Sisyrnodytes oligotrichus, Londt, 2009

Londt, Jason G. H., 2009, A review of Afrotropical Sisyrnodytes Loew, 1856 (Diptera: Asilidae: Stenopogoninae), African Invertebrates 50 (1), pp. 137-137 : 165-166

Sisyrnodytes oligotrichus sp. n.

Figs 31, 32 , 43

Etymology: From Greek oligos (few) and thrix (hair). Refers to the small number of apical scutellar setae.

Redescription:

Male (based on holotype in excellent condition; slightly greasy).

Head: Dark red-brown to black with mainly white setae, but some pale yellow and dark red-brown setae present.Antennae: Dark red-brown except for tip of style which is pale yellowish. Scape and pedicel mostly white setose, major setae pale yellowish. Major ventral setae of pedicel project beyond level achieved by postpedicel. Basal element of style short (shorter than broad). Eye to face width ratio 1.7:1. Mystax shortish, mostly white (dorsally) and yellowish (ventrally), but a few dark red-brown setae laterally on epistomal margin. Frons and vertex mainly white setose except for some yellowish setae on either side of ocellar tubercle. Laterally situated frontal setae not extending below antennal sockets. Occipital setae white, more robust postoculars yellowish. Palps dark red-brown and yellowish setose, proboscis white setose.

Thorax: Dark red-brown to black. Prothorax yellow and white setose. Mesonotum entirely setose except for paramedial strips, sutural and postsutural spots. Lateral macrosetae yellowish; other setae mixed white and yellowish. Scutellum apruinose with poorly defined transverse groove; disc asetose, 6 yellowish and white apical setae. Pleural setae mostly yellowish except for white setae dorsally on anepisternum. Katepimeron yellowish setose, katatergals yellowish, long, shafts more or less smooth. Legs: Dark red-brown, mainly white setose, major setae yellowish, blackish setae distally on tibiae and ventrally on tarsi. Claws longish, dark red-brown; empodia short yellowish; pulvilli minute to absent. Wings 4.6× 1.9 mm; C white setose basally; membrane transparent except for small pale yellow-brown basal area. Haltere with pale yellow knob, light brown stalk.

Abdomen: Dark red-brown, white setose. Tergal setae well developed laterally and along posterior margins, other setae tiny, transparent (giving anteromedial parts of terga an asetose appearance).

Genitalia ( Figs 31,32 ): Epandrium reduced and simple in structure, proctiger extending beyond it. Gonocoxite with shortish external lobe tapering to acute tip, internal lobe fairly robust, with somewhat bilobed distal end. Gonostylus fairly well developed, simple in structure. Hypandrium somewhat flattish with rounded proximal part and long, laterally compressed medial lobe projecting beyond levels reached by gonocoxite and gonostylus. Aedeagus fairly slender with small, tapering, blunt tip.

Female: Similar to male. Variation:Wing length ơ 4.0– 4.6 mm (– x= 4.3 mm, n=2), ^4.5 –5.1 mm (– x= 4.9 mm, n=4). A remarkably uniform species. Individual variation minimal (i.e. intensity of basal wing staining varies, while one female has wing membranes weakly stained adjacent to veins). Holotype: ơ NAMIBIA: ‘ Namibia 24.iv.1983 / 10km E Usakos [22°00'S: 15°35'E] 2115DC / Londt & Stuckenberg / Roadside vegetation’ ( NMSA).

Paratypes: 1 ơ 4^same data as holotype ( NMSA). Note : Paratype ơ terminalia were lost after removal.

Distribution, phenology and biology: Known only from the type locality ( Fig. 43 ) and collected only during April (Table 10).

Similar species: This species is similar to ausensis and brevis .

Figures

Figs 31–38. Sisyrnodytes species, ơ terminalia in lateral and ventral aspects: (31, 32) S. oligotrichus sp. n., holotype; (33, 34) S. subater Oldroyd, 1957, Serowe; (35, 36) S. vestitus Oldroyd, 1974, Gemsbok Pan paratype; (37, 38) S. xeromyia sp. n., holotype. Scale lines = 1 mm.

Fig. 43. Distribution of Sisyrnodytes curtus (Wiedemann, 1819) (•), dasykylon sp. n. (·) and oligotrichus sp. n. (9).