Platypalpus gaemluang, 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 : 4042-4044

Platypalpus gaemluang sp. nov. (male)

( Figures 11–14 )

Etymology

The name ‘‘gaemluang’’ refers to the yellow spot on the cheeks (in Thai ‘‘gaem’’ means ‘‘cheek’’ and ‘‘luang’’ means ‘‘yellow’’).

Diagnosis

Mostly yellow (including legs) species; one pair of verticals; occiput narrowly densely greyish pollinose behind eyes and in upper part, otherwise subshining, with yellowish spot near mouth-opening laterally; antenna wholly yellowish brown, postpedicel 4.5 times longer than wide, arista 3.0 times longer than postpedicel; mesonotum and mesopleuron wholly yellow.

Material examined

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

Male

Body length 3.1 mm; wing length 3.0 mm.

Head

Largely black in ground-colour, with small yellowish spot near mouth-opening laterally, including jowls. Occiput narrowly densely greyish pollinose behind eyes and also in upper half, including vertex and ocellar tubercle, otherwise subshining; clothed with pale bristly hairs of different length, bearing two proclinate, moderately long verticals. Ocellar tubercle lacking bristles (missing?). 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 4.5 times longer than wide. Arista nearly 3.0 times longer than postpedicel. Palpus wholly yellow, small, mostly with scattered short yellow bristly hairs, bearing one longer, brownish yellow, subapical bristle.

Thorax. Almost wholly yellow; prothoracic notum yellowish brown dorsally; suture between proepisternum and mesopleuron brown. Mesonotum and sternopleuron shining, otherwise thorax finely pollinose, subshining. Anterior and posterior spiracles yellow. Humerus with one minute bristle. Mesonotum with two brownish notopleural (anterior one shorter and thinner), one postalar (similar to posterior notopleural) and two cruciate scutellar bristles; some scattered setulae present behind humerus, on notopleural depression, supra-alar space and postalar callus. Acrostichals lacking. Dorsocentrals inconspicuous, pale yellow, arranged in one regular row, mostly of equal length (except for one pair 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, 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 2.0 times broader than fore femur; with rows of ventral, black spinules and a row of long (nearly as long as femur is deep), brown, posteroventral bristles. Mid tibia with black ventral spinules throughout and short, 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. Hyaline, with yellowish veins, bearing one moderately long, brownish, basicostal bristle. Vein M1+2 somewhat bowed in apical part but parallel to vein R4+5 near wingapex. 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. Yellow to brownish yellow, shining, with pale yellow setation. Tergites 1–2 with somewhat longer and numerous setae. Sternites with rather numerous moderately long bristles becoming longer toward terminalia.

Terminalia. Largely yellow, moderately large, elongate, rotated 45 °, hypandrium brownish yellow. Left epandrial lamella ( Figure 12 ) pointed at apex and with numerous long bristles in apical part. Left surstylus rather large, subtriangular, with several long bristles. Right epandrial lamella ( Figures 13, 14 ) subtriangular, with short pointed process, clothed with numerous long bristles. Right surstylus short, subtriangular. Cerci ( Figure 11 ) digitiform, long (left cercus longer), pubescent, clothed with moderately long bristles. Hypoproct ( Figures 11, 14 ) greatly modified, extending far beyond apices of cerci, overlapping apical part of right epandrial lamella, broad ovate in apical part.

Female

Unknown.

Distribution

Thailand.

Remarks

P. gaemluang sp. nov. is most closely related to P. phomyaaw sp. nov., as has been also reflected in the key to species. In both species the mesonotum is entirely yellow and the male terminalia have a very similar structure, especially that of the hypoproct. P. phomyaaw sp. nov. can be readily distinguished from P. gaemluang sp. nov. by a peculiar setation of the abdominal sternites 5 and 6 where two and four very long, closely set bristles are present, respectively. Additionally, P. phomyaaw sp. nov. has partly brown thoracic pleura.

Figures

Figures 11–14. Platypalpus gaemluang sp. nov., male. (11) Epandrium with cerci and hypoproct. (12) Left epandrial lamella (lateral view). (13) Right epandrial lamella (lateral view). (14) Right epandrial lamella and apical part of hypoproct (dorsal view). Scale bar: 0.1 mm.