Ommatius ultimus, Scarbrough, 2010

Scarbrough, A. G., 2010, An overview of the Afrotropical Ommatiinae (Diptera: Asilidae) with a key to genera, Zootaxa 2540, pp. 1-47 : 35-38

Ommatius ultimus n. sp.

Figs. 89–98

Description, male. Black. Body 11.7–12.0 mm; wing 7.5–8.0 mm. Head: Face white tomentose with white setae; mystax dense, flat, tuft of long setae; sparse white setae dorsally; 6–8 thin black bristles; FHWR 1.0:6.4–1.0:7.1. Palpus and proboscis whitish setose. Antenna and ocellar tubercle black setose; flagellum subequal to combined length of scape or pedicel; FWLR 1.0:1.8–1.0:2.1. Frons gray or yellowish-gray tomentose, brown setose. Ocellar tubercle black setose, 2 setae as long as 3 antennal segments. Occiput gray or yellowish-gray tomentose, white or yellowish setose, sparse black setae sometimes present; 8 brown postocular bristles present, apical 1/2–2/3 of longest bristles proclinate, about 1/3 distance toward ocellar tubercle.

Thorax: Pronotum brownish-yellow tomentose dorsally, gray laterally, vestiture whitish or yellowish. Mesonotum brown, grayish tomentose with wide brown tomentose stripe medially and 2 spots laterally, median stripe divided longitudinally, and lateral stripe transversely by grayish-brown or yellowish-gray tomentum; vestiture mostly brown or blackish, setae sparse anteriorly, more abundant laterally, dorsocentral and acrostichal setae short, about as long as combined length of scape and pedicel; 4 dorsocentral and 6 lateral bristles long and blackish. Scutellum yellowish or brownish-gray tomentose, sparsely yellow setose, with 2 blackish marginal bristles. Pleuron yellowish-gray or gray tomentose with whitish or pale yellow vestiture; anepisternum 2–3 long whitish setae posteriorly; 2–3 blackish katatergal bristles; metacoxa brown. Halter yellowish, knob sooty brown. Wing ( Fig. 89): Pale yellow with weak ripples anteriorly; microtrichia from apex to r–m crossvein and narrowly along posterior margin to anal cell, sparse or absent elsewhere. Cell r 4 sigmoid, base just beyond apex of cell d; R 4 joins costa at wing apex. Crossvein r-m just before middle of cell d, about as long as CuA 1 +M 3. Cell m 1 wide, base narrow, vein M 1 arched basally, m 1 WR 1.0:2.6:2.0–1.0:3.4:2.4. Legs: Coxae dark brown except prothoracic coxa usually yellowish laterally, tomentum grayish, vestiture whitish. Pro- and mesothoracic trochanters yellowish, narrow margin blackish; metathoracic trochanter with 2 whitish bristles. Pro- and mesothoracic femora mostly yellow, apical 1/4 brown plus a long, anterodorsal streak, absent or only very faint on prothoracic femur, dark on mesothoracic femur. Prothoracic femur posteriorly and ventrally with scattered, moderately long, yellowish setae, not especially dense, ventral row with setae unusually long, slightly wavy apically. Mesothoracic femur with 3 brown bristles anteriorly; anteroventral setae or thin bristles mostly yellow or brown; usual anterodorsal bristle absent; 4–5 very long, posteroventral and 1 preapical, posterodorsal, yellow bristle present. Metathoracic femur mostly brown, narrow base and large, preapical spot, yellowish; 2 anterior bristles and 4–5 long, wide spaced, brown or whitish; MFWLR 1.0:6.2–1.0.6.3. Tibiae mostly yellow with sparse whitish bristles; narrow apex of pro- and mesothoracic tibiae and apical 1/4 of metathoracic tibia brown; prothoracic tibiae laterally with dense fringe of long white setae and 4–5 long thin bristles. Tarsi mostly brown with brown bristles; basal tarsomere of pro- and mesothoracic tarsi yellow, narrow apices brown; basal tarsomere of metathoracic tarsus brown or brownishyellow; lateral fringe of basal 2–3 tarsomeres of prothoracic tarsus with abundant white setae laterally and 3 whitish bristles; meso- and metathoracic tarsi sometimes with 1 whitish bristle.

