Gondwanodromia thredbo, Sinclair & Saigusa, 2022

Sinclair, Bradley J. & Saigusa, Toyohei, 2022, A New Aquatic Associated Genus of Trichopezinae from the Southern Hemisphere (Diptera: Empidoidea: Brachystomatidae), Records of the Australian Museum (Rec. Aust. Mus.) 74 (3), pp. 75-98 : 91-92

Gondwanodromia thredbo sp. nov.

urn:lsid:zoobank.org:act:4931052D-FBB4-44A9-8232-2AF83DFE264F

Figs 39, 40 , 50

Holotype ♂, labelled: “ AUST: NSW: Kosciusko/ NP, Dead Horse Gap [36°31'21"S 148°15'50"E]/ 28.xi.1994, 1500m / B.J. Sinclair / ex. Thredbo River ”; “ HOLOTYPE / Gondwanodromia / thredbo/ Sinclair & Saigusa” ( AMS K.594168).

Diagnosis. The species is readily distinguished by bare eyes, male fore tibia with pair of stout anteroventral setae arising from prolongation, mid tibia somewhat swollen apically with pair of peg-like ventroapical setae and epandrium deeply V-shaped with anterior half one-third height of posterior half.

Description. Wing length 3.7 mm. Male. Head. Eye bare, without ommatrichia. Frons brown. Face with bluish pruinescence; broad, subequal to width of antennal socket. Ocellar setae long and divergent, inserted anteromedial to lateral ocelli; one short posterior seta; 3 vertical setae, outer seta arched over margin of eye, shorter than ocellar seta; occipital setae shorter and thinner than vertical setae. Antenna ( Fig. 39 ) with scape nearly subequal in length with pedicel; postpedicel nearly 1.5× height of eye. Proboscis longer than head height; palpus brown, two-thirds length of proboscis.

Thorax. Dark brown, with thin blue pruinescence laterally on scutum, prescutellum, scutellum and pleura. Antepronotum with several pairs of long setae, strongly laterally.Acrostichal setae uniserial with setae alternating in direction, more than half length of dorsocentral setae; 8 uniserial dorsocentral setae, anterior seta longer and set off laterally from row; 1 long postpronotal seta and 1–2 shorter anterior setae; 1 presutural supra-alar seta; 3 notopleural setae, middle seta stronger and twice length of other setae; 2 postsutural supra-alar setae; 1 postalar seta; 2 pairs of scutellar setae, outer pair slightly more than half length of inner pair. Laterotergite with 4–5 setae. Wing ( Fig. 39 ). Infuscate; basal costal seta long and slender. Halter pale brown. Legs. Coxae brown with bluish pruinescence, apical setae brown; remaining leg segments increasingly darker apically. Femora long and slender; fore femur somewhat inflated, with posteroventral row of slender setae; mid femur with row of short anteroventral and row of longer posteroventral setae; hind femur with erect dorsal setae near base. Fore tibia produced anteroventrally, bearing pair of apical spine-like setae. Mid tibia expanded somewhat subapically with rows of short ventral setae; pair of peg-like apicoventral setae, shorter than width of tibia. Hind tibia with stout dorsal and ventral setae, shorter than width of tibia. Mid tarsomere 1 with row of strong posteroventral setae; without erect posteroventral seta at basal fifth.

Abdomen. Tergite 6 with long dorsal setae on posterior half, nearly as long as tergite, setae longer than on other tergites. Sternite 7 prolonged posterolaterally into narrow lobe overlapping anterior margin of sternite 8. Tergite 8 trapezoidal, half-length of sternite 8; posterior margin wider than anterior margin, bearing numerous setae, denser on lateral margin; sternite 8 trapezoidal, with setae longer than anterior sternites, especially along posterior margin. Terminalia (undissected) ( Fig. 40 ). Cercus thinly sclerotized narrow and tapered apically [apex obscured by precipitate]. Epandrium deeply V-shaped laterally, anterior half one-third height of posterior half; without dorsal bridge. Surstylus paired; anterior surstylus smoothly sclerotized, without microtrichia, apical third expanded into triangular plate with long, spine-like preapical seta directed anteriorly; posterior surstylus produced apically into thinly sclerotized, setose lobe with marginal setae. Hypandrium tubular, arched and recurved apically. Phallus not observed.

Female. Unknown.

Etymology. The species is a noun in apposition, named after the river upon which the holotype was collected.

Distribution. This species is known only from the type locality ( Fig. 4 ) in Kosciusko National Park, New South Wales, Australia ( Fig. 50 ).

Figures

Figures 37–40.Australian and New Zealand species of Gondwanodromia, lateral view:(37) G. mutabilis (Collin), male habitus (abdomen dissected), scale bar = 1.0 mm; (38) G. tasmanica sp. nov., female habitus, scale bar = 0.75 mm; (39) G. thredbo sp. nov., male habitus, holotype, scale bar = 0.75 mm; (40) G. thredbo sp. nov., male terminalia, scale bar = 0.25 mm.Abbreviations: a sur – anterior surstylus; epand – epandrium; hypd – hypandrium; p sur – posterior surstylus.

Figures 50–52. Distribution of Gondwanodromia: (50) Australian species; (51) New Zealand species; (52) South American species.

Figures 1–4. Photographs of living Gondwanodromia and habitats:(1)Arroyo Torrontegui,Argentina; (2)Arroyo Torrontegui,Argentina, with collector Mika Sugimoto; (3) female, Altos del Lircay, Chile (photograph © Steve Marshall); (4) Dead Horse Gap trail, Kosciusko National Park, Australia; November 1994.