sweeping netting on vegetation bordering the river Mae Heuang (sample no. 23035), leg. P. Grootaert. Paratype: one male, Thailand, Loei province, Na Haeo, Khring Tok waterfall, 19 May 2003, sweep netting on vegetation bordering the river Mae Heuang (sample no. 23043), leg. P. Grootaert.

Male

Body length 2.3 mm; wing length 2.2 mm.

Head. Black in ground-colour. Occiput finely greyish pollinose, subshining; clothed with scattered pale and brownish yellow bristly hairs, bearing two proclinate, moderately long verticals. Ocellar tubercle with two moderately long bristles. Frons subshining, mostly very narrow, narrower than anterior ocellus, somewhat widened above. Face partly concolorous with frons, clypeus shining. Antenna yellowish brown, arista white, thick pubescent. Postpedicel narrow, elongate conical, nearly 4.0 times longer than wide. Arista nearly 2.5 times longer than postpedicel. Palpus wholly yellow, small, mostly with scattered, short, yellow bristly hairs, bearing one longer, brownish yellow, subapical seta.

Thorax. Largely yellow; prothoracic notum with brownish spot; prosternum brownish yellow; suture between proepisternum and mesopleuron brown; mesonotum with two small, elongate oval, indistinct, brownish yellow spots above wings; sternopleuron and hypopleuron largely brown to yellowish brown (except for upper part), metapleuron brownish yellow; postnotum with metanotum yellowish brown, metapleuron brown. Mesonotum and sternopleuron shining, otherwise thorax finely pollinose, subshining. Anterior spiracle yellow, posterior one brown. Humerus with one minute bristle. Mesonotum with two brownish notopleural (anterior one shorter and thinner), one postalar (similar to posterior notopleural) and two long scutellar (missing in holotype) bristles; some scattered setulae present behind humerus, on notopleural depression, supraalar space and postalar callus. Acrostichals lacking. Dorsocentrals arranged in one regular row, few in number, short, mostly of equal length (except for two pairs of longer prescutellars).

Legs. Wholly yellow. Coxae and trochanters with ordinary yellow to brownish yellow setae. Fore femur slender, with a row of brownish yellow, thin, posteroventral bristles (one longest one in middle part of femur longer than femur is deep) and a row of yellowish, short, thin, anteroventral bristles (nearly as long as femur is deep). Fore tibia mostly slender, somewhat swollen near tibial gland; clothed with ordinary setulae. Fore tarsus slender, unmodified. Mid femur incrassate, nearly 1.5 times broader than fore femur; with rows of ventral black spinules and a row of long (distinctly longer than femur is deep), brown, posteroventral bristles. Mid tibia with black ventral spinules throughout and hardly prominent, flattened, apical spur. Hind leg long, slender; hind femur somewhat swollen in apical part anteriorly, bearing a row of short, brownish to brownish yellow, erect, antero- and a row of short, pale, posteroventral bristles.

Wing. Slightly infuscate; basicostal bristle missing. Vein M1+2 somewhat bowed in apical part but parallel to vein R4+5 near wing-apex. Crossveins m-cu and r-m contiguous. Cell br broader than cell bm. Vein CuA2 somewhat sinuate, recurrent. Vein A1 long. Squama brownish yellow, with long, brownish fringes. Halter pale yellow.

Abdomen. With brownish yellow tergites and yellow sternites (except posterior margin of sternite 2), clothed with ordinary scattered setulae becoming on sternites longer toward terminalia.

Terminalia. Moderately large, rotated 45 °, yellow to brownish yellow. Left epandrial lamella ( Figure 16 ) subrectangular, with several long bristles in upper part. Left surstylus rather large, subrectangular, with several long bristles. Right epandrial lamella ( Figures 17, 18 ) subrectangular, clothed with scattered, long bristles, with digitiform process. Right surstylus short, subtriangular. Cerci ( Figure 15 ) digitiform, moderately long, of subequal length, pubescent, clothed with scattered, short bristles. Hypoproct ( Figures 15, 18 ) greatly modified, extending far beyond apices of cerci, overlapping apical part of right epandrial lamella, broadened in apical part, rounded at apex.

Female

Unknown.

Distribution

Thailand.

Remarks

In the key to the species given below P. thaicus sp. nov. has been included in a couplet jointed with P. siamensis sp. nov. described below. These two species are extremely similar in their external appearance and the best characters to distinguish them can be found in the male terminalia only. The terminalia of P. thaicus sp. nov. and P. siamensis sp. nov. are strikingly different, especially the structure of the hypoproct. Also, P. thaicus sp. nov. is likely to resemble P. nepalensis ( Brunetti, 1913) . However, some characters noted under the remark to P. nuadkhao sp. nov. indicate that they are two different species.

Figures

Figures 15–18. Platypalpus thaicus sp. nov., male. (15) Epandrium with cerci and hypoproct. (16) Left epandrial lamella (lateral view). (17) Right epandrial lamella (lateral view). (18) Right epandrial lamella and apical part of hypoproct (dorsal view). Scale bar: 0.1 mm.