Gonioscelis hadrocantha, 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 : 48-49

Gonioscelis hadrocantha sp. n.

Figs 17 , 52–54 , 146

Etymology: Gr. hadros – well-developed, bulky, stout, strong, great + akantha – thorn, spine. Refers to the femoral spur that is uniquely equipped with a single large terminal macroseta that is accompanied by a few much smaller subapical macrosetae.

Description: Based primarily on holotype ơ (BMNH).

Head: Antenna black, setae dark red-brown to black. Facial swelling poorly developed, mystax pale white-yellow on gibbosity, yellow-brown and shorter setae lie between gibbosity and antennal sockets. Frons and vertex thinly gold pruinose. Ocellar tubercle apruinose with dark red-brown oc. Occiput gold-silver pruinose except for two weakly apruinose areas behind vertex, setae shiny yellow. Proboscis and palpus dark red-brown to black, pale yellow setose.

Thorax: Blackish, mesonotum gold pruinose anteriorly and silver pruinose posteriorly. Postpronotal lobes blackish, not contrasting with adjacent mesonotum, with few long fine yellowish setae. Mesonotal setae pale yellow: ac not evident; approx. 5 pairs dc, just extending anterior of transverse suture; 2 npl; 3 sa; 3 pa. Scutellum black, silver pruinose, with 3 pale yellow mrg sct. Wing length 7.3 mm (paratypes 8.4 mm (ơ), 9.9 mm (^)), membrane mostly brown-yellow. Legs:Yellow except for coxae, trochanters, metathoracic femora (except tip) and anteroproximal part of prothoracic femora that are dark red-brown, setae mostly yellow (a few black ones associated with spur and ventrally on tibiae and tarsi). Spur with single large terminal upwardly-curved stout macroseta ( Fig. 17 ) accompanied by a few much smaller spine-like setae. Prothoracic coxa black, silver pruinose, white setose; femoral spur moderately pointed (angle approx. 55°).

Abdomen: Tergites black, silver pruinose, setae short yellow. Sternites similar but with narrow medial apruinose strip.

Terminalia ( Figs 52–54 ): Lobes of ep projecting to about same level attained by tip of proctiger, each lobe tapering gradually distally to about two-thirds its length before expanding slightly before somewhat truncate tip, each with a single large macroseta accompanied by smaller macrosetae and setae distally; gcx somewhat attenuate, with three distal projections (one very small) and a group of fine setae; hyp, in ventral view, longer than broad, tapering gradually distally to bilobed apex, lobes equipped with fine setae.

Variation: Little variation evident. The holotype is slightly smaller than the paratypes.

Type material: ANGOLA: 1ơ holotype, 1ơ 1^ paratypes, ‘ Angola (A42) / Roçadas [16°43'S 15°01'E] / 30.iii.1972 ’, ‘Southern / African Exp. / B.M. 1972-1’ ( BMNH) .

Type locality: Angola: Roçadas .

Distribution and phenology (Tables 1–2, Fig. 146 ): Known only from the type locality situated within the Savanna biome, where material was collected in March.

Similar species:A member of the large and widely distributed group of species possessing a poorly defined facial gibbosity.Although linked with other species possessing elongate hypandria (see key), the species has obvious similarities to ventralis in that the hypandrium, although much longer, has similarly shaped terminal lobes, and the epandrial lobes have similarly downturned apices. In other respects, however, these species are easily separable. G. hadrocantha is unique in having the prothoracic femoral spur tipped with a single large macroseta.

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 52–63. Gonioscelis male genitalia. 52–54. G. hadrocantha sp. n. (holotype). 52. Lateral. 53. Dorsal. 54. Ventral. 55–57. G. haemorhous Schiner, 1867 (Stellenbosch). 55. Lateral. 56. Dorsal. 57. Ventral. 58–60. G. hispidus (Wiedemann, 1819) (West Coast National Park). 58. Lateral. 59. Dorsal. 60. Ventral. 61–63. G. iota sp. n. (Komaggas paratype). 61. Lateral. 62. Dorsal. 63. 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.