Helosciomyza steyskali, McAlpine, 2012

McAlpine, David K., 2012, Notes and Descriptions of Australian Helosciomyzidae or Comb-winged flies (Diptera: Schizophora), Records of the Australian Museum 64 (1), pp. 51-70 : 64-66

Helosciomyza steyskali n.sp.

Figs 19, 23

Helosciomyza ferruginea Hendel. –Steyskal & Knutson, 1979: 736 (in part, misidentifications; fig. 16 represents H. steyskali , fig. 2 apparently not); Barnes, 1981: 56–57 (in part, misidentifications; figs 13, 14 apply to H. steyskali ; Queensland record probably applies to H. bickeli ).

Type material. Holotype ♂. New South Wales: Boyd River [Morong Creek] crossing, Kanangra-Boyd National Park [c. 1200 m], 2–4.iv.2002, B.J.D., D.K.M. ( AM K264479 ). Double-mounted on micro-pin through polyporus, postabdomen in micro-vial on pin . Paratypes. New South Wales: 1♂, same data as holotype ( AM) ; 1♂, same locality, April 2002, B.J.D. ( AM) ; 3♂♂, 1 km N of Boyd River bridge, Kanangra-Boyd National Park , Oct. 2005, D.K.M. ( AM) . Australian Capital Territory: 1♂, Uriarra State Forest , Oct. 1960, D.H.C. ( ANIC) ; 2♂♂, Blundell’s Farm , Jan. 1930, March 1930, L.F.G., I.M.M. ( ANIC) .

Other material examined (localities only given). New South Wales:Alpine Creek, Snowy Mountains Highway ( ANIC). Victoria: 12 km SE of Merrijig, Mansfield district ( MV); Mount Donna Buang, near summit ( AM); Mulgrave, near Melbourne ( MV); Cape Otway ( MV). Tasmania: Flowerdale River, near Meunna ( MV); Hellyer Gorge, Waratah Highway ( AM); Lyell Highway, near Clarence River ( ANIC); Mount Field National Park ( AM).

Because certainty of identification is difficult for females, only males are included in the type series.

Description (male). Resembling H. bickeli in most characters except as indicated below. Females may agree in general characters, which may not be absolutely diagnostic.

Coloration. Antennal segment 3 orange-tawny, with small, diffuse brown dorsal zone not extending to apex, more developed than in H. bickeli , less so than in H. obliqua and H. macalpinei . Fore femur with largely tawny-orange ground colour, its anterior surface with large dark brown apical zone and broad brown sub-basal zone usually incompletely separated from apical zone, posterior surface with variable coverage of grey pruinescence and usually only indistinct brownish apical spot; fore tarsus with segment 3 dark brown on at least distal half, segments 4 and 5 entirely dark brown; hind tibia with sub-basal slightly diffuse brown zone.

Head. Height of cheek c. 0.26–0.35 of height of eye.

Thorax. Pteropleuron and hypopleuron without setulae. Wing essentially as described for H. bickeli .

Abdomen. Pleural membrane without setulae in region of spiracle 1; sternite 1 vestigial, without setulae; sternite 5 resembling that of H. bickeli ; surstylus shaped somewhat as in H. bickeli , but broader, less strongly narrowed near mid-length, more rounded distally, with similar sub-basal posterior marginal tubercle more deeply inset from outer surface of surstylus.

Dimensions. Total length 4.8–5.9 mm; length of thorax 2.3–3.2 mm; length of wing, 5.0– 6.9 mm.

Distribution. New South Wales: highlands from Boyd Plateau southwards. Australian Capital Territory: Canberra district. Victoria: perhaps widely distributed (few records). Tasmania: apparently widely distributed.

Notes

Helosciomyza steyskali is one of those species of the fuscinevris group having no setulae on the pteropleuron, hypopleuron, and abdominal sternite 1. Within this category, it differs rather markedly from H. obliqua , H. macalpinei and H. australica in the only slightly developed dark zone on antennal segment 3, but is less clearly differentiated from H. subacuta . Helosciomyza steyskali can usually be distinguished from H. subacuta by the broad brown sub-basal zone on the anterior surface of the fore femur, but the sharpest difference is in the shape of the surstylus of the male ( Fig. 23 ). Helosciomyza steyskali differs from H. bickeli (with which it has been confused under the erroneous name H. ferruginea ) in the absence of setulae on the hypopleuron and sternite 1, in the broad brown anterior zone extending near the base on the fore femur, and in the broader surstylus with an extensive tract of microtrichia.

Three of the paratypes from Boyd River vicinity are labelled “Nr dead chook” (i.e. domestic fowl).

The specific epithet refers to George C. Steyskal, who first accurately characterized and delimited the helosciomyzids (at subfamily level, 1965) and made the first review of the Australian species (1979, with L. Knutson).

Figures

Figures 19–26.(19) Helosciomyza steyskali, protandrogram.(20) H.australica, epandrium and associated structures, posterior view, semi diagrammatic, setulae omitted. (21) H. neboissi (Pelion), left surstylus, outer view, scale = 0.2 mm. (22). H. australica (Picton Lakes), left surstylus, outer view. (23). H. steyskali (Boyd River), left surstylus, outer view. (24). H. obliqua (Mount Donna Buang), left surstylus, outer view. (25). H. driesseni (holotype), left surstylus, outer view. (26). H. macalpinei (holotype), left surstylus, outer view. Figs 21–26 all to same scale. c, cercus; ep, epandrium; pbf, posterobasal foot of surstylus; ss, surstylus; s5–s8, sternites 5 to 8; t5, t6, tergites 5 and 6.