Gonioscelis chloris, 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 : 38-39

Gonioscelis chloris sp. n.

Figs 11 , 30–32 , 151

Etymology: Gr. Chloris – Goddess of flowers. Refers to the type-locality of Clanwilliam, a centre renowned for its wild flowers.

Description: Based primarily on holotype ơ (NMSA).

Head: Antenna dark red-brown, pedicel brown distally, setae pale yellow and white. Facial swelling pronounced, mystax confined to gibbosity, mostly black with a few white or pale yellow ones along epistomal margin. Frons and vertex black, weakly redgold pruinose. Ocellar tubercle apruinose with black oc. Occiput black, silver pruinose except for extensive apruinose area behind vertex, setae short dark-brown dorsally, white centrally and ventrally. Proboscis and palpus dark red-brown, fine white setose.

Thorax: Dark red-brown (mesonotum) to black (pleura), silver (pleura) or red-gold (mesonotum) pruinose. Postpronotal lobes red-brown, not contrasting with immediately adjacent mesonotum, with approx. 10 white setae. Mesonotal macrosetae black: a approx. 7 pairs; approx. 15 pairs dc extending along entire length of mesonotum; 3 dark redbrown to black npl; approx. 4–5 sa; 3 pa. Scutellum dark red-brown to black, with 4 black mrg sct. Wing length 5.2 mm, membrane mostly pale brown-yellow with dark brown spots at major forks. Legs: Femora black with orange-brown distal ends, tibiae orange-brown (slightly darker distally), tarsi dark brown, setae mostly white (black ones on prothoracic spur and ventrally on tarsi). Prothoracic coxa black, apruinose except for distal part which is silver pruinose, white setose; femoral spur ( Fig. 11 ) sharply pointed (angle approx. 20°).

Abdomen: Tergites black, silver pruinose hind margins, setae sparse white. Sternites blackish, apruinose, fine white setose.

Terminalia ( Figs 30–32 ): Moderately short ep (proctiger projecting slightly beyond epandrial lobes), tapering slightly distally in lateral aspect, with minor setae distally; gcx with two projections and a few fine setae distally; hyp, in ventral view, broader than long, tapering slightly to two widely-separated lobes (allowing clear view of aedeagus).

Variation: A uniform species. The single known female is somewhat bigger than the males (wing length approx. 7.2 mm) indicating that there may be some sexual dimorphism relating to size. A larger sample will however be required to verify this.

Type material: SOUTH AFRICA: 1ơ holotype, 1ơ 1^ paratypes, ‘ Sth Africa: Cape Prov / 4km SW Clanwilliam / 32°11'30"S: 18°52'20"E / 28.viii.1989 225m / J Londt B Stuckenberg / & P Croeser Sandy E / slope macchia nr dam’; 1ơ paratype, ‘ Sth Africa Cape Prov / 30km S Clanwilliam / 3218BD 31.viii.1981 / J. Londt, L. Schoeman / and B. Stuckenberg. / Karroid broken veld’ .

Type locality: South Africa: Western Cape, 4 km SW Clanwilliam.

Distribution, phenology and biology (Tables 1–2, Fig.151 ): Restricted to the Fynbos biome in the area west and south of Clanwilliam (i.e. western side of Cedarberg mountains). All four known specimens were collected in August. The species lives in a winter-rainfall area well-known for insect activity at that time of year, before what is often a hot and dry summer. The specimens were collected in an area with sandy soil supporting a vigorous growth of macchia/fynbos vegetation. The specimens were resting on large boulders.

Similar species: Closely related to other spotted-winged species from the southwestern parts of South Africa (i.e. exouros , kedros , punctipennis ). The species was found at a similar time of year and only a few kilometres from the only known localities for kedros which are on the eastern slopes of the Cedarberg mountains. There are small, but consistent morphological differences between males that currently support the separation of these two species. However, the paucity of material indicates that the status of these two species requires confirmation through further collecting.

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 30–41. Gonioscelis male genitalia. 30–32. G. chloris sp. n. (Clanwilliam paratype). 30. Lateral. 31. Dorsal. 32. Ventral. 33–35. G. congoensis Oldroyd, 1970 (holotype). 33. Lateral. 34. Dorsal. 35. Ventral. 36–38. G. cuthbertsoni sp. n. (Angwa Bridge paratype). 36. Lateral. 37. Dorsal. 38. Ventral. 39–41. G. engeli sp. n. (holotype). 39. Lateral. 40. Dorsal. 41. Ventral. Scale lines = 1 mm.

Figs 150–151. Distribution of Gonioscelis species found only along the west coast of South Africa. 150. closed square = ceresae, cross = iota, open circle = melas. 151. closed circle = chloris, open circle = exouros, closed square = kedros, open square = punctipennis.