Megaselia pseudomera, Disney, R. Henry L., 2006

Disney, R. Henry L., 2006, Nine new species of Megaselia Rondani (Diptera: Phoridae) from the Seychelles, Zootaxa 1210, pp. 1-25 : 16-19

Megaselia pseudomera sp. nov.

( Figs 22 , 29, 30 )

In the keys of Beyer (1965) this species runs to couplet 3, lead 2, on page 56, to M. lilliput Beyer , which is only known from a single female from Angola. The omitted M. mera (Collin) (see above), also described from a single female only, will run to the same point. Like M. lilliput the new species has dark brown haltere knobs and darker brown postpedicels than M. mera . Its costal index is a little longer (>0.37) than that of the female of M. lilliput , in which it is only 0.34. Also Beyer’s species supposedly lacks the Sc, which is present but faint in M. mera and the new species, and its posterodorsal hairs of the mid tibia are differentiated in the lower half only, unlike M. mera and the new species. The male of M. mera and the new species can be readily distinguished as follows. The following features characterise M. pseudomera , thorax entirely brown; haltere knob as dark as stem; the pair of hypandrial bristles as strong as those at rear of epandrium below the anal tube. By contrast in M. mera the thorax is partly yellowish to orange brown; the haltere knob is yellowish brown, and the hypandrial hairs are clearly weaker than those at the rear of the epandrium below the anal tube. The same characters distinguish the species from M. jorgensis , which is distinguished from M. mera above.

Etymology

The name refers to its close resemblance to M. mera .

pseudomera male; (23) M. vitiomera male. Scale bar = 0.1mm.

Male

Frons brown, with 64–84 hairs and dense but fine microsetae. Back of head also with dense microsetae. SAs robust and unequal, the lower pair being distinctly shorter. Bristles arranged as in Fig. 29 . Cheek with 3–4 bristles and jowl with 2 longer ones. Postpedicels subglobose, pale yellowish brown (but apex appears darker because of the dense pubescence) and without SPS vesicles. Palps pale straw yellow, with 5 bristles and as many hairs. Labrum ( Fig. 22 ) a little darker than palps and about 0.7x as wide as postpedicel. Labella ( Fig. 22 ) a little darker on top, and with dense fields of short spinules below. Thorax brown, being paler on sternopleuron. Mesopleuron bare. Two notopleural bristles and no cleft in front of these. Scutellum with an anterior pair of hairs (shorter than hairs at rear of scutum) and a posterior pair of bristles. Abdominal tergites brown with the hairs at rear of T6 longer than rest ( Fig. 30 ). Venter brownish grey, and with hairs below segments 5–6, those on 3–4 being reduced to microsetae. Hypopygium brown, with pale anal tube lightly tinged brown, and as Fig. 30 . Right lobe of hypandrium vestigial. With two rectal papillae. Legs straw yellow but outer half of hind femur increasingly brown towards tip and there is a brown patch on the mid coxa. Fore tarsus with posterodorsal hair palisade on segments 1–5, and 5 is a little longer than 4. Dorsal hair palisade of mid tibia extends about three quarters of its length. Some hairs below basal half of hind femur clearly longer than those of anteroventral row of outer half. Hind tibia with 7–10 differentiated posterodorsal hairs. Spinules of apical combs simple. Wings 1.0– 1.2 mm long. Costal index 0.38–0.40. Vein 3 unforked. Costal ratios 1.6–2.3: 1. Costal cilia (of section 2) 0.5– 0.07 mm long. Hair at base of vein 3. With 2 axillary bristles, the outer being longer than costal cilia. Sc not reaching R1. Veins pale brownish grey, but 7 very pale. Membrane only very lightly tinged grey. Haltere with brown stem and knob.

Material

HOLOTYPE male, Seychelles, Silhouette island, Grande Barbe, Acrostichum marsh, 3–10 June 2001, J. Gerlach ( CUMZ, 8­137). Paratype, 1 male, as holotype.

Figures

FIGURES 18 – 23. Megaselia species, labrum and labella of proboscis from above. (18) M. jorgensis female; (19) M. jorgensis male; (20) M. mera male; (21) M. mera female; (22) M.

FIGURES 29, 30. Megaselia pseudomera, male: (29) frons, with bristles represented by their basal sockets only; (30) left face of hypopygium. Scale bars = 0.1 mm.