Megaselia laevubrevis, DISNEY, 2003

DISNEY, R. H. L., 2003, Tasmanian Phoridae (Diptera) and some additional Australasian species, Journal of Natural History 37 (5), pp. 505-639 : 560-563

Megaselia laevubrevis sp. nov.

(figure 26)

This species has been collected in Tasmania, South Australia and Western

Australia.

Material

H  : male, Tasmania, Hobart, Sandy Bay, Acushla Court , garden, 25–26 September 1998 ( R. H. L. Disney —25-32) (TMH).

P  : 10 males, 15 females as holotype, except dates 17–26 September 1998 ( RHLD —25-24, 25, 29, 30, 32) ( TMH, UMZC, CSIRO) ; 5 males, 11 females, Hobart, Battery Point, De Witt Street , garden, 23–31 December 1991, 1–11 January 1992 ( RHLD —25-6,7, 34, 39) ( TMH, UMZC, CSIRO) . 2 males, 1 female, South Australia, Mt Freeling Stn, 3.8 km WSW Yudnamutana Bore, 30°11∞09◊S, 139°14∞34◊E, pitfall traps, 16–27 September 1998 (L. Queale —25-38) ( UMZC, South Australian Museum , Adelaide) . 3 males, Western Australia, Darling Range, Mt Helena , 14–17 June 1995 ( RHLD —25-20, 22) ( UMZC) ; male, 33°15∞S, 115°13∞E, 10–12 October 1996 (Cindy Brown, 25-10-16) ( West Australian Museum , Perth) ; female, Greenough River, Geraldton , 28°43∞S, 115°02∞E, 4–5 September 1996 (Cindy Brown, 25-16) ( UMZC) ; male and female, Jurien Bay , 30°23∞S, 115°09∞E, 17–18 August 1996 (Cindy Brown, 25-16) ( UMZC) ; 7 male, 8 females, 30°35∞S, 116°10∞E, 30°59∞S, 115°40∞E, 31°02∞S, 116°02∞E, 31°20∞S, 115°30∞E, 32°15∞S, 116°47∞E, 32°11∞S, 116°05∞E, 32°14∞S, 117°12∞E, 33°22∞S, 116°05∞E, 33°24∞S, 116°20∞E, 34°15∞S, 116°03∞E, 34°22∞S, 116°25∞E, 3–4 August, 7–8 August, 14–15 September , 10–12 October , 9–10 November 1996 (Cindy Brown, 25—10-16) ( West Australian Museum , CSIRO, UMZC) .

Etymology The name refers to the abbreviated left lobe of the hypandrium.

Diagnosis

The combination of bare mesopleuron; costal index <0.44; anterior scutellars fine but at least half the length of posterior bristles; yellow to dusky yellow haltere knob; no differentiated anterodorsal hairs on hind tibia; costal section 1>2+3; vein 3 forked; costal cilia <0.1 mm long; unequal supra-antennal bristles; and yellowish brown to dark brown femora; will take this species to couplets 22 or 29 on p. 85 or to couplets 11 or 14 on p. 93 of Borgmeier’s (1967b) keys. The female resembles M. chapmani Borgmeier (only known in the female sex) but the latter has the antial bristles nearly directly below the anterolaterals, the legs yellow and the haltere dark brown. M. curticiliata Borgmeier likewise has more yellowish legs and thorax and has vein 4 much more strongly concave towards front. M. copiosa Borgmeier and M. sulfurella Schmitz have yellow legs, apart from the dark tips to the hind femora, more yellowish antennae and much smaller anterior scutellar hairs; and likewise M. deflexilinea Beyer , which lacks the dark tips to the hind femora. The male of M. patellipyga Borgmeier is immediately distinguished by the large posterolateral lobes of epandrium. Its female is unknown. Some M. bivesicata Schmitz also run to couplet 29 on p. 85. The males are distinguished by the enlarged abdominal spiracles and the females by the extensive yellow areas on the abdominal tergites. The males of subsequently described species running to these couplets are all distinguished by having the right hypandrial lobe clearly shorter than the left or else both lobes are abbreviated. The females of these species are distinguished by having two, not three bristles on the notopleuron (however, M. laevubrevis occasionally has only two bristles on one side and in one case both notopleura only had two bristles). Other diagnostic features include male mid tarsus with segment 5 shorter than 4; labella with numerous short spinules; female with abdominal tergite 6 longer than T5 and with a small anterior median notch.

Male

Frons brown, wider than long and with fine, moderately dense, microsetae. Lower supra-antennal bristles variably, but clearly, shorter and weaker than upper pair. Anterolaterals about level with upper SAs but antials a little lower and distinctly closer to ALs than to upper SAs. Typically pre-ocellars are distinctly a little nearer together than either is from a mediolateral, and either level with mediolaterals or very slightly lower on frons. Typically with five bristles on cheek and two long, strong bristles on jowl. Third antennal segment brown and lacking SPS vesicles. Palp brown at base but otherwise yellowish brown; with 9–10 bristles of which six are relatively long. Outer face with a large irregular excavation. Greatest width of brown labrum at most 0.75× that of third antennal segment. Each labellum with at least 50 short colourless spinules below. Thorax and abdominal tergites brown. Latter with small hairs, which are only a little longer at rear of T6. Venter brownish grey with hairs below segments 3–6. Hypopygium mainly brown and as figure 26B. Legs with brown femora and tibiae, with paler tarsi, but varying from yellowish brown to dark brown. Front tarsus moderately slender and with posterodorsal hair palisade on segments 1–4 only. Segment 5 subequal to, or a little shorter than, segment 4. Near-dorsal hair palisade of mid tibia extends about four-fifths of length. At least one hair below basal half of hind femur is longer than those of anteroventral row of outer half. Wing length 1.2–1.6 mm. Costal index 0.38–0.41. Costal ratios 3.5–4.1:1.7–2.5:1. Costal cilia 0.05–0.06 mm long. Sc not reaching R. Veins brown, 1

but not dark. A small hair at base of vein 3. With two (or rarely three) axillary bristles that are a little longer and more robust than costal cilia. Membrane tinged brownish grey. Apart from part of basal quarter, the haltere knob is yellow variably tinged brown, but always paler than stem.

Female

Frons similar to male, but with up to eight bristles on cheek. Palps a little shorter with weaker bristles (typically seven to nine). Labrum larger, being about 1.1× as wide as third antennal segment. Labella a little narrower and each with <20 small spinules below. Thorax as male. Abdomen with brown, short haired, tergites. T4–T8 as figure 26A, but T7 and T8 may be more complete. Sternite 7 a long narrow bar that broadens a little at rear end, and with a few hairs. Sternite 8 at most a vague platelet surrounding the median hairs at rear of segment. Cerci about 2.5× as long as broad and with terminal hair at least as long. Internally with brown, irregularly pear-shaped, furca (S9). Dufour’s crop mechanism long, but relatively narrow, and rounded behind. With four rectal papillae. Legs similar to male. Wings 1.5– 1.8 mm long. Costal index 0.38–0.43. Costal ratios 3.4–4.5:1.6–2.7:1. Costal cilia 0.05–0.06 mm long. Otherwise it and haltere as male.

Natural history

Gravid females with 22 nearly mature eggs. In some the gut contents included tiny purplish granules plus larger irregular detrital material.