Megaselia furculae, 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 : 9-12

Megaselia furculae sp. nov.

( Figs 8–10 )

In the keys of Beyer (1965) this species runs to triplet 19 on pages 49–50, as does the previous species. It is readily distinguished from the omitted M. soluta and from M. falsoluta by the possession of bifid spinules in the apical comb of the hind tibia. Its female is further distinguished from that of M. soluta by the cerci, which are broader than long in the former but at least 3x as long as broad in M. soluta . The omitted M. bispatulata Bridarolli has five axillary bristles in contrast to the three (or rarely two) of M. furculae . Otherwise it runs out as M. dewulfi Bridarolli in Beyer’s key. It is readily distinguished from the latter by its brown, as opposed to clear yellow, abdominal venter.

Male

Frons brown, clearly broader than long, with 44–62 hairs and dense but fine microsetae and the bristles arranged as Fig. 9 . SAs robust but lower pair shorter and weaker. Cheek with 5–6 bristles and jowl with two longer ones. Postpedicels subglobose, light brown but appearing darker because of dense pubescence, without SPS. Palps yellowish brown, with five bristles and up to twice as many hairs. Labrum orange brown and about 0.6x as wide as postpedicel. Labella a little darker on top, and with numerous, densely crowded short spinules below. Each is 0.7–0.8x as wide as postpedicel, so that the two together are clearly wider than it. Thorax brown, being more chestnut brown on sides. Mesopleuron with 6–20 hairs (mean 11–12, the two sides of the same fly typically have different numbers) and 0–3 bristles (mean 2; and 0 on one side only of one specimen only). Three notopleural bristles and no cleft in front of these. Scutellum with an anterior pair of hairs (smaller than hairs in middle of scutum) and a posterior pair of bristles. Abdominal tergites brown with conspicuous hairs that at rear of T6 are clearly longer than rest ( Fig. 10 ). Venter greyish brown, and with well developed hairs below segments 3–6. Hypopygium with brown (but not dark) epandrium, a more yellowish brown hypandrium with a pale straw yellow left lobe, and similarly coloured anal tube except the cerci may be partly very lightly tinged brown, and as Fig. 10 . Right lobe of hypandrium vestigial. With four rectal papillae. Legs with coxae, femora and dorsal edge of hind tibia yellowish brown to brown, the rest being straw yellow. Fore tarsus with posterodorsal hair palisade on segments 1–5. Dorsal hair palisade of mid tibia extends almost three quarters of length. Hairs below basal half of hind femur a little longer than those of anteroventral row of outer half. Hind tibia with 10–12 differentiated posterodorsal hairs, the lowest nine being robust but the last is not stronger than the rest. Some of the spinules of apical combs bifid ( Fig. 8 ). Wings 1.6–1.9 mm long. Costal index 0.50–0.54. Costal ratios 2.9–4.0: 2.3–3.5: 1. Costal cilia (of section 3) 0.10–0.13 mm long. Hair at base of vein 3 longer than costal cilia at level of humeral cross vein. With three (or rarely only two) axillary bristles, the outer being slightly shorter than costal cilia. Sc not reaching R1. Veins yellowish brown to brown. Membrane tinged brownish grey (just evident to naked eye when viewed against a white background). Haltere with brown stem and yellow knob.

Female

Head similar to male, except the chestnut brown labrum is 1.5x wider than diameter of postpedicel, the labella are only 0.5x as wide and the palps are not quite so wide. Thorax as male. Abdominal tergites brown, except T3 is distinctly a contrasting yellowish brown, with short hairs except for a few at sides of T2 and clearly longer ones at rear of T6. The latter with a broad, but shallow emargination of its front edge. Venter brownish grey, and with hairs below segments 3–6. Sternite 7 a tall, but narrow, triangle with four hairs at its rear margin and a few shorter ones in front of these. Posterolateral lobes at rear of sternum 8 each with four bristles and then tapered, and curving towards each other, beyond these bristles. Cerci pale straw yellow and short, being about 1.4x as broad as long. With four rectal papillae. Furca a well sclerotised, irregular to subtriangular structure measuring 0.04–0.05 x 0.030–0.035 mm. Dufour’s crop mechanism about 3x as long as greatest breadth and rounded behind. Legs similar to male. Wing 1.9–2.2 mm long. Costal index 0.52–0.57. Costal ratios 3.2–4.1: 2.5–3.3: 1. Costal cilia 0.10–0.13 mm long. Otherwise wing and haltere as male.

Three of the females were gravid, with smooth eggs that measure 0.50 x 0.20 mm. The number matured at a time possibly varies with the size of the fly as indicated by the length of the hind femur. 10 eggs (HF = 0.93 mm), 12 eggs (HF = 0.87 mm) and 24 eggs (HF = 0.99 mm).

Material

HOLOTYPE male, Seychelles, Lantana, Lantana North, Malaise trap, 30 July to 1 August 2000, J. Gerlach ( CUMZ, 8­122). Paratypes, 16 males, 7 females, as holotype ( CUMZ, 122­126); 2 males, Mount Dauban, in Nepenthes pervillei pitcher, 11 August 2000, J. Gerlach ( CUMZ, 8­100); 4 males, Silhouette Island, Jardin Marron, 2000–2001, J. Gerlach ( CUMZ, 8­132, 133). Also examined (in alcohol), 168 males, 31 females as holotype; 3 males, 3 females, Silhouette Island, etc.

Figures

FIGURES 8 – 10. Megaselia furculae, male: (8) posterior face of tip of hind tibia; (9) frons, with bristles represented by their basal sockets only; (10) left face of hypopygium. Scale bars = 0.1 mm.