Gonioscelis pickeri, 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 : 77-79

Gonioscelis pickeri sp. n.

Figs 95–97 , 152

Etymology: Named for Dr Michael Picker whose collecting activities in the Western Cape have resulted in significant donations of asilids to the Natal Museum – including the holotype of this species.

Description: Based primarily on holotype ơ (NMSA).

Head:Antennal scape and pedicel orange, postpedicel and style dark red-brown, orange setose. Facial swelling pronounced, mystax mostly white (a few orange or brown setae in dorsal part) asetose between gibbosity and antennal sockets. Frons and vertex thinly gold pruinose. Ocellar tubercle weak silver-gold pruinose with orange-brown oc. Occiput gold pruinose (silver along eye margin), setae orange dorsally and centrally, pale yellowwhite ventrally. Proboscis dark red-brown with white setae, palpus orange-brown, white setose.

Thorax: Dark red-brown, gold pruinose. Postpronotal lobes orange-brown, contrasting somewhat with mesonotum although adjacent parts not greatly different, with a group of strong orange macrosetae. Mesonotal setae: ac weak, black anteriorly; approx. 20 pairs dc, orange (a few orange-brown anterior of transverse suture), clearly extending anterior of transverse suture; 4 orange-brown npl; 4–5 brown-orange sa; 7–8 brownorange pa. Scutellum dark red-brown to black, with 6 brown-orange mrg sct. Wing length 10.8 mm, membrane mostly pale yellow. Legs: Brown-orange, setae orange and yellow. Prothoracic coxa dark red-brown, thinly gold pruinose, yellow and white setose except for dark red-brown setae on spur; femoral spur sharply pointed (angle approx. 25°).

Abdomen: Tergites dark red-brown to black, silver pruinose, fine yellow-white setose. Sternites similar to tergites.

Terminalia ( Figs 95–97 ): Epandrial lobes and proctiger projecting to about same level, lobes tapering distally to slightly downturned tips equipped with fine setae; gcx parallelsided (viewed laterally), distally with two dorsal projections and a ventral broadlyrounded lobe; hyp, in ventral view, slightly broader than long, tapering moderately to mid-length before rapidly tapering to mediodistal finger-like projection bearing long fine setae.

Variation:A very variable species with respect to general coloration. Setae described as being yellow or orange may be black while antennal segments and leg coloration described as orange may be black. This variation is found sympatrically as well as allopatrically. There is, however, reasonable uniformity in male genital morphology. The similarity to haemorhous and hispidus mentioned below suggests that a far more detailed study of these species, based on more material from many more localities, is necessary.

Type material: Confined to specimens from the Biedouw Valley and Kamieskroon area as reliably identifiable male specimens are available from these places: SOUTH AFRICA: 1ơ paratype, ‘ Kamieskroon / SE 3017 Bb / 16-ix-1983 / E de Wet’; 1ơ 2^ paratypes, ‘ Sth Africa Cape Prov / 17km S. Kamieskroon / 3017BD 5.ix.1983 / Londt & Stuckenberg / Slopes with succulent / plants and bushes’; 1ơ 1^ paratypes, ‘ South Africa: W. Cape / 10km e. Kamieskroon / 17-x-1977 3018AA / Ray M. Miller 630m’; 1ơ holotype, 5ơ 6^ paratypes, ‘S. Africa: SW Cap #102 / Biedouw Valley / 32°06'S 19°14'E 350m / 1-12.ii.1991, M. Picker / Succulent Karoo’; 1^ paratype, ‘ Sth Africa: Cape Prov / Biedou Valley 300m / 32°06'00"S: 19°19'00"E / J Londt B Stuckenberg / & P Croeser 6.ix.1989 / Rocky gentle N slope / Scrub & wild flowers’; 1^ paratype, ‘ Biedouw Valley / Namaqualand / 24/9/89 / M Picker / B Leon’ .

Type locality: South Africa: Western Cape Province, Biedouw Valley .

