Gonioscelis engeli, 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 : 42-43

Gonioscelis engeli sp. n.

Figs 39–41 , 147

Gonioscelis setosus: Engel 1925: 171–172 ( Fig. 6 ơ genitalia) not as Wiedemann 1824.

Etymology: Named after Dr E. O. Engel in recognition of his excellent pioneering work on Gonioscelis .

Description: Based primarily on holotype ơ (NMSA).

Head: Antenna dark red-brown to black, setae dark red-brown and dull yellow. Facial swelling moderately developed, without obvious point at which dorsal region terminates below antennal sockets, mystax dull yellow-white, a few small setae on face between gibbosity and antennal sockets. Frons and vertex dull-gold pruinose. Ocellar tubercle gold pruinose with black oc. Occiput mainly gold pruinose, but silver along eye margins, setae dorsally and centrally black (a few yellow-brown), ventrally white. Proboscis and palpus dark red-brown, pale yellow setose.

Thorax: Dark red-brown to black, red-gold and gold-silver pruinose (patterned). Postpronotal lobes brown, contrasting slightly with adjacent mesonotum, with 5–6 black moderately well-developed setae and a few smaller white setae. Mesonotal setae: ac strong black anterior of suture, weaker black postsuture; approx. 30 pairs dc black (a few white posteriorly), extending full length of mesonotum; 3 black npl; 5–6 black sa; 7