Abdomen: Blackish with apical margin whitish, and grayish tomentum, tomentum becoming thin dorsally, apical 2 tergites sparsely tomentose, surface sunshiny; vestiture of narrow lateral margin of tergites 1–5 and sternites 1–5 whitish, vestiture beyond blackish; tergites with apical row of long, thick bristles; sternites 6 and 7 laterally with several, scattered, short, black seta-like bristles, sternite 8 with longer, thinner setae. Terminalia ( Figs. 90–94): Blackish, slightly longer than combined length of segments 7–8, and as wide as segment 8. Epandrium unusually narrow apically, angular in dorsal view. Hypandrium uniformly curved apically; abundant, long, thin, blackish setae present, longer setae curved apically.

Female. Body 12.3–13.0 mm; wing 8.0–10.0 mm; FHWR 1.0:6.9–1.0:7.1; FWLR 1.0:2.1–2.3; m 1 WR 1.0:3.0:2.3–1.0:3.3:3.0; MFWLR 1.0:6.0–1.0:6.2. Head: Face with sparse, pale yellowish vestiture below, mostly black setae and bristles. Ten or 12 black, postocular bristles present. Thorax: Mesonotum with 4–5 dorsocentral bristles; setae mostly brown including that on dorsal 1/2 of postpronotum. Scutellum brownishyellow tomentose, with mostly yellowish setae, scattered brown setae present. Pleuron with anepimeral and most katatergal bristles brown. Wing: Crossvein r-m at middle of d cell. Legs: Prothoracic coxa brownishyellow. Prothoracic leg with lateral fringe of short setae poorly defined; setae more sparse than in male. Pro- and mesothoracic femora without brown anterodorsal streak. Mesothoracic femur with 4–5 anteroventral bristles, slightly thicker than in male. Metathoracic femur with basal 1/4 ventrally and dorsally yellow; 5 anteroventral bristles present, much longer than in male, 4 brown with shortest basal bristle yellow; posteroventral row of bristles extend to apical 1/3, slightly thinner than those in anteroventral row. Metathoracic tarsus with basal tarsomere yellow, narrow apex brown; all tarsi with only brown bristles. Abdomen: Sternites 7–8 laterally with several blackish bristles. Terminalia ( Figs. 95–98): Sternite 8 smooth, apical margin with shallow notch. Genital fork U-shaped, base wide, apical margin broadly notched medially. Spermatheca wide only slightly tapered apically; valves slightly longer than wide.

Types. MALAWI: Senga Hills [13 o 43’S 34 o 35’E] / 1–2.xii.1980 1334DA / ca. 500 m Stuckenberg / & Londt, Brachystegia / woodland near Lake (holotype ♂, NMSA) . Paratypes, MALAWI: Zomba [15 o 23’S 35 o 18’E] / 1535 Ad, 24–27.xi.1980 1100 m / Londt & Stuckenberg / taken at light (1 ♂, NMSA) ; MALAWI: SE1435AC / 25 km n. of Mangoche / 1 km S Club Makokola [14 o 19’S 35 o 08’E] / 11.iii.1987 J. Londt / Grass & thick bush (1 ♂, NMSA) ; same data as holotype (1 ♀, NMSA) ; Mulanje Mnt [Mountain, 15 o 30’S 35 o 31’E] / Likabula River Valley / 28–30.xi.1980 1535 Dc /, 1000 m Stuckenberg & / Londt, Riverine Brachystegia woodland (1 ♂, 1 ♀, NMSA) ; Mulanje [16 o 01’S 35 o 29’E] / Nyasaland, 11–12.1912 / S.A. Neave (1 ♂, BMNH) ; same location, [no dates] J. B. Davey, (1 ♂, 2 ♀, BMNH) .

Other material examined. MALAWI: same data as holotype (1 ♂, 3 ♀, NMSA); Mulanje Mnt [Mountain, 15 o 30’S 35 o 31’E], Likabula river valley, 28–30.xi.1980 1535 Dc , 1000 m Stuckenberg &, Londt, Riverine Brachystegia woodland (7 ♂, 4 ♀, NMSA) .

Etymology. Latin ultimus , referring to the lateral fringe of setae on the prothoracic tibia and basal tarsomeres of the male.

Distribution. Collected in riverine Brachystegia woodlands, grass and thick bush during November, December, and March in Malawi. One male collected at a light.

Remarks. Ommatius ultimus differs from congeners by the characters of the terminalia ( Figs. 90–98). Though similar to O. neotenellus , it is distinguished by the long setae of the hypandrium, usually strongly proclinate, dense fringe of the prothoracic tibia and tarsus, and narrow dorsally curved epandrium.