Other material: SOUTH AFRICA: 2ơ 4^, ‘Namaqual. / O’okiep. [29°36'S 17°52'E]’ ~ ‘Lightfoot / Sep. 90’ (SAMC); 1^, ‘Springbok [29°40'S 17°53'E] / 20-21.ix.1970 / Potgieter & Snyman’; 1ơ 1^, ‘ Cape Province / Namaqualand / Mesklip / 29°48'S, 17°52'E / 1.x.1985 / F.W. & S.K. Gess’ (AMGS); 1^, ‘South Africa, Cape Prov. / 13.5 mi. SSW Springbok / nr Neweputs Farm, 2600 ft / Sept. 7, 1972, ME & BJ Irwin / 2917Dd’; 1^, ‘R.S.A.: N Cape #82 / Goegap Nature Reserve / 29°40'S 18°00'E 870m / Date: 23.viii.1995 / Coll: J. & A. Londt / Flowers Dry stream bed’; 1^, ‘Sth Africa: Cape Prov / 78 km S of Springbok / 30°01'30"S: 17°52'30"E / 31.viii.1989 700m / B Stuckenberg J Londt / P Croeser Sandy area / 4km S Bufelsrivier’; 2ơ, ‘ Cape Province / Namaqualand / Sors Sors / 30.08S 18.01E / 30.ix.1995 / F.W., S.K. & R.W. Gess’, ‘shaken from / Rhenosterbos’ (AMGS); 1ơ, ‘ Cape Province / Namaqualand, Kamies- / berg, Bakleikraal / 30.13S 18.03E / 28.ix.1995 / F.W., S.K. & R.W. Gess’ (AMGS); 1^, ‘ Cape Province / Namaqualand, Kamies- / berg, Bakleikraal / 30.13S 18.03E / 28.ix.1995 / F.W., S.K. & R.W. Gess’ [ Coleoptera : Scarabaeidae ] (AMGS); 1ơ, ‘S. Afr. CP / Karagams E / 3018Ac / 23.8.1985 / V B Whitehead / M Macpherson’ (SAMC); 1^, ‘Klaver [31°47'S 18°37'E] C.C. / 19.9.1917 / A. Roberts’; 1^, ‘ Cape Province / Nieuwoudtville / Skuinshoogte Pass / 31.16S 19.08E / 23-30.ix.1994 / F.W. & S.K. Gess’ (AMGS); 1ơ, ‘ 5m. N. of / Nieuwoudt- / ville [31°22'S 19°06'E]’ ~ ‘S.A.M. / 9:1961’ (SAMC); 1^, ‘ Cape Province / 10km E of Nieuwoudt- / ville [31°22'E: 19°06'E] on road to / Calvinia, 4.x.1989 / F.W. & S.K. Gess’ (AMGS); 1ơ, ‘South Africa, W. Cape Prov. / 54 km NE Clanwilliam, base of / Botterkloof Pass; 12-ix-1996 / K. C. Holston; 490m. / 31°50'22"S. 19°16'01"E’, ‘Schlinger Foundation South / Africa & Namibia Expedition / Oct.-Dec. 1996 ’, ‘INHS / Insect Collection / 33,508’ (INHS); 3ơ 1^, ‘Graafwater [32°09'S 18°36'E] / C.P.’ ~ ‘Mus., Exp., / Oct., 1947.’ (SAMC); 2ơ, ‘Ysterfontein [=Yzerfontein 32°11'S 18°46'E]’ ~ ‘S.A.M. / 9:60’ (SAMC); 3^, ‘ Cape Province / Clanwilliam [32°11'S 18°54'E] District / Klein Alexandershoek / 32°20'20"S, 18°46'E / 28.ix.1985 / F.W. and S.K. Gess’ (AMGS); 4ơ, ‘ 4 m. S. of / Clanwilliam [32°11'S 18°54'E] / C.P.’ ~ ‘S.A.M. / 9:1961’ (SAMC).

Notes: G. pickeri and scapularis are sympatric at 4 m. S. of Clanwilliam.As scapularis dominates the SAMC samples, and females are not readily separable, all females are listed under scapularis .

Distribution, phenology and biology (Tables 1–2, Fig. 152): Confined to the western parts of South Africa (Northern Cape and Western Cape provinces) between Springbok and the Clanwilliam area. This area lies entirely within the Succulent Karoo biome. It is interesting that a gap appears to exist between two concentrated groups of records. The gap corresponds with a poorly accessed area, centred on Bitterfontein and Nuwerus, renowned for being particularly arid and going by the Afrikaans name Knersvlakte. The absence of material from this area probably reflects inadequate sampling. Most of the material has been collected between August and October, but a good series collected in February suggests a much longer period of adult activity. There are six Natal Museum prey records as follows: 1ơ 5^ (78 km S Springbok 1; Biedouw Valley 5) – Coleoptera ( Scarabaeidae 4), Diptera ( Asilidae 1 – G. maculiventris ), Hemiptera ( Alydidae 1).

Similar species:A species closely related to ceresae , haemorhous , hispidus and scapularis in that males possess a single distomedial hypandrial projection. The hypandrium is, however, somewhat longer, and somewhat upturned when compared with the other species. Like hispidus the epandrial lobes taper gently toward their apices in lateral view. It is possible that all these species are no more than geographical variants of one species, but more information is required before this can be ascertained. G. melas also has males with a single distomedial hypandrial process, but is otherwise different and perhaps more closely related to punctipennis and its allies (see comment under melas ).

Figures

Figs 89–100. Gonioscelis male genitalia. 89–91. G. nigripennis Ricardo, 1925 (Erikson’s Drift syntype), left epandrial lobe fractured. 89. Lateral. 90. Dorsal. 91. Ventral. 92–94. G. phacopterus Schiner, 1867 (Clifton). 92. Lateral. 93. Dorsal. 94. Ventral. 95–97. G. pickeri sp. n. (Biedouw valley paratype). 95. Lateral. 96. Dorsal. 97. Ventral. 98–100. G. pruinosus Ricardo, 1925 (Narok syntype). 98. Lateral. 99. Dorsal. 100. Ventral. Scale lines = 1 mm.