Gonioscelis iota, 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 : 54-55

Gonioscelis iota sp. n.

Figs 61–63 , 150

Etymology: Gr. iota – anything very small. Refers to the small size of this species.

Description: Based primarily on holotype ơ (NMSA).

Head: Antenna dark red-brown to black, setae black and white. Facial swelling pronounced, mystax mostly black, a few white setae centrally, confined to gibbosity. Vertex gold-silver pruinose. Ocellar tubercle apruinose with long black oc. Occiput silver pruinose, setae long black proclinate dorsally, pale yellow centrally, fine white ventrally. Proboscis and palpus black, with white setae.

Thorax: Dark red-brown, mesonotum gold-silver pruinose, pleura with silver pruinose and apruinose areas. Postpronotal lobes not contrasting with adjacent mesonotum, with brown, yellow and white setae. Mesonotal setae black: ac not clearly differentiated; approx. 10 pairs dc, extending anterior of transverse suture; 3 npl; 3 sa; approx. 7 pa. Scutellum dark red-brown, with 8 black mrg sct. Wing length 5.4 mm, membrane pale gray (not obviously coloured and lacking distinctive spots). Legs: Coxae, trochanters and femora black (distal tips of femora orange-yellow), tibiae orange with dark redbrown ventral parts, tarsi mostly orange (distal segments brown), setae white except for black setae associated with femoral spur. Prothoracic coxa black, silver pruinose, white setose; femoral spur bluntly pointed (angle approx. 65°).

Abdomen: Tergites black, silver-gold pruinose dorsally and along hind margins (laterally mostly shiny apruinose), setae white. Sternites black, apruinose, white setose.

Terminalia ( Figs 61–63 ): Short ep, proctiger projecting beyond level attained by epandrial lobes, lobes hardly tapering distally, with fine setae distally; gcx with three distal projections, upper two closely associated while third is ventrally situated and seen as a broadly-rounded lobe, a few fine setae are associated with these projections; hyp, in ventral view, clearly broader than long, tapering quickly to a broadly-rounded apex equipped with fine setae.

Variation: A remarkably constant species showing virtually no individual variation. The single available female demonstrates no sexual dimorphism.

Type material: SOUTH AFRICA: 1ơ holotype, 4ơ paratypes, ‘ R.S. A.: N Cape #85 / 5 km N of Komaggas / 29°45'S 17°31'E 390m / Date: 24.viii.1995 / Coll: J. & A. Londt / Rocky slope Macchia’; 4ơ paratypes, ‘ South Africa, Cape Prov / Messelpadpas 25mi SSW / Springbok Sept. 7, 1972 / 1100ft, M.E. Irwin, 2917 Dc / at stream seepage’; 3ơ 1^ paratypes, ‘ Cape Province / Namaqualand / Springbok, Hester / Malan Nature Res. [= Goegap Nature Reserve 29°40'S 18°00'E] / 15-21.x.1987 / F.W. and S.K. Gess’, ‘at water’ [^ lacks this label] ( AMGS) ; 2ơ 2^ paratypes, ‘ Namaqualand / Bowesdorp [30°09'S 17°56'E] / S.A. Museum’ ~ ‘ Museum Staff / Sept. 1941 ’ ( SAMC) ; 1^ paratype, ‘ Swart Doring R. [= Swart Doringrivier 30°47'S 17°51'E] / Namaqualand’ ~ ‘2- 3.10.1966 / S.A.M. ’ ( SAMC) ; 1ơ 1^ paratypes, ‘ South Africa: W. Cape / 10km e. Kamieskroon / 17-x-1977. 3018AA / Ray M. Miller 630m’; 2ơ paratypes, ‘ Sth Africa Cape Prov / Studers Pass 22km NE / of Garies 3018AC / 6.ix.1983 J Londt & / B Stuckenberg Stream / edge & rocky slopes’ .

Type locality: South Africa: Northern Cape Province, 5 km N of Komaggas.

Distribution, phenology and biology (Tables 1–2, Fig. 150 ): Known from a number of Northern Cape localities within an area of Succulent Karoo. Specimens have been captured during August, September and October, when the entire region is known for its abundant wild flowers.The species rests on boulders in areas of indigenous vegetation. There is one Natal Museum prey record as follows: 1ơ (Studers Pass) – Diptera (Rhagionidae) .

Similar species: A small species clearly related to punctipennis and its allies ( chloris , exouros and kedros ). It occurs in similar environments and sympatrically with punctipennis . The wings lack the distictive spotting of the punctipennis group, while the hypandrium is relatively short and not bilobed mediodistally. Other species with which iota should be compared are xanthochaites and melas .

Figures

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 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.