Ommatomyia, Scabrough & Tomasovic, 2010

Scabrough, Aubrey G. & Tomasovic, Guy, 2010, Ommatomyia, a new genus from Vietnam (Diptera: Asilidae: Ommatiinae), Zootaxa 2366 (1), pp. 46-54 : 47-49

Ommatomyia gen. nov.

( Figs 1, 3–12 )

Type species: Ommatomyia cera sp. nov., by present designation.

Diagnosis. Small, slender Ommatiinae with largely dark body, brownish-yellow or yellow pleuron and legs, and the following combination of characters: Head: Narrow face, with two vertical rows of bristles extending from just below antenna to frontoclypeal suture [=oral margin of other authors]; mystax with pale setae and bristles. Antennal stylus three-segmented, largely bare, plume abbreviated and confined to apical segment; basal segment as long as scape, pedicel, and flagellum combined; median segment contrastingly short; apical segment about half as long as basal segment; setae short, aligned on each side (bilateral) in a ventrolateral position, becoming progressively longer apically; pedicel oval, wider than scape or flagellum in lateral view ( Fig. 1 ). Dorsal postocular bristles proclinate. Thorax: Dorsocentrals weak, seta-like. Scutellar groove prominent. Anepimeral bristle absent. Posterior metacoxal bridge sclerotized. Wing ( Fig. 3 ): Cell r 1 closed, stalked apically. Legs: Slender, ventral bristles weak, seta-like. Basal tarsomere of hind tarsus as long as apical 4 tarsomeres combined. Male terminalia ( Figs. 4–12 ): Cercus short, barely visible in dorsal view, largely concealed by epandrium; ventral lamella erect, much wider than paired cerci, convex. Gonocoxite as long as epandrium, digitate apically. Hypandrium simple, rectangular, wider than long with distal margin truncate. Female terminalia ( Fig. 12 ): Spermathecae filamentous.

Discussion. Justification for establishing this genus is based largely on the characters of the stylus ( Fig. 1 ). The stylus of a typical Ommatiinae is undivided and has long setae (plume) aligned ventrally along most or all of its length. Each seta alternates in position slightly to the right or left of each preceding seta. Thus forming two rows of setae, rarely one ( Fig. 2 ). Setae in the bilateral plume of Ommatomyia alternates similarly. The three-segmented stylus, bare with an abbreviated plume, and the long basal tarsomere, as long as the apical four tarsomeres combined, distinguish the new genus. The long filamentous spermatheca without an obvious terminal capsule or valve further distinguish the female. Spermathecae in the remaining genera are usually significantly shorter in length and with prominent terminal capsules and basal valves.

Etymology. Greek, Ommatomyia , combination, referring to an Ommatius -like fly. Monotypic. Gender female.

Distribution. Vietnam, Nuiba National Park near Dalat, Lam Dong Province.

Figures

FIGURES 1–3. Ommatiinae antennae & wing. 1. Ommatomyia cera gen. et sp. nov., antenna; 2. Ommatius anisoramus Scarbrough & Hill, 2000a, antenna; 3. Ommatomyia cera, sp. nov., wing. Abbr. flgm=flagellum, ped=pedicel, scp= scape, vein R4+5, cells m3, r4.

FIGURES 4–8. Male terminalia, Ommatomyia cera gen. et sp. nov., 4–6. Dorsal, lateral, & ventral views; 7. Gonostylus; 8. Aedeagus. Abbreviations: aed= aedeagus, aed apod= aedeagal apodeme, aed sh=aedeagal sheath, cerc= cercus, epand=epandrium, ej apod= ejaculatory apodeme, goncx= gonocoxite, gonst= gonostylus, hypd= hypandrium, st7= sternite 7, vl =ventral lamella.

FIGURES 9–12. Male terminalia, Ommatomyia cera gen. et sp. nov., 4–6. Dorsal, lateral, & ventral views; 7. Gonostylus; 8. Aedeagus. Abbreviations: aed= aedeagus, aed apod= aedeagal apodeme, aed sh=aedeagal sheath, cerc= cercus, epand=epandrium, ej apod= ejaculatory apodeme, goncx= gonocoxite, gonst= gonostylus, hypd= hypandrium, st7= sternite 7, vl =ventral lamella.