Megaselia quasirufifrons Disney, 2020

Disney, R. Henry L. & Durska, Ewa, 2020, New Species And New Records Of Megaselia Rondani (Insecta: Diptera: Phoridae) From Wigry National Park (Poland), Annales Zoologici 70 (1), pp. 97-108 : 103-104

Megaselia quasirufifrons Disney , sp. nov.

( Figs 44–53 )

Description. (Male). In the key to the males of the species of Megaselia recorded from the British Isles ( Disney 1989) it runs to couplet 183 lead 1 M. rufifrons (Wood). It closely resembles this species. Both species are unusual in that the upper supra-antennal bristles are wider apart then the pre-ocellars ( Figs 44 & 54 ). M. rufifrons has pale postpedicels ( Fig. 55 ) and an orange brown thorax and is a little larger. Thus its wing ( Fig. 61 ) is 1.4 mm long and costal index 0.4, and hind femur 0.60 mm long and 0.18 mm maximum breadth. That this is not a case of variation within a species is indicated by fine details of the hypopygium. Thus the bristles at the tip of the anal tube’s proctiger are clearly longer than those of the cerci, but in M. rufifrons they are clearly shorter and weaker ( Figs 47 & 49 ). By contrast the hypandrial bristles of M. rufifrons are longer and more robust ( Fig. 57 ) than those of the new species. In addition the labella of the proboscis have numerous small spinules below ( Fig. 46 ), unlike M. rufifrons ( Fig. 56 ). The front tarsi ( Fig. 59 ) and hind femur ( Fig. 60 ) of M. rufifrons are similar. The species fails to key out in the rest of the world’s literature and subsequent additions, with the widely spaced upper supra-antennal bristles ruling out otherwise similar species.

Male. Frons as Fig. 44 , with dense but very fine microtrichia and upper supra-antennal bristles further apart than pre-ocellars. Cheek with 2 bristles and jowl with 2 that are longer and more robust. Postpedicels, without SPS vesicles, palps and proboscis as Fig. 45 . The labella with numerous small spinules below ( Fig. 46 ). Thorax brown, with 2 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 small hairs that are longer at rear of T6 ( Fig. 47 ). Venter gray. Hypopygium as Figs 47–50 . Legs yellowish brown to pale yellow. Fore tarsus ( Fig. 51 ) with posterodorsal hair palisade on segments 1–4 and 5 longer than 4. Dorsal hair palisade of mid tibia extends about 0.6 times its length. Hairs below basal half of hind femur clearly longer (at 0.08 mm long) than those of anteroventral row of outer half (at 0.04 mm long) ( Fig. 52 ). Hind tibia with 8–9 moderately differentiated posterodorsal hairs, without anterodorsals, and spinules of apical combs simple. Wings ( Fig. 53 ) 1.07–1.10 mm long. Costal index 0.36–0.37. Costal ratios 3.4–4.8: 1.1–1.3: 1. Costal cilia (of section 3) 0.06–0.07 mm long. Vein 3 hair 0.04 mm long. 2 unequal axillary bristles, the outermost being 0.07–0.08 mm long. Sc not reaching R1. Haltere brown.

Type material. Holotype male, Poland, Wigry National Park , in emergence trap in plot 5 with Impatients parviflora DC, IX. 2017, E. Durska leg. ( MIZ PAS, – 28-60) . Paratype male as holotype except ( UCMZ, – 28-61).

Etymology. Named after its close resemblance (quasi) to M. rufifrons (Wood) .

Figures

Figures 44–53. Megaselia quasirufifrons Disney, sp. nov. male. 44 – frons; 45 – antennae, palps and proboscis; 46 – proboscis from below; 47–48 – left faces of hypopygium; 49–50 – right face of hypopygium; 51 – front tarsus; 52 – hind femur; 53 – wing.

Figures 54–61. Megaselia rufifrons (Wood) male. 54 – frons; 55 – antennae, palps and proboscis; 56 – proboscis from below; 57, 58 – left and right faces of hypopygium; 59 – front tarsus; 60 – hind femur; 61 – wing.