Ommatius (Pygodactalyus) fluvius, Scarbrough & Marascia, 2003

Scarbrough, Aubrey G. & Marascia, Claudio G., 2003, Revision of Ommatius Wiedemann (Diptera: Asilidae). IV. Pygommatius subgen. nov. with twenty-five Afrotropical species, Zootaxa 228 (1), pp. 1-94 : 34-35

Ommatius (Pygodactalyus) fluvius , sp. n.

Figs. 9 , 40 , 126­133

Male. As O. comosus except as follows. Length, body 11.7 mm; wing 7.5 mm. Head: FHWR 1.0:11.4. Palpus entirely brown. Scape and pedicel brown­yellow dorsally and medially, yellow elsewhere.

Thorax: Scutellum brown; scattered yellow setae. Pleuron yellow with narrow black triangle extending across anepisternum and katepitergite, triangle widest dorsally.

Wing ( Fig. 9 ): Narrow apex and posterior margin dense microtrichose. Cell r 4 with R 5 slightly convex medially. Apex of cell m 3 perpendicular to axis of wing, near r­m.

Leg: Hind trochanter brown­yellow posteriorly and dorsally, yellow anteriorly; 1 short, peg­like bristle present. Fore and middle femora yellow, apex anteriorly and dorsally brown­yellow. Fore femur (see O. brevicornis , Fig. 23 ) with a ventral row of 7­8 unusually thick, yellow bristles. Middle femur ventrally with only long, thin, yellow setae. Hind femur (see O. comosus , Fig. 31 ); HFWLR 1.0:5.7. Hind tibia ( Fig. 40 ) slightly calf­like, apex and middle wider than base; anterior, preapical constriction and abundant, erect, brown setae present on basal half.

Abdomen: Mostly brown to yellow brown, with thin brown tomentum and brown setae; wide lateral margins of tergites 1­4 yellow with yellow tomentum with yellow setae; tergite 4 with a thin fringe of 7­8 yellow bristles on apical half of lateral margin; apical margin of tergites 6­8 with apical margin produced medially. Sternites 1­3 yellow, sternite 4 yellowish­brown medially; sternites 4 and 5 with 2 admedial stripes of erect, brown setae, those on sternite 4 short with nearly parallel sides, pencil­like, those on 5 longer with pointed apices; sternite 6 brown setose with 2­3 erect, admedial setae on basal half, setae otherwise shorter and decumbent. Sternite 8 with brown bristles along apical margin.

Terminalia ( Figs. 126­130 ): Ventral lamellae with raised median carnia. Epandrium with only 2 obvious branches, dorsal branch wide, dorsal apical corner pointed; ventral branch narrower, slightly longer than dorsal branch, apex asymmertically bifid with stout bristles. Gonocoxite with minute setae in large sockets.

Female. Differs from male as follows. Length, body 12.2 mm; wing 9.5 mm. Head: Face ventrally with thick brown or yellow bristles; FHWR 1.0:10.6. Pedicel and scape brown. Occiput with brown postocular bristles extending to midlateral margin of eye. Thorax: Pleuron with meron partly brown. Leg: Brown color darker than in male. Unusual vestiture of legs and calf­like shape of hind tibia absent. Fore and middle femora brown on apical third anteriorly and apical half dorsally; middle femur with yellow and brown posteroventral setae. Hind femur brown on apical half, extending dorsally and ventrally to or near base; 2 well defined ventral rows of 4­5 long, thin, brown bristles; abundant, short, bristles present posteriorly; thin ventral and posterior setae absent; HFWLR 1.0:5.7. Fore and middle tibiae with narrow apex brown; all bristles tibiae and tarsi brown. Abdomen: Tergites with long, thin brown bristles along apical margin; unusual vestiture of male absent. Tergite 9 about as long as cercus. Terminalia ( Figs. 131­133 ): Three spermathecae present, narrow with sides gradually tapered to apex; duct basal, slightly lateral in position. Apical margin of sternite 8 triangular, sides oblique with a prominent notch laterally; cuticle medially thin with a deep narrow groove extending to apical margin; apical corner with 3­4 thick bristles.

SPECIMENS EXAMINED. Holotype ♂, allotype ♀, GABON: Museum Paris / Congo Ogoové / Sam Kita / R . Ellenberger 1910, ( MNHN). Paratype: GABON: 1 ♀, Museum Paris / Ogoové / Lambaréné / R . Ellenberger 1911, ( MNHN) .

Distribution. Known only from the type locality in Gabon.

Etymology. Latin fluvius , for ‘of or belonging to a stream or river’, referring to the species being found along the Ogoové River.

Remarks. The male of O. fluvius is easily distinguished from congeners by the unique terminalia ( Figs. 126­133 ), the sparse, yellow, fringe of bristles on the lateroapical half of tergite 4, and the sparse, erect, admedial setae on the basal half of sternite 6. The long tergite 8 and deep lateral notch of sternite 8 ( Fig. 133 ) distinguish the female.

Figures

FIGURES 1­10. Right wing of male Ommatius (Pygommatius) spp. 1. O. alatipes, sp. n..; 2. O. albatus Martin; 3. O. bingeri Oldroyd; 4. O. brevicornis Curran; 5. O. cingulatus Bromley; 6. O. comosus, sp. n..; 7. O. dasypogon Oldroyd; 8. O. digittatus Oldroyd; 9. O. fluvius sp. n..; 10. O. grossus, sp. n. Abbr. R4 =fourth radial vein, r4 = fourth radial cell, m1= first medial cell, m3=third medial cell, d = discal cell, r­m = radial­medial crossvein.

FIGURES 39­48. Left hind tibia of male Ommatius (Pygommatius) spp. 39. O. comosus, sp. n.; 40. O. fluvius, sp. n.; 41. O. imaginus, sp. n.; 42. O. limbus, sp. n., anterior; 43. O. litoreus, sp. n.; 44. O. neglectus Bromley; 45. O. porticus, sp. n.; 46. O. renudus, sp. n.; 47. O. strigiatus, sp. n.; 48. O. vultus, sp. n., inner surface.

FIGURES 126­133. Male terminalia of Ommatius fluvius, sp. n 126­128. Lateral, dorsal and ventral views; 129. Gonostylus; 130. Aedeagus, lateral view. Female terminalia. 131. Spermatheca; 132. Genital fork; 133. Sternite 8, ventral view.

FIGURES 21­28. Right wing of male Ommatius (Pygommatius) spp. 21. O. talus, sp. n.; 22. O. vultus, sp. n.; 23­28. Right fore femur of male Ommatius (Pygommatius) spp. showing arrangement of anteroventral bristles. 23. O. brevicornis Curran; 24. O. grossus, sp. n.; 25. O. limbus, sp. n.; 26. O. litoreus, sp. n.; 27. O. strigiatus, sp. n..; 28. O. vultus, sp. n.

FIGURES 29­38. Male Ommatius (Pygommatius) spp. 29. O. jaculator Walker, middle femur. 30­ 38. Hind femur, 30. O. brevicornis Curran, anterior view; 31. O. comosus, sp. n., anterior view; 32. O. dasypogon Oldroyd, anterior view; 33. O. jaculator Walker, anterior view; 34. O. limbus, sp. n., with coxa, anterior view; 35. O. litoreus, sp. n., anterior view; 36. O. neglectus Bromley, anterior view; 37. O. strigiatus, sp. n., posterior view; 38. O. vultus, sp. n., posterior view.