Longibeccus, Scarbrough, 2010

Scarbrough, A. G., 2010, An overview of the Afrotropical Ommatiinae (Diptera: Asilidae) with a key to genera, Zootaxa 2540, pp. 1-47 : 12

Longibeccus , new genus

Figs. 2, 9, 30 –51,108

Type species: Ommatius fuscovittatus Ricardo, 1900 , by present designation.

Diagnosis. Male. Head: Face moderately produced, gradually sloped or angled forward from antenna to oral margin ( Fig. 9); bristles limited to lower 1/2 of face, only short setae dorsally. Flagellum ( Fig. 3) wider than and as long as scape+pedicel combined; surface sparsely punctuate. Proboscis equal to vertical height of compound eye, slightly compressed medially with vertical height greater than diameter; apex flattened dorsoventrally, awl-shape ( Fig. 9). Anterior scutal setae much shorter than scape. Wing ( Figs. 30, 41): Cell r 1 narrowly pointed; base of cell r 4 at or just before apex of cell d; R 4 slightly concave apically, joining C at or just below wing apex. Leg: Metathoracic femur with short, brown, spur-like, anteroventral bristles, about twice as long as ventral setae. Terminalia ( Figs. 31–36, 42–47): Epandrium deeply excised apically with contrasting shorter dorsal and longer ventral arms, former with several minute denticles along ventral margin. Aedeagal sheath inflated and produced dorsally, forming an epiphallus which extends above and beyond distiphallus in dorsal view. Female ( Figs. 37–40, 48–51). Sparse, unusually stout, bristles on apical margin of abdominal segments 7. Cerci triangular, broad basally, fused medially, without membranous line between cerci; base of cercus extends ventrally, fusing with ventral lamella. Spermathecae oval, slightly longer than wide.

Distribution. Subsaharan Africa.

Etymology. Latin combination Longibeccus . Refers to the long proboscis. Gender masculine.

Remarks. Longibeccus is proposed to accommodate Ommatius fuscovittatus and O. imperator . It is distinguished by the characters in the key and diagnosis, especially the gently sloped face, unusual shape of the flagellum, long proboscis, wing venation ( Figs. 3, 9, 30, 41), and the combined characters of the terminalia ( Figs. 31–40, 42–51). The large plate-like epiphallus concealing the distiphallus dorsally is diagnostic of the genus (35, 36, 46, 47). The epiphallus of Afroestricus ( Fig. 16), Cophinopoda ( Fig. 21), Emphysomera ( Fig. 27) and Thallosia ( Fig. 104) is also dorsal prominent but otherwise structurally different. The cercus which extends onto the ventral surface of the ventral lamella and the oval spermathecal bulbs are distinctive of females ( Figs. 39, 50). In other genera, the cercus covers only the dorsal surface of the pygidium, and the spermathecal bulbs are usually 3 or more times longer than wide and recurved ( Figs. 17, 23, 66, 81, 97). In Michotamia , the spermathecal duct is looped or tightly coiled ( Fig. 55).

Longibeccus is confined to the African Continent with L. fuscovittatus widespread whereas L. imperator are only recorded from equatorial Africa ( Fig. 108).