Tachydromia australiensis, Grootaert, 2011

Grootaert, Patrick, 2011, The Genus Tachydromia Meigen (Diptera: Hybotidae) from Australia, Records of the Australian Museum 63 (1), pp. 103-112 : 104-105

Tachydromia australiensis n.sp.

Fig. 1

Type material. HOLOTYPE ♂, Australia, New South Wales, Wentworth Falls , Jamison Ck., cascades, 3.01.1994, B.J. Sinclair ( AMS 264358 ) . PARATYPES: 3♀♀, Wentworth Falls , Blue Mts, 6 Dec 1986, D.K. McAlpine, K.C. Khoo, R . de Keyzer ; AMS K258731 , AMS K258890 and AMS K258749 ; 1♀, 10 km SE Nowendoc , 850 m, on tree trunk, 25.03.1985, D.J. Bickel, AMS K258828 .

Diagnosis. Recognized by almost entirely brownish legs; fore femur yellowish on extreme apex.

Description. Male length: body 1.9 mm, wing 1.8 mm. Head black in ground-colour. Eyes with posterior margin produced far beyond ocellar tubercle; vertex narrower than frons in front of ocellar tubercle. Occiput including vertex almost entirely densely greyish pollinose, with shining patch behind mouth-opening; 2 inclinate, rather short, black postvertical setae, some pale setae around neck and near mouth-opening and row of minute postoculars. Ocellar tubercle pollinose, with 2 short lateroclinate setae. Frons greyish pollinose, slightly widened toward ocellar tubercle, above antennae nearly as broad as anterior ocellus. Antenna with scape and pedicel brownish yellow, postpedicel and stylus missing in holotype. Palpus unmodified, slender, rounded apically, shorter than proboscis, brownish; lacking silvery setae, with some scattered black setulae and bearing very long (nearly 1.5 times as long as palpus) black subapical seta. Thorax black in ground-colour, entirely greyish pollinose. Postpronotal lobe large, lacking conspicuous setae, with some minute setulae. Mesonotum with 1 notopleural (accompanied with 1 short setula anteriorly), 1 minute hair-like postalar and 2 scutellars (nearly as long as notopleural seta); some minute setulae present behind postpronotal lobe; mesosternum and metasternum bare between posterior four coxae. Acrostichals minute, arranged in 2 regular rows, ending before prescutellar depression. Dorsocentrals uniserial, mostly minute, prescutellar pair somewhat longer. Legs long, slender, almost entirely brownish; fore femur on extreme apex and knees yellowish; fore tibia and basal 2/3 of hind tibia brownish yellow, all tibiae paler dorsally; fore tarsomeres 1–3 yellowish, tarsomeres 4–5 brownish, mid and hind tarsomere 1 largely yellowish (except narrowly on apical part). Coxae mostly with short pale hair-like setae, bearing some longer and stronger setae apically (in some paratypes black subapical setae present), finely pollinose. Fore femur strongly thickened, pale pubescent ventrally, with pale and dark anteroventral and posteroventral setulae becoming longer basally. Fore tibia slightly spindle-shaped. Mid femur slender, slightly swollen on basal half, with rows of anteroventral and posteroventral spinule-like setulae on swollen part. Mid tibia slightly thickened toward apex, lacking subapical projection, with ventral spinule-like setulae. Hind leg unmodified, lacking prominent setae. Wing normally developed, rounded at apex, with unmodified venation; two broad brown bands connected on cells r 1 and r 2+3 leaving narrow basal (except extreme base), apical and median hyaline spaces. One short costal bristle present. Vein R 2+3 straight. Veins R 4+5 and M 1+2 parallel toward wing-apex. Crossveins r-m and bm-cu separated. Calypter pale coloured and fringed. Halter with whitish knob and brownish yellow stem. Abdomen largely black in ground- colour but with segments 1–2 almost entirely pale yellow leaving narrow brownish traces of sclerotization on tergites; greyish pollinose; covered with scattered black setae longer on pregenital segment. Terminalia ( Fig. 1 ) rather small, subglobular, blackish brown. Right cercus subtriangular, with unmodified short setae. Left cercus larger than right cercus, subrectangular viewed dorsally with left upper corner slightly produced and pointed (viewed laterally); with several unmodified setae of different lengths. Right epandrial lamella subtriangular (viewed laterally), lacking ventral subapical process, with several unmodified setae of different lengths. Right surstylus differentiated from epandrium, bent inward, subrectangular but with deep notch on right upper corner, bearing several spinule-like setae apically and on inner side. Left surstylus undifferentiated from epandrium; left epandrial lamella subtriangular, with several very long subapical ventral marginal setae. Hypandrium with 3 very short setae. Phallus short.

Female. Antenna with postpedicel and stylus brownish yellow to brownish; postpedicel, drop-like, short, about 1.5 times as long as wide; stylus very long, about 4.0 times as long as pedicel and postpedicel combined. Mid femur unmodified, slender, with rows of minute anteroventral and posteroventral setulae becoming longer basally. Mid tibia slender. Otherwise as in male. Cercus brown, long, slender, covered with minute setulae.

Etymology. The new species is named after the continent of its origin, Australia.

Distribution. This species is currently known from three localities in New South Wales. According to labels it was collected in the beginning of December and January and at the end of March (last sample on tree trunk, 850 m).

Figures

Fig.1. Tachydromia australiensis: (a) right surstylus, dorsal; (b) terminalia, dorsal; (c) apical part of left cercus, left lateral; (d) left epandrial lamella, lateral. Scale 0.1 mm.LC: left cercus; LE: left epandrial lamella; RE: right epandrial lamella; RE: right surstylus.