Platypalpus siamensis, 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 : 4048-4050

Platypalpus siamensis sp. nov. (male)

( Figures 19–21 )

Etymology

The name ‘‘siamensis’’ refers to the ancient name of Thailand.

Diagnosis

Mostly yellow species; one pair of verticals; antenna wholly yellowish brown, postpedicel 4.0 times longer than wide, arista 2.0 times longer than postpedicel; mesonotum with two brownish spots, mesopleuron partly brownish; fore tibia and tarsus somewhat darkened, otherwise legs yellow.

Material examined

Holotype: male, Thailand, Loei province, Na Haeo , FIRS, 15–22 October 2003, Malaise trap (2), leg. P. Grootaert and Siriluck Intarasri.

Male

Body length 2.5 mm; wing length 2.6 mm.

Head. Black in ground-colour. Occiput finely greyish pollinose, subshining, bearing two moderately long verticals. Ocellar tubercle with two moderately long bristles and two minute setulae. Frons pollinose, 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 2.0 times longer than postpedicel. Palpus wholly yellow, mostly with scattered, short, yellow bristly hairs, bearing one rather long, brownish yellow, subapical bristle.

Thorax. Largely yellow; prothoracic notum with brownish spot; suture between proepisternum and mesopleuron brown; mesonotum with two brownish, indistinct, elongate oval spots above wings; sternopleuron and hypopleuron largely (except for apical part) brownish. Mesonotum and sternopleuron shining, otherwise thorax finely pollinose, subshining. Anterior and posterior spiracles brown. Humerus with one very short bristle. Mesonotum with two brownish notopleural (anterior one shorter and thinner), one postalar (similar to posterior notopleural), and four scutellar (outer ones very short, thin; inner ones longest among mesonotal bristles, cruciate) bristles; some scattered setulae present behind humerus, on notopleural depression, supra-alar space and postalar callus. Acrostichals lacking. Dorsocentrals arranged in one regular row, short, mostly of equal length (except for two pairs of longer prescutellars).

Legs. Almost wholly yellow; fore tibia and tarsus somewhat darkened. 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. 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, brown, posteroventral bristles. Mid tibia with black ventral spinules throughout and hardly prominent flattened apical spur. Hind leg long, slender; hind femur bearing a row of short, brownish to brownish yellow, erect, antero- and a row of short, pale, posteroventral bristles.

Wing. Slightly infuscate, with yellowish brown veins, bearing one very long, brownish, basicostal bristle. 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 and with long yellow fringes. Halter pale yellow.

Abdomen. Yellowish brown, with ordinary, mostly inconspicuous, setation.

Terminalia. Yellowish brown, small. Left epandrial lamella ( Figure 20 ) with short, rather digitiform, apical part, clothed with numerous moderately long bristles. Left surstylus subtriangular, with several moderately long bristles. Right epandrial lamella ( Figure 21 ) subrectangular, clothed with numerous, long bristles. Right surstylus subtriangular, with several short bristles. Cerci ( Figure 19 ) digitiform, moderately long (left cercus distinctly longer), clothed with numerous long bristles, pubescent. Hypoproct ( Figure 20 ) enlarged but not extending beyond apices of cerci, with two spine-like extensions ventrally.

Female

Unknown.

Distribution

Thailand.

Remarks

Main distinguishing features of P. siamensis sp. nov. are given in the key and have been discussed under the ‘‘Remarks’’ to P. thaicus sp. nov.

Figures

Figures 19–21. Platypalpus siamensis sp. nov., male. (19) Epandrium with cerci and hypoproct. (20) Left epandrial lamella, left cercus and hypoproct (lateral view). (21) Right epandrial lamella (dorsal view). Scale bar: 0.1 mm.