Megaselia triplicicristae, DISNEY, 2003

DISNEY, R. H. L., 2003, Tasmanian Phoridae (Diptera) and some additional Australasian species, Journal of Natural History 37 (5), pp. 505-639 : 588-590

Megaselia triplicicristae sp. nov.

(figure 44)

Material

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

P    : 4 males, Tasmania, Fern Tree, Grays Road , 147°15∞E, 42°57∞S (grid ref. 203474), 540 m altitude, 17 August 2000 ( RHLD —25-45-45) ( TMH, UMZC).

Etymology

The name refers to the series of three clusters of three different sizes of hairs on the left side of the male epandrium.

Diagnosis

The combination of scutellum with anterior pair of small hairs and posterior pair of bristles; mesopleuron with 6–14 fine hairs but no differentiated bristles; and costal index 0.47–0.50; takes this species to group IV of Borgmeier’s (1967a) keys. The lack of differentiated anterodorsal hairs on hind tibia and brown halteres then take it to couplet 11 on p. 206, where the choice is between a costal index>0.49 or <0.47. With the first option, the costal ratios being 2.64–3.06:1.31–1.64:1 and the costal cilia 0.09–0.11 mm long, one proceeds to M. malaisei Beyer at couplet 13. However, the entirely dark brown legs of the new species contrast with the yellow legs of Beyer’s species. With the second option one proceeds, by virtue of the brown palps, to M. politiceps Borgmeier at couplet 14; but this species has paler legs and a longer front basitarsus (two-thirds instead of about half as long as tibia). Cercus with less than nine hairs; near-dorsal hair palisade of mid tibia not quite extending half length; front basitarsus with row of ventral hairs reduced to short spinules and with anteroventral row of long spine-like hairs; and anal tube subequal in length to that of epandrium, whose left face bears a single bristle and three sets of hairs.

Male

Frons brown, broader than long, with numerous fine microsetae and 52–68 hairs. Lower supra-antennal bristles only slightly shorter than upper pair. Upper SAs as far apart as either is from an antial, which is slightly higher on frons. Antial closer to anterolateral than to upper SA and AL is a little higher on frons. Pre-ocellars slightly lower on frons than mediolaterals and all four bristles almost equally spaced. Five bristles on cheek, which progressively increase in size towards lowest, and two longer ones on jowl. Third antennal segment brown and without SPS vesicles. Palp brown with seven bristles, the longest being longer than breadth of palp, and as many fine hairs. Narrow brown labrum less than half width of third antennal segment. Brown labium broadest in basal half, as labella are unusually short. Latter with few spinules below but with dense fields of brown islets, each with its own minute hair. Thorax dark brown. Notopleuron with three bristles. Abdominal tergites brown with well-developed hairs, especially at hind margins. Hypopygium brown but with an almost white left lobe to hypandrium, and as figure 44A. Right lobe of hypandrium not developed. Tarsal segments 1–3 of front leg as figure 44B. Only segments 1–4 with posterodorsal hair palisade. Segment 5 wider and longer than 4. Hind femur as figure 44C and with longest hairs of anteroventral row of outer half a little longer than those below basal half. Fifteen to 18 differentiated but fine posterodorsal hairs on hind tibia. Wings 1.3–1.6 mm long. Vein Sc not reaching R. 1 Vein 3 with a minute hair at base. Axillary ridge with two bristles, subequal to costal cilia on middle third of costa. Veins brown, but 7 very faint. Membrane lightly tinged grey.