Tachydromia ocellata, Shamshev, Igor & Grootaert, Patrick, 2008

Shamshev, Igor & Grootaert, Patrick, 2008, New and little-known species of the genus Tachydromia Meigen (Diptera, Hybotidae) from Thailand, Zootaxa 1830, pp. 21-36 : 29-31

Tachydromia ocellata sp. nov.

( Figs 10–12 , 27, 31 )

Diagnosis. Palpus yellow. Legs with complicated colour pattern. Male wing with vein R2+3 incomplete; 2 rounded dark brown spots present on subapical part. Halter yellow.

Description. Male. Wing 1.6–1.7 mm. Head black in ground-colour. Eyes extending beyond ocellar tubercle. Frons pollinose, slightly widened toward ocellar tubercle, above antennae nearly 1.5 times as broad as anterior ocellus. Ocellars minute. Occiput finely pollinose; with 2 moderately long strong black setae in upper part, 2 similar setae on middle part laterally and numerous pale hair-like setae near neck and on lower part. Basal antennal segments brownish yellow; postpedicel yellow, small, elongate oval; stylus very long, brownish, short pubescent. Proboscis almost entirely yellow, brownish at tip. Palpus unmodified, small, rounded, yellow, with 1 very long black and 1 pale short thin subapical setae.

Thorax brown in ground-colour, largely shining; prominent setae black; prothoracic sclerites (except postpronotal lobe) finely pollinose. Postpronotal lobe very large, lacking conspicuous setae. Mesonotum with 2 notopleural (posterior longer and stronger) and 2 scutellar (shorter than posterior notopleural) setae; acrostichals and dorsocentrals minute; the former arranged in 1–2 irregular rows, lacking on prescutellar depression; the latter uniserial, 1 prescutellar pair as long as scutellar setae.

Legs long, with complicated colour pattern; fore tibia brownish anteriorly and posteriorly; fore tarsomeres 4 and 5 brown; mid femur brownish posteriorly on apical 2/3; mid tibia entirely brownish; mid tarsomeres largely brownish, basitarsus paler basally; hind femur brown on about apical 1/2; hind tibia brown on apical 1/ 4; hind tarsomere 2 brownish on about apical 1/2, tarsomeres 3–5 entirely brownish; otherwise legs yellow. Coxae with yellowish to brownish yellow setae of different length; no setae between fore and mid coxae. Fore femur strongly thickened, with minute brownish yellow, anteroventral and posteroventral spinule-like setulae, bearing 2 longer black spinulae near base. Fore tibia spindle-like, with unmodified setation. Mid femur slen- der, with rows of anteroventral and posteroventral spinule-like setae (the latter black and somewhat longer) and 2 long pale hair-like setae near base. Mid tibia slender, bearing ventral spinule-like setulae. Hind femur slender, with rows of very short anterodorsal and posteroventral setae. Hind tibia slender, lacking prominent bristles, with rounded posterior apical comb.

Wing ( Fig. 27 ) tip deformed, with modified venation, costal vein curved in subapical part, vein R2+3 incomplete, disappearing before meeting of vein R1 with costa; entirely finely brownish infuscate and with 2 rounded dark brown spots on virtual meeting point of vein R2+ 3 in costa and near wing apex between veins R4+5 and M1+2. Basal costal seta absent. Vein R1 meeting costa near wing midway. Proximal section of vein R4+5 considerably longer than Rs. Veins R4+5 and M1+2 strongly divergent toward wing-apex. Crossveins r-m and bm-cu confluent. Cells br and bm extending to wing midway. Halter yellow.

Abdomen brownish (segments 1–2 paler), subshining, covered mostly with scattered, short, black setulae; segments 7 and 8 with moderately long setae. Terminalia ( Figs 10–12 ) rather large, brown, elongate oval. Right cercus bilobed, with both lobes digitiform, curved, bearing some unmodified setae of different lengths; right lobe somewhat longer and narrower. Left cercus quite long, broadened apically and basally, narrow on middle part, with numerous unmodified setae of different lengths. Right epandrial lamella subtriangular (viewed laterally), with large rounded ventral process in subapical part, bearing numerous setae of different lengths. Right surstylus long, narrow, bent inward, with several spine-like sensilla on inner side. Left epandrial lamella subtriangular, bearing several unmodified setae of different lengths. Left surstylus short, subrectangular, with several unmodified setae.

