Megaselia thomseni, Henry & Bøggild, 2019

Henry, R. & Bøggild, Esben, 2019, Fourteen new species of scuttle flies (Diptera, Phoridae) from Denmark, Zootaxa 4543 (1), pp. 63-89 : 79-82

Megaselia thomseni sp. n.

( Figs 118–125 )

Material examined. Holotype male, DENMARK, Dk SJ, Døstrup Simested Å, 5–14.v.2016, E. Bøggild (161130517, CUMZ-8-60). Description. Male. Frons brown, clearly broader than long, with dense microtrichia. SAs and anterior row of bristles as Fig. 118 . Pre-ocellars closer together than either is from a mediolateral bristle, all being at the same level on the frons. Cheek with 5–6 bristles and jowl with 2 that are clearly longer and more robust. The antennae of the holotype are missing, the palps and proboscis as Figs 118 & 119 . Thorax brown. Two notopleural bristles and no cleft in front of these. Mesopleuron bare. Scutellum with an anterior pair of small hairs and a posterior pair of bristles. Abdominal tergites brown with moderate hairs that are clearly longer at rear of T6. Venter grayish brown, and with hairs on segments 3–6. Hypopygium as Figs 120 & 121 . Legs brown, but not dark, and the front legs more yellowish. Front tarsus ( Fig. 122 ) with posterodorsal hair palisade on segments 1–4 and 5 a little longer than 4. Mid femur and tibia as Fig. 123 , with the dorsal hair palisade of tibia extending about 0.77 times its length. Hind femur as Fig. 124 . Hind tibia with about 16 differentiated posterodorsal hairs, without anterodorsals, and spinules of apical combs simple. Wings ( Fig. 125 ) 2.2 mm long. Costal index 0.38. Costal ratios 5.4: 1.7: 1. Costal cilia (of section 3) 0.06 mm long. Vein 3 with hair at base 0.04 mm long. With 6 axillary bristles, the outermost being 0.07 mm long. Sc not reaching R1. Haltere brown.

Recognition. In the key of Lundbeck (1922) to Group VII couplet 4 where the hypopygium clearly differs from that of M. rufifrons (Wood) . It more closely resembles M. praeacuta (Schmitz) but differs in having 6, not 3, axillary bristles, different costal ratios and vein 4 originating before the fork of vein 3 instead of beyond. In the key to the males of the British species ( Disney, 1989) it runs to couplet 283, but its hypopygium is immediately distinguished from that of M. frontalis (Wood) and the latter’s longer costal index (at 0.48). However, it more closely resembles M. maura (Wood) . The latter has only 3–4 axillary bristles, as opposed to 6, and its vein 4 originates beyond the fork of vein 3, as opposed to before the fork. The hypopygia are similar but distinct (compare Figs 120 & 121 with 126 & 127).

Etymology. Named after the Danish poet Søren Ulrik Thomsen.

Figures

FIGURES 118–125. Megaselia thomseni sp. n. male. 118. front of frons, postpedicels, palps and proboscis. 119. ventral view of proboscis. 120–121. hypopygium. 122. front tarsus. 123. mid femur and tibia.124. hind femur. 125. wing.