Chasmia queenslandensis, Daniels, Greg, 2011

Daniels, Greg, 2011, A new Australian species of Chasmia Enderlein (Diptera: Tabanidae: Diachlorini), a genus newly recorded from Australia, Zootaxa 2906, pp. 61-65 : 61-64

Chasmia queenslandensis sp. n.

( Figs 1–11 )

Diagnosis. A small, compact, orange-yellow species with abdominal segments 4–6 brownish black, yellow legs and hyaline wings.

Type material. Queensland. Holotype Ƥ, Bamaga-Capt. Billy Ck Rd jnct, 16 km NE of Heathlands H.S., 160 m, 11°41'S, 142°42'E, 17.iii.1992, G. Daniels and M.A. Schneider, (Queensland Museum). Paratypes: 2 Ƥ, same data as holotype except 13.iii.1992; 3 Ƥ, same data as holotype; 1 3, 2 Ƥ, Gunshot Ck, 13 km NW of Heathlands H.S., 80 m, 11°43'S, 142°28'E, 21.iii.1992, G. Daniels and M.A. Schneider; 2 33, same data as previous specimens except mv lamp; 3 Ƥ, same data as previous except 21.iii.1992 and not mv lamp; paratypes in Queensland Museum and Australian Museum.

Description. Female. Body length 6.1–8.0 mm, body mostly bright orange-yellow. Eyes (in freshly collected specimens) red-brown. Frons narrow, index 5.9–6.5, dark brown to blackish, mostly filled with blackish-brown callus; ocellar tubercle inconspicuous, elongate, shining dark brown to blackish; subcallus and parafacial pale yellow, face orange-yellow; setae on parafacial black, inconspicuous; gena with long black setae; antennal scape and pedicel yellow, basal flagellomere orange-yellow, distal flagellomeres brown, stylus brown; palpus yellow, setae admixed yellow and black. Mesonotum and pleuron entirely bright orange-yellow, with yellow setae. Fore femur yellow basally, darker distally, mid and hind yellow; fore tibia brownish yellow, mid and hind yellow. Wings hyaline, costal cell slightly darkened basally; stigma light yellowish; vein R4 angulate. Abdomen with segments 1–3 shining bright orange-yellow, segment 3 sometimes irregularly darker in median zone; segments 4–6 shining brownish black; apical segments variably paler but sternite 8 and cercus always yellowish.

Male. Paler than female, especially abdomen; facial area sometimes more yellowish; upper eye facets markedly enlarged; ocellar tubercle narrow but distinct; abdomen diffusely darkened, at most apically on tergite 3 and entirely so on tergites 4–6. Body length 7.5–8.0 mm.

Etymology. The specific name refers to Queensland, the Australian state in which the specimens were collected.

Comments. The tribe Diachlorini was the only group of Australian tabanids not to be revised by Mackerras. He did, however, produce an interim catalogue of the Australian species ( Mackerras 1959) and, in the introductory section, referred to six undescribed Australian species of Cydistomyia Taylor with no further reference to these species made in the body of the paper. Mackerras and Spratt (2008) revised Lissimas Enderlein and Cydistomyia , describing 17 new species of the latter. Neither Mackerras nor Spratt seem to have been aware of the presence of Chasmia in Australia.

Chasmia queenslandensis sp. n. runs to C. subhasta (Oldroyd) in Mackerras' (1964) key to New Guinea species but the former differs in having black setae on the gena; a less conspicuous ocellar tubercle; and a wider callus. Chasmia queenslandensis sp. n. can be distinguished from all other Australian species of Diachlorini and in particular species of Cydistomyia by its combination of small size (6–8 mm); muscoid-like appearance; a well defined ocellar tubercle and a closed but not petiolate cell cu p.

Other Australian tabanid species that resemble muscoid flies can be found in Scaptia (Myioscaptia) Mackerras. Chasmia queenslandensis sp. n. can be readily distinguished from this group by its orange colour, small size, absence of ocelli and antennal structure.

Specimens were taken in monsoon rainforest along the Great Dividing Range and on the edge of riverine rainforest at Gunshot Creek, Cape York Peninsula. Most specimens were collected in malaise traps and a few were taken at mercury vapour lamps. None was attracted to humans.

Figures

FIGURES 1 – 6. Chasmia queenslandensis female. (1) Head, anterior view; (2) Head, lateral view; (3) Antenna; (4) Palpus; (5) Wing; (6) Habitus.

FIGURES 7 – 11. Chasmia queenslandensis male. (7) Head, anterior view; (8) Head, lateral view; (9) Antenna; (10) Palpus; (11) Habitus.