Gonioscelis xanthochaites, Londt, 2004

Londt, Jason G. H., 2004, A review of the afrotropical genus Gonioscelis Schiner, 1866 (Diptera: Asilidae), with descriptions of new species, African Invertebrates 45, pp. 21-124 : 100-101

Gonioscelis xanthochaites sp. n.

Figs 16 , 137–139 , 147

Etymology: Gr. xanthos – yellow + chaite – long hair, mane. Refers to the long yellow mesonotal setae possessed by this species.

Description: Based primarily on holotype ơ (NMSA).

Head: Antennal scape brown-orange, pedicel brown, postpedicel dark red-brown, setae yellow. Facial swelling pronounced, mystax confined to gibbosity, mostly black (a few white setae in ventral half). Vertex weakly gold pruinose. Ocellar tubercle largely apruinose with black oc. Occiput silver pruinose, setae yellow (somewhat paler and wavy ventrally). Proboscis and palpus dark red-brown to black, pale yellow setose.

Thorax: Dark red-brown to black, silver-gold pruinose. Postpronotal lobes orange, contrasting with adjacent mesonotum, with many long yellow setae. Mesonotal setae mostly yellow (mixed with finer setae and difficult to count): ac weakly differentiated, dark brown;>10 pairs dc, clearly extending anterior of transverse suture, yellow postsuture, black anterior of suture; 4–5 npl; approx. 6 sa; approx. 6 pa. Scutellum dark red-brown, with approx. 8 yellow mrg sct. Wing length 8.2 mm, membrane stained light brown, with paler areas. Legs: All trochanters black, prothoracic femur orange with black base and spur, tibia and tarsus orange, setae yellow except for those on spur and a few on tarsus; mesothoracic femur, tibia and tarsus orange, all setae yellow except for a few on tarsus; metathoracic femur orange, narrowly black dorsobasally and dorsodistally, tibia orange with dark red-brown distal half, tarsus dark red-brown, setae yellow except for a few on tarsus. Prothoracic coxa black, silver pruinose, yellow setose; femoral spur ( Fig. 16 ) sharply pointed (angle approx. 25°).

Abdomen: Tergites dark red-brown to black, thinly silver pruinose dorsally and along hind margins, rest shiny apruinose, setae long yellow wavy. Sternites dark red-brown, apruinose, setae long yellow wavy.

Terminalia ( Figs 137–139 ): Short ep (proctiger projecting beyond level attained by epandrial lobes), lobes tapering distally to somewhat truncate setose apices; gcx with three distal projections and a small group of macrosetae; hyp, in ventral view, clearly broader than long, tapering rapidly to slightly widened almost trilobed truncate apex, lobes equipped with a number of macrosetae.

Variation: The two available specimens agree well with each other. Female unknown.

Type material: NAMIBIA: 1ơ holotype, 1ơ paratype, ‘Namibia Outskirts of / Aus overlooking town / 2616CA 30.viii.1983 / Stuckenberg & Londt / Rocky area / Shrubs’ .

Type locality: Namibia: Outskirts of the small town of Aus .

Distribution, phenology and biology (Tables 1–2, Fig. 147 ): Known only from the type locality in southern Namibia. The area receives winter rainfall and specimens were collected resting on boulders in August.

Similar species: A distinctive species that appears most closely similar to punctipennis and its allies. The wings lack the spotted appearance of punctipennis , but possess interesting shading unlike any other species in the ‘complex’ associated with punctipennis ( chloris , exouros , iota , kedros and possibly melas ).

Figures

Figs 10–17. Gonioscelis species, left prothoracic femur, showing variation in spur development and method of measuring spur angle (16–17). 10. G. melas sp. n. (25 km N Kamieskroon). 11. G. chloris sp.n. (4 km SW Clanwilliam). 12. G. longulus Ricardo, 1925 (Paul Roux). 13. G. cuthbertsoni sp. n 7 km SE Angwa Bridge). 14. G. macquartii Jaennicke, 1867 (Nguruma). 15. G. nigripennis Ricardo, 1925 (Erikson’s Drift). 16. G. xanthochaites sp. n. (Aus). 17. G. hadrocantha sp. n. (Roçadas). Scale lines = 1 mm.

Figs 134–142. Gonioscelis male genitalia. 134–136. G. whittingtoni sp. n. (Madzidzi Bay paratype). 134. Lateral. 135. Dorsal. 136. Ventral. 137–139. G. xanthochaites sp. n. (Aus paratype). 137. Lateral. 138. Dorsal. 139. Ventral. 140–142. G. zulu sp. n. (Mhlopeni Nature Reserve paratype). 140. Lateral. 141. Dorsal. 142. Ventral. Scale lines = 1 mm.

Figs 146–147. Distribution of Gonioscelis species found only in southern Africa. 146. closed circle = bykanistes, open circle = cuthbertsoni, closed square = hadrocantha, open square = mantis. 147. closed circle = engeli, open circle = scapularis, closed square = ventralis, open square = xanthochaites.