Megaselia ferimpariseta, DISNEY, 2003

DISNEY, R. H. L., 2003, Tasmanian Phoridae (Diptera) and some additional Australasian species, Journal of Natural History 37 (5), pp. 505-639 : 545-548

Megaselia ferimpariseta sp. nov.

(figure 18)

Material

H  : male, Tasmania, Fern Tree, Grays Road , 147°15∞E, 42°57∞S (grid ref. 203474), 540 m altitude, 7–17 August 2000 ( R. H. L. Disney —25-44) ( TMH).

P    : 9 males, 3 females, as holotype except dates include 7 and 8 August 2000 (25-42-45) ( TMH, UMZC, CSIRO).

Etymology The name refers to the this species being nearly the same as M. impariseta . .

Diagnosis

The combination of a scutellum with a posterior pair of bristles and an anterior pair of hairs (at most as long as those at rear of scutum); mesopleuron with hairs; costal index at least 0.5; a lack of differentiated anterodorsal hairs on hind tibia; brown halteres; costal section 1 longer than 2; and costal cilia <0.17 mm long; takes most specimens to couplet 13 on p. 206 of Borgmeier’s (1967a) keys, to M. malaisei Beyer (which is only known in the female sex). However, this species has>20 differentiated posterodorsal hairs on the hind tibia, but the new species has <15. Furthermore, the female of M. ferimpariseta has some bristle-like hairs at the sides of abdominal tergite 2, whereas all abdominal tergites of M. malaisei are short haired. A few specimens of M. ferimpariseta have one or two weakly differentiated bristles at rear of hair patch on mesopleuron. If the costal cilia are at least 0.1 mm long, the further combination of a slender front basitarsus; brown abdominal tergites in female; male third antennal segment not abnormally large; a normal hypopygium; and epandrium having hairs not bristles; takes these specimens to couplet 12 on p. 203 of Borgmeier’s keys, to M. parabasiseta Bohart. The latter species, however, has anal tube longer than epandrium, which is higher than long. If the costal cilia are <0.1 mm long, specimens with a mesopleural bristle and further combination of costa being unthickened; costal index <0.6; anal tube brown; and lower SAs not being reduced to minute hairs; will run to couplet 51 on p. 205 of Borgmeier’s keys, to M. peraffinis Beyer. The latter species was perfunctorily described in less than five lines by Beyer, but it evidently differs from the new species in that its costa distinctly overreaches tip of vein 3. Further diagnostic features are near-dorsal hair palisade of mid tibia extending up to nine-tenths of its length; a small, very fine, hair at base of vein 3; hairs below basal half of hind femur longer and stronger than those of anteroventral row in distal half; and anterior scutellars weaker than hairs of mesopleuron.

Male

Frons brown, broader than long, with 38–72 hairs, and with dense but very fine microsetae. Antials a little lower than both anterolaterals and upper supra-antennal bristles, which are almost level with each other, and closer to ALs than to to upper SAs. Lower SAs bristle-like, but only 0.6–0.7× as long as upper SAs. Pre-ocellars a little closer together than either is from a mediolateral, which is slightly higher on frons. With one to three small bristles on cheek and two or three longer ones on jowl. Third antennal segment pale brown and with numerous SPS vesicles, whose diameters are at most as large as sockets of lower SAs. Palps paler, being more yellowish than pale brown, with six to eight bristles (the most apical being distinctly longer) and as many hairs. Labrum orange-brown and with greatest breadth at most 0.6× that of third antennal segment. Labella pale yellowish brown with pair of darker bands on upper face. Each has scattered spinules (<30) ventrolaterally. Thorax brown, being paler on sides. Three bristles on notopleuron. Mesopleuron with 5–18 hairs and 0–2 (usually 0) poorly differentiated bristles at rear margin. Abdominal tergites brown, with fine hairs plus stronger ones at rear margins of T 2– T 6 and one to three such hairs posterolaterally on these segments. Venter brownish grey with hairs below segments 3–6. Hypopygium with brown epandrium, a paler hypandrium, a pale yellow anal tube that is tinged brown, and as figure 18B. Right lobe of hypandrium vestigial. Legs pale yellow lightly tinged brown to yellowish brown, but with darker tip to hind femur and along the dorsal edge of hind tibia. Only first four of fore tarsal segments with a posterolateral hair palisade. Wings 1.6–2.4 mm long. Costal index 0.50–0.55. Costal ratios 2.8–4.1:2.50–3.22:1. Costal cilia 0.09–0.13 mm long. Vein Sc ends before reaching R. Two or three 1

(usually three) bristles on axillary ridge. Veins brown. Wing membrane greyish brown (clearly evident to naked eye).

Female

Head similar to male, except labrum is darker and broader (being about 1.3× as wide as third antennal segment) and each labellum has <15 spinules below but with five teeth on inner face adjacent to glossa. Thorax as male, but anterior scutellars slightly longer and mesopleuron with 13–22 hairs plus 0–3 poorly differentiated bristles. Abdomen with brown tergites with fine hairs, which are longer at rear of T 6 and two to four are longer still on sides of T 2. The widths T 1– T 5 greatly exceed their lengths, but diminish gradually from T 2 to T 5. T 6 is about 1.3× as broad as long and has a median emargination of front margin about half as wide as length of tergite and rear margin only about 0.2× as wide as length; and with 15–20 hairs of which posterolaterals are clearly longer and stronger. Sternite 7 and posterolateral lobes of sternum 8 as figure 18A. Cerci pale yellow,>3× as long as broad, and with about 10 hairs of which the pre-apical posterior (inner) one is clearly longer. Internally Dufour’s crop mechanism is ovoid, but posterior margin is a little truncated and almost straight, with length about 1.3–1.4× greatest breadth; with four rectal papillae and no sclerotized furca evident. Wing length 2.0–3.0 mm. Costal inde× 0.54–0.56. Costal ratios 2.98–3.35:2.57–2.66:1. Costal cilia 0.10–0.15 mm long. Otherwise as male.

Natural history One female had three mature eggs, which measure 0.67–0.71× 0.25–0.30 mm.