Female.

Body length: 1.75–2 mm; wing: 1.5–1.75 mm.

Wing ( Fig. 31 ) not deformed like in male and vein R2+3 complete, ending in costa; only one rounded dark brown spot present beyond end R2+3. The spot can be variable in colour intensity. The tip of the wing is white. Structure and colour pattern of legs identical to male.

Material examined. Holotype male: THAILAND Loei prov., Phu Ruea NP Subhnonghin 17°28.772'N 101°21.308'E 860 m Malaise trap 26.vii–2.viii.2006 Nukoonchai Jaroenchai leg. T319.

Paratypes: THAILAND Phetchabun prov., Nam Nao NP Helicopter landing ground 16°43.156'N 01°35.118'E 890 m Malaise trap 1 male, 1 female, 17.vii.2006 – 24.vii.2006 (T276); 1 male, 24–30.vii.2006 (T278); 4 females, 24.vii.2006 – 30.vii.2006 (T279) Noopean Hongyothi leg.

1 female Chaiyaphum prov., Pa Hin Ngam NP, Ecotone between mix deciduous/dry dipterocarp, 15°38.100'N 101°23.857'E, 700m, 18.viii.2006 – 24.viii.2006, Malaise trap, (T446) Katae Sanog & Buakaw Adnafai leg.

2 males, 7 females, Loei prov., Phu Ruea NP, Pan Hin Khan Maak ditch, 17°30.042'N 101°20.474'E, 1219m, 12.viii.2006 – 19.viii.2006, Malaise trap, (T528); 2 females, 26.viii.2006 – 2.ix.2006 (T534), Nukoonchai Jaroenchai leg.; 3 males, 1 female, Loei prov., Phu Ruea NP, Huay Taey ditch, 1233m, 12.viii.2006 - 19.viii.2006, Malaise trap, (T529); 3 males, 3 females, 26.viii.2006 – 2.ix.2006 (T535) Nukoonchai Jaroenchai leg.; 3 males, 5 females, Loei prov., Phu Ruea NP, Nern Wibaak ditch, 19.viii.2006 – 26.viii.2006, 1196m (T530) Nukoonchai Jaroenchai leg.; 1 female, Loei prov., Phu Ruea NP, Pah Lo Noy, 17°30.502'N 101°20.868'E, 1343m, 12.ix.2006 – 19.ix.2006, Malaise trap, (T827) Nukoonchai Jaroenchai leg.

1 female, Sakon Nakhon prov., Phu Phan NP, Kam Hom waterfall at Haew Sin chai, 17°07.415'N 104°01.179'E, 347m, 4.ix.2006 – 10.ix.2006, Malaise trap, (T610) Sailom Tongboonchai leg.

Derivatio nominis. The name alludes to the two brownish spots on the tip of the wing.

Distribution. Thailand.

Remarks. Tachydromia ocellata sp. nov. is closely related to T. luang sharing similar setation of the right surstylus (several spine-like sensilla on inner side). The new species can be readily distinguished from other Tachydromia known from the Oriental Region by its unique venation and pattern of the wing.

Figures

FIGURES 10 – 12. Tachydromia ocellata sp. nov. 10. right epandrial lamella, ventral view. 11. epandrium with cerci. 12. left epandrial lamella with surstylus, lateral view. Scale 0.1 mm.

FIGURES 24 – 31. Wings. 24. Tachydromia phanensis sp. nov. 25. Tachydromia phu sp. nov. 26. Tachydromia tigeri sp. nov. 27. Tachydromia ocellata sp. nov. male. 28. Tachydromia luang Shamshev, Grootaert. 29. Tachydromia monocercus sp. nov. 30. Tachydromia doi sp. nov. 31. Tachydromia ocellata sp. nov. female.