Megaselia falsum Disney, 2019

Saifi, Mounir, Disney, R. Henry L. & Doumandji, Salaheddine, 2019, A new species and new records of scuttle flies (Diptera: Phoridae) from Algeria, Zootaxa 4619 (1), pp. 189-194 : 190-191

Megaselia falsum Disney n. sp.

The association of the females with the male was based on their co-occurrence plus details of critical measurements of wing features etc.

Material examined. Holotype male, ALGERIA, Ain Solane , Bordj BouArrenji, 12.iv.2015, Mounir Saifi ( UCMZ, 26-87). 8 female paratypes, same locality, 11; 12.iv.2015, M.S. ( ENSA & UCMZ, 26-87 & 88).

Male. Frons similar to female ( Fig. 7 ) and likewise largely lacking fine microtrichia. Cheek with 5 bristles and jowl with 2 that are longer and more robust. Postpedicels, palps and proboscis as Fig. 1 . 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 small hairs, including at rear of T6 ( Fig. 4 ). Venter gray, and with only a few small hairs on segments 4 to 6 ( Fig. 2 ). Hypopygium as Figs 2–4 . Legs yellowish brown with paler tarsi and distal half or more of front coxa. Fore tarsus with posterodorsal hair palisade on segments 1–4 and as female ( Fig. 13 ). Dorsal hair palisade of mid tibia extends about 0.45 times its length ( Fig. 5 ). Hind femur as Fig. 6 . Hind tibia with a dozen moderately differentiated posterodorsal hairs but the most distal is longer and more robust, without anterodorsals, and spinules of apical combs simple. Wings similar to female ( Fig.15 ) 1.30 mm long. Costal index 0.31. Costal ratios 5.1:1.0: 1. Costal cilia (of section 3) 0.05–0.06 mm long. Hair at base of vein 3 small. With 2 unequal axillary bristles, the longer, outer, being 0.06 mm long. Sc not reaching R1. Haltere knob. pale.

Female. Frons as Fig. 7 . Postpedicel and palp as Fig. 8 . Proboscis as Fig. 9 . Otherwise head similar to male. Thorax as male.Abdominal tergites as Figs 10 & 11 . Venter gray, and with only a few isolated hairs below segments 3 and 4, a few on 5 a single row at the rear of 6. Sternite 7 and posterolateral lobes at rear of sternum 8 as Fig. 12 . Cerci pale gray and almost 3 times as long as broad, with half a dozen hairs and a terminal bristle almost 1.5 times as long as cercus. Furca not evident. Dufour’s crop mechanism pale and bilobed behind, about 0.17 mm long of which the lobes represent 0.06 mm of this length. Legs similar to male, with front tarsus as Fig. 13 and hind femur as Fig. 14 . Wing as Fig. 15 , being 1.1–1.3 mm long. Costal index 0.31–0.32. Costal ratios 3.8–5.1: 1.00–1.15: 1. Costal cilia 0.05–0.06 mm long. Outer axillary bristle 0.08 mm long. Otherwise it and haltere as male.

Etymology. Falsum means fraud, which refers to the male so closely resembling two other species whose females are readily distinguished.

Recognition. In the keys to the males of the British Megaselia species ( Disney, 1989) it runs to triplet 218, but its hypopygium excludes these species. In the keys to the species of Arabia (Disney, 2009) the male runs to couplet 74, where neither option fits. The female runs to couplet 59, lead 2 but abdominal tergites 4–8 are clearly different. A note suggests the unknown female of M. savannae Disney is likely to run to this point. However not only does the male hypopygium of M. savannae differ from that of M. falsum , but it has much longer hairs at the rear of tergite 6. The hypopygium of M. falsum places it in complex of species from elsewhere which have very similar hypopygia but distinctive females. This complex was reviewed by Disney (2006). In this key the male runs to couplet 7, to M. oxybelorum Schmitz and M. parvula Schmitz. The hypopygia ( Figs 16–19 ) are extremely similar and likewise that of M. falsum ( Figs 2–4 ). A consistent, but very small difference, is the shorter hairs at the rear of tergite 6. The female of M. falsum runs to couplet 11, lead 2 to M. brevior (Schmitz) but its abdominal tergite 6 is not tapered like that of M. falsum .

Figures

FIGURES 7–15. Megaselia falsumn. sp. female. 7. Frons. 8. Postpedicel and palp. 9. Proboscis. 10. Abdominal tergites 3 to 6. 11. Tergites 6 and 7. 12. Sternite 7 and lobes at rear of sternum 8. 13. Front tarsus. 14. Hind femur. 15. Wing.

FIGURES 1–6. Megaselia falsum n. sp. male. 1. Postpedicels, palps and proboscis. 2. Left face of hypopygium. 3. Right face of tergite 6 and hypopygium. 4. Right face of tergite 6, epandrium and anal tube. 5. mid tibia. 6. hind femur.

FIGURES 16–19. Megaselia males of species whose hypopygia closely resemble that of M. falsum. 16–17. M. oxybelorum. 18–19. M. parvula.