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

Disney, R. Henry L., 2006, Eight new species of Megaselia Rondani (Diptera: Phoridae) from the United Arab Emirates, Oman, and Yemen, Zootaxa 1371, pp. 1-21 : 13-15

Megaselia nudihalterata sp. nov.

( Figs 21 – 22 )

In Beyer’s (1965) keys this species runs to couplet 5 on page 56 or couplet 10 on page 57, depending on the length of the costal index. This whole section from couplet 5 onwards is far from satisfactory as he not only omitted species described by Collin (1912) but more than a dozen species have been described since. However, the majority of the species running to this section only have two bristles on the notopleuron. Several of those with three bristles, like this species, are discussed with the further addition of M. gallagheri (see above), where it is pointed out that M. nudihalterata along with M. agarici and M. nectama and are immediately distinguished by their very pale vein 7. The latter two species are immediately distinguished by their pale yellow haltere knobs as opposed to the brown knobs of the new species. At low magnifications the dusky abdominal venter in both sexes will exclude several species of this complex as do the robust feathered bristles on the epandrium of the male.

Etymology

Named after its resemblance to the widely distributed mushroom pest M. halterata (Wood) but lacking the conspicuously hairy abdominal venter of the latter.

Male

Frons brown, broader than long, with 32 – 49 hairs, dense but very fine microsetae and bristles positions very similar to M. necmera ( Fig. 14 ). Upper SAs robust but lower pair less than half as long and much finer. Cheek with 2 – 3 bristles and jowl with two longer ones. Postpedicels subglobose, brown, with larger than usual bulbous peg sensilla (about 0.005 mm in diameter) but evident as pale spots on surface at low (e.g. x50) magnifications; and with some SPS vesicles that are variable in size but the largest are subequal to the diameters of sockets of the upper SAs. Palps straw yellow, with six bristles (3 – 4 being long and 2 – 3 being short) and 2 – 5 hairs. Labrum coloured as palps and about 0.5 – 0.6x as wide as postpedicel. Labella also pale and with only about a dozen short spinules below each. Thorax brown, being paler on sides. Mesopleuron bare. Three notopleural bristles and no cleft in front of these. Scutellum with an anterior pair of hairs (subequal to those at rear of scutum) and a posterior pair of bristles. Abdominal tergites brown with the hairs at rear of T6 a little longer than rest ( Fig. 22 ). Venter yellowish grey and with hairs below segments 5 and 6, but those below 3 and 4 are mostly, or entirely, reduced to minute hairs (like those to the rear of the spiracle on segment 6 — Fig. 22 ). Hypopygium brown, including the paler anal tube, and as Fig. 22 . Right lobe of hypandrium vestigial. With four rectal papillae. Legs straw yellow, apart from brown patch on mid coxa, but the hind femur gradually darkens to a light brown in outer half. Fore tarsus with posterodorsal hair palisade on segments 1 – 4, and segment 5 is a little longer than 4. Dorsal hair palisade of mid tibia extends about half of length. Hairs below basal half of hind femur longer than those of anteroventral row of outer half. Hind tibia with 11 – 16 differentiated, but fine, posterodorsal hairs, except at least one in the third quarter is/are stronger than the rest. Spinules of apical combs simple. Wings 1.2 – 1.4 mm long. Costal index 0.29 – 0.35. Costal ratios 4.7 – 6.2: 1.0 – 1.6: 1. Costal cilia (of section 3) 0.08 – 0.11 mm long. A small hair at base of vein 3 (except in one specimen it is absent on one wing). With two axillary bristles, the outer being subequal to costal cilia. Sc pale and fading away well before R1. Veins pale yellowish grey, except 7 is very pale and difficult see at low magnifications. Membrane only very lightly tinged grey. Haltere brown.

Female

Head similar to male except labrum about 0.8x wider than diameter of postpedicel and light brown. Thorax as male. Abdominal tergites brown, but T8 paler than the rest. T5 – T7 as Fig. 21 . Venter as male. Sternite 7 absent. Posterolateral lobes at rear of sternum 8 only indicated by each having a patch of about eight hairs. Apical hairs of hypoproct scarcely differentiated from those along its sides. Cerci pale brown and about twice as long as broad. Furca not evident. The pale Dufour’s crop mechanism is almost 4x as long as its greatest breadth and is rounded behind. Legs similar to male but mid and hind femora and tibiae in part darker, being tinged brown, especially the hind femora. Wing as male except length is 1.4 – 1.5 mm. Costal index 0.31 – 0.33. Costal ratios 6.4 – 7.2: 1.3 – 2.0: 1. Costal cilia 0.09 – 0.10 mm long. Otherwise it and haltere as male.

Material

Holotype male, Yem en, 12 km N.W. Manakhah, Malaise trap, 3.vii – 2.viii.2001, A. van Harten ( CUMZ, 2 – 156). Paratypes, 4 males, as holotype ( CUMZ, 2 – 156, 157, 160); 1 male, Ar Rujum, Malaise trap, 15.i – 9.iv.2001, A. v H. ( CUMZ, 32 – 115). 6 males, Oman, Wattayeh, 1.iii – 7.iv.1988, M. J. Ebejer & M. D. Gallagher (National Museum of Wales, CUMZ, 5-145-147). 1 female, United Arab Emirates, NARC, near Sweiham, light trap, 2 – 30.iv.2005, A. van Harten ( CUMZ, 32 – 142); 3 males, Sharjah Desert Park, light trap, 29.III. – 6.IV.2005, A v H. ( CUMZ, 32 – 132, 133); 1 female, 6 – 30.iv.2005 ( CUMZ, 32 – 144); 2 males, Wadi Warayah, 12 – 14.iii.2005, T. Pape ( CUMZ, 32 – 138, 139).

Figures

FIGURES 21 – 22. Megaselia nudihalterata (21) female, abdominal tergites 5 – 7; (22) male, left face of hypopygium. Scale bars = 0.1 mm.

FIGURES 14 – 17. Megaselia necmera (14) male frons, with bristles represented by their basal sockets only; (15) female furca; (16) left face of male hypopygium (17): female Dufour’s crop mechanism.