Gonioscelis phacopterus Schiner, 1867

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 : 76-77

Gonioscelis phacopterus Schiner, 1867

Figs 92–94 , 148

Gonioscelis phacopterus Schiner, 1867: 362 ; Engel 1925: 175.

Redescription: Based primarily on holotype ^ ( NHMW) .

Head: Antenna dark red-brown to black, setae dark red-brown to black. Facial swelling moderately developed, without obvious point at which dorsal region terminates below antennal sockets, mystax uniform pale, shiny brown-yellow, setae between gibbosity and antennal sockets somewhat smaller than those on gibbosity. Frons and vertex silver pruinose. Ocellar tubercle weakly silver pruinose with dark red-brown oc. Occiput silver pruinose, slightly weaker behind vertex, setae short yellow. Proboscis and palpus dark red-brown, pale yellow setose.

Thorax: Dark red-brown to black, mesonotum gold pruinose, pleura silver pruinose. Postpronotal lobes orange, contrasting with adjacent mesonotum, with short yellowbrown setae. Mesonotal setae yellow-brown: ac not evident; approx. 5 pairs dc, not extending anterior of transverse suture; 2–3 npl; 2–3 sa; 2–3 pa. Scutellum dark redbrown, with 4 yellow-brown mrg sct. Wing length 7.7 mm, membrane brown-yellow. Legs: Coxae and trochanters dark red-brown, prothoracic femur, tibia and first tarsomere orange (femur reddish basally on anterior surface), tarsi dark red-brown, mesothoracic legs missing, metathoracic femur and proximal half of tibia orange, femur red-brown dorsally as is distal part of tibia, setae mostly dark red-brown, a few orange. Prothoracic coxa dark red-brown to black, thinly gold pruinose, shiny yellow setose; femoral spur sharply pointed (angle approx. 25°).

Abdomen: Tergites 1–2 dark red-brown to black, T3 similar but with brownish posterior edge, T4 red-brown anteriorly orange-brown distally, T5–8 mostly brown-orange, thinly silver pruinose, setae yellow. Sternites apruinose, S1–2 dark red-brown, rest mostly brown-orange, yellow setose.

Terminalia ( Figs 92–94 ): Epandrial lobes and proctiger projecting to about same level, lobes tapering distally to broadly rounded tips equipped with fine setae; gcx distally with two dorsal projections and two more ventrally situated short macrosetae; hyp, in ventral view, clearly shorter than broad, tapering rapidly to deeply incised bilobed apex bearing a few short macrosetae and fine setae.

Variation: A species showing little individual variation and sexual dimorphism. The association of the Clifton Farm material with the holotype female is done with confidence as these specimens are almost identical in all important ways strongly suggesting that the holotype was collected in the Eastern Cape .

Type material: SOUTH AFRICA: 1^ holotype (seen), ‘ Cap’, ‘ phacopterus / Coll. Winthem’, ‘ Type’ (red) ( NHMW) .

Type locality: Here designated as South Africa: Eastern Cape, Clifton (farm near Grahamstown) .

Other material: SOUTH AFRICA: 2ơ 3^, ‘South Afr: Cape Prov / Clifton Farm 22km NW / Grahamstown 3326AB / 3& 5.i.1986 J&B Londt / & D Gess. Arid area’; 1^, ‘ Cape Province / Clifton [33°11'S 26°24'E] / Grahamstown / 15-i-1981 / D.W. Gess’ (AMGS); 1^, ‘Sammlung / F. Hermann’, ‘ Gonioscelis / phacopterus / Schin.’, ‘Capland / Gonioscelis / phacopterus / ơ [sic.] Schin.’, ‘ phacopterus / Schin.’ (ZSMC).

Notes: Schiner (1867) gives ‘Afrika’ as provenance, but the type is clearly labelled ‘Cap’ thus limiting the distribution to the southern parts of South Africa. The holotype is in fair condition apart from the following: both mesothoracic legs broken off beyond trochanters; terminal four tarsomeres of metathoracic legs and left wing missing; right wing partly torn at mid-length. The ZSMC female, recorded by Engel (1925), may not be correctly identified, but is listed here until verification is possible. Engel’s Hex River specimen (listed twice by him – under phacopterus and maculipennis ) does not agree with the type or the Clifton material, but is similar to hispidus and so is placed under that species.

Distribution, phenology and biology (Tables 1–2, Fig. 148 ): Known with certainty only from one locality in the Eastern Cape province of South Africa where it has been collected in January resting on the ground in scrubby areas of bush and grass. According to Dr Fred Gess (Albany Museum) the area would be classified as ‘Valley Bushveld’, a biome sometimes called ‘Thicket’.

Similar species: A member of the large and widely distributed group of species possessing a poorly defined facial gibbosity. This is a distinctive species whose closest relative probably is lacertosus (see discussion of that species). The hypandrium has similarities to those of mantis and ventralis , but other features clearly separate the species.

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.

Figs 148–149. Distribution of Gonioscelis species found only in southernAfrica. 148. closed circle = genitalis, open circle = longulus, closed square = maculiventris, open square = phacopterus. 149. closed circle = lacertosus, open circle = nigripennis, closed square = ramphis, open square = truncatus.