Megaselia mountfieldensis, DISNEY, 2003

DISNEY, R. H. L., 2003, Tasmanian Phoridae (Diptera) and some additional Australasian species, Journal of Natural History 37 (5), pp. 505-639 : 565-567

Megaselia mountfieldensis sp. nov.

(figure 28)

Material

H  : male, Tasmania, Mount Field National Park, Russell Falls , 11 January 1992 ( R. H. L. Disney —25-8) ( TMH).

Etymology The name refers to the type locality, Mount Field National Park.

Diagnosis

The combination of anterior scutellars being only 0.4× as long as posterior pair of bristles; mesopleuron with hairs but no differentiated bristles; hind tibia lacking differentiated anterodorsal hairs; brown haltere; costal index 0.51; costal ratios 2.99:1.68:1; costal cilia 0.09–0.10 mm long; and brown femora; takes this species to lead 2 of couplet 13 on p. 206 of Borgmeier’s (1967a) keys. M. malasei Beyer (only known in the female sex) has yellow femora, minute anterior scutellars and a wing> 3 mm long, compared with 2.1 mm in M. mountfieldensis . Subsequently described species running to this couplet include M. chaetorhoea Beyer , which, however, has several bristles on the epandrium and even longer bristles at the rear of abdominal tergite 6. M. turbata Borgmeier has yellow femora, apart from the tip of hind femur; and likewise several (mainly aquatic) species that may run to this couplet. In one with somewhat darker femora some of the spines of the hind tibial apical comb are bifid, whereas they are all simple in M. mountfieldensis . Supra-antennal bristles subequal; dark brown third antennal segment lacks SPS vesicles; labella with only a few spinules below, but with some strong hairs basally; three bristles on notopleuron; thorax, abdominal tergites and venter brown; left face of epandrium with only a few (<10) fine hairs near single long bristle near lower margin; less than nine hairs on cercus; anal tube longer than midline length of epandrium; tip of right paraphysis curves forwards ventrally; front basitarsus with rows of small spinules below; all five fore-tarsal segments with posterodorsal hair palisade and segment 5 subequal to or slightly shorter than 4; near-dorsal hair palisade of mid tibia extends about two-thirds of length; hairs below basal half of hind femur a little shorter than longest hairs of anteroventral row of distal half; no hair at base of vein 3.

Male

Frons brown, clearly broader than long and with dense microsetae. Antials about level with upper SA bristles and almost midway between latter and anterolaterals, but slightly closer to ALs, which are distinctly higher on frons. Pre-ocellars closer to each other than either is to mediolateral and slightly lower on frons. Six or seven bristles on cheek and three stronger ones on jowl. Palps yellowish brown, with five to seven strong bristles and up to as many weaker ones. Sixteen to 20 robust hairs on mesopleuron. With hairs below segments 2–6 of venter. Hypopygium brown, but with anal tube increasingly yellow distally, and as figure 28. Short left lobe of hypandrium hairless below. Front legs paler than rest. Hind tibia with 15–16 differentiated, but fine, posterodorsal hairs. Wing veins brown and membrane tinged brownish grey. Vein Sc not reaching R. Four bristles on axillary ridge clearly longer 1

than costal cilia.