Ommatius prolixus, Scarbrough, 2010

Scarbrough, A. G., 2010, An overview of the Afrotropical Ommatiinae (Diptera: Asilidae) with a key to genera, Zootaxa 2540, pp. 1-47 : 33-35

Ommatius prolixus , n. sp.

Figs. 83–88

Description, male. Body 11.3 mm; wing 8.3 mm. Head: Face gray tomentose with scattered vestiture; mystax pale yellow, sparse setae, 4–5 pencil-like bristles plus 9 longer, thinner, brown bristles; FHWR 1.0:7.5. Palpus, proboscis, and frons yellowish or whitish setose. Antenna brownish, scape entirely and base of pedicel brownish-yellow; brown setose; flagellum slightly shorter than scape and pedicel together; FWLR 1.0:1.9. Frons yellowish tomentose. Ocellar tubercle brown setose, 2 setae slightly shorter than scape and pedicel combined. Occiput yellowish tomentose with yellowish and white setae; postocular bristles mostly yellow, 1– 3 dorsal bristles brown, apex of longest about 1/3 distance beyond eye margin.

Thorax: Pronotum brownish-gray or gray tomentose with whitish or yellowish vestiture. Mesonotum brown, postalar callus brownish-yellow, tomentum dense, yellowish or grayish; brown as follows: wide brown median stripe and 2 spots laterally, streak divided longitudinally and spots separated by yellowish tomentum narrowly; sparse brown setae medially, whitish setae laterally; 3 dorsocentral and 5–8 lateral bristles black. Scutellum gray tomentose with scattered white setae and 2 long black marginal bristles. Pleuron yellowish-gray or gray tomentose, vestiture pale yellow or white; anepimeral bristles thin, seta-like; ground color of metacoxa and metepisternum yellow. Halter yellow. Wing ( Fig. 83): Hyaline; apical 1/3 and narrow posterior margin with dense microtrichia, sparse or absent otherwise. Cell r 4 narrowly triangular, slightly sigmoid apically, base well beyond apex of cell d. Crossvein r-m beyond middle of cell d, about as long as CuA 1 +M 3. Cell m 1 wide, narrow base, vein M 1 strongly arched anteriorly; m 1 WR 1.0:2.6:2.5. Legs: Coxae yellowish tomentose with pale yellow or whitish vestiture; coxae yellow, meso- and metathoracic coxae brownish-yellow anteriorly. Trochanters yellow, apical margin blackish; metathoracic trochanter with whitish bristles. Femora slender; anterior bristles mostly brown. Pro- and mesothoracic femora yellow, slightly brownish-yellow anteriorly; prothoracic femur posteriorly and ventrally with abundant, long, wavy, yellowish setae, including a ventral row, sparse brown setae posterodorsally; basal 1/3 of prothoracic femur with 2–3 bristles posteriorly. Mesothoracic femur with thin bristles ventrally, those posteroventrally slightly thicker; sparse long, thin, wavy setae posteriorly; preapical posterodorsal bristle brown. Metathoracic femur mostly brown anteriorly and dorsally, apical 1/2 ventrally and posteriorly brown, yellow or brownish-yellow elsewhere; MFWLR 1.0:6.9. Pro- and mesothoracic tibiae yellow with mostly yellow vestiture; prothoracic tibia with a fringe of abundant, yellowish setae and long, thin, yellow bristles laterally, setae not unusually dense. Metathoracic tibia with apical 1/4 brown, and only brown bristles. Tarsi with basal tarsomeres yellow, narrow apices brown; apical 4 tarsomeres brown with narrow yellow bases, bristles brown; basal tarsomere of prothoracic tarsus with 2 yellow bristles and thin fringe of yellow setae.

Abdomen: Dark brown with narrow apical margins of segments yellow; mostly yellowish-gray tomentose, white setose; tomentum becoming slightly brownish-yellow and thin on apical 3–4 segments, apical 1–2 tergites sunshiny; apical 4–5 tergites dorsally and sternites 7–8 with numerous brown setae, brown setae sparse on preceding segments; apical margin of tergites 1–6 with a row of yellow setae, 2–3 in apical corners longest and thickest. Terminalia ( Figs. 84–88): Dark brown, wider than abdominal segment 8, as long as combined length of segments 7–8. Epandrium wide in lateral view curved or slightly angled posteriorly, apices contrastingly narrow and short, somewhat truncate in dorsal view. Gonostylus subrectangular, wide basally, narrow and hooked apically; concave laterally. Gonocoxite fused with hypandrium basally, inner margin elongate with 1–2 yellow setae apically. Hypandrium with apical margin broadly rounded, slightly angled preapically, with narrow U-shaped band of dense, brown setae.

Female. Unknown.

Type. MALAWI: Zomba Plateau [1523ʹS 3520ʹE _] / 24–27.xi.1980 1500 m, / Stuckenberg & Londt / 1535 Ad montane forest (holotype ♂, NMSA) .

Etymology. Latin prolixus , for broad or wide, referring to the diameter of the epandrium in lateral view.

Distribution.Collected in November in a montane forest on the Zomba Plateau, Malawi.

Remarks. The sparse vestiture of the lower face, fringe of setae on the prothoracic leg, and characters of the terminalia ( Figs. 84–88) distinguishes the male of O. prolixus from congeners. The male is further distinguished by the wide epandrium in lateral view and blunt apex, broadly rounded hypandrium, and shape of the gonostylus.