Megaselia multispinulosa, DISNEY, 2003

DISNEY, R. H. L., 2003, Tasmanian Phoridae (Diptera) and some additional Australasian species, Journal of Natural History 37 (5), pp. 505-639 : 567-569

Megaselia multispinulosa sp. nov.

(figure 29)

Material

H  : male, Tasmania, Fern Tree, Grays Road , 147°15∞E, 42°57∞S (grid ref. 203474), 540 m altitude, 6 August 2000 ( R. H. L. Disney —25-41) ( TMH).

P    : 4 males, 1 female, as holotype except 7–17 August 2000 (25-42-44) ( UMZC, TMH).

Etymology The name refers to the dense spinules below the male labella.

Diagnosis

In the keys of Borgmeier (1967a) the combination of scutellum with posterior pair of bristles and anterior pair of small hairs (which are weaker than, and at most as long as, those at rear of scutum); mesopleuron with 5–16 small hairs plus a clearly differentiated bristle at rear margin that is shorter than humeral bristle; costal index>0.5; costal cilia 0.16–0.18 mm long; hind tibia without differentiated anterodorsal hairs; haltere knob brown in male but yellow in putative female; abdominal tergites brown in both sexes; front basitarsus at least 7× as long as broad in both sexes; male third antennal segment not obviously enlarged; and hypopygium of typical form; takes the males of this species to couplet 11 on p. 202; to M. setipyga Borgmeier , a synonym of M. chaetorhoea Beyer. The latter, however, has dark brown antennae and hairs below basal half of hind femur shorter than those of anteroventral row of the distal half. In the new species they are subequal in length. The putative female runs to couplet 16 (p. 203), where the darkened dorsal edge of the hind tibia indicates resemblance to M. lineatipes Borgmeier. However , the darker and longer wings (> 2 mm, as opposed to <2 mm) and longer costal cilia (> 0.14 mm, as opposed to <0.13 mm) will distinguish the new species. Each cercus with eight hairs in both sexes; near-dorsal hair palisade of mid tibia extends 0.75–0.80× its length; male labella enlarged and with dense fields of small spinules below; left hypandrial lobe hairy to tip; third antennal segment lacks SPS vesicles; posterolateral lobes of female abdominal sternum 8 short with almost straight hind margins; hind femur brownish yellow gradually darkening towards tip; costal section 1 shorter than section 2.

Male

Frons brown, broader than long; with dense but very fine microsetae, and 56–84 hairs. Antial bristles about midway between anterolaterals and upper supraantennals or closer to ALs, but slightly lower on frons. ALs slightly higher on frons than upper SAs. Lower SAs only about two-thirds as long as upper pair and not as robust. Pre-ocellars a little closer together than either is from a mediolateral and all four bristles in an almost straight transverse row. Three or four small bristles on cheek and three or four longer and more robust ones on jowl. Third antennal segment yellowish brown to pale brown, with brown arista. Palps pale yellowish brown to brownish yellow, with six to eight bristles and as many hairs. Greatest breadth of brown, subtriangular, labrum at most only two-thirds that of third antennal segment. Thorax brown, with three bristles on notopleuron. Abdominal tergites with well-developed hairs, which are longest at sides and hind margins. Hypopygium brown, with paler anal tube (especially tip of proctiger) and as figure 29B. Right lobe of hypandrium vestigial. Legs mainly yellowish brown to brownish yellow in parts. All five segments of fore tarsus with a near-dorsal hair palisade. Hind tibia with about a dozen differentiated posterodorsal hairs, but basal five or six weak, and one below middle is spine-like (being longer than preapical). Wing length 2.1–2.6 mm. Costal index 0.53–0.56. Costal ratios 2.27–2.44:2.53–2.72:1. Vein Sc ending before R. Strong hair at base of vein 3. Four 1

bristles on axillary ridge as long and as robust as costal cilia. Veins brown and membrane tinged brownish grey (evident to naked eye).

Putative female

Apart from yellowish knob to haltere, the single female specimen closely resembles the male. Frons similar to male but with 80–90 hairs and PO bristles distinctly closer together than either is from a mediolateral bristle. Labrum more heart-shaped and its greatest breadth about 1.2× that of third antennal segment. Labella with far fewer spinules, which are restricted to outer faces, but with conspicuous teeth on inner faces adjacent to glossa. Abdominal tergites progressively narrower from T 2 to T 6, with small hairs except at side and rear margins and especially posterolaterally. T 5– T 7 as figure 29A. Venter grey with more yellowish intersegmental bands and with small hairs below on segments 3–6 and on flanks of 6. Each posterolateral lobe of sternum 8 with three bristle-like hairs and longish pubescence overreaching hind margin. Cercus just over twice as long as broad, pale yellow, and with pre-apical hair clearly longer than rest. Internally, Dufour’s crop mechanism is about 3.5× as long as broad and rounded posteriorly; with four rectal papillae; but no sclerotized furca evident. Legs similar to male. Wings 2.6–2.7 mm long. Costal index 0.54–0.55. Costal ratios 2.28:2.49:1. Otherwise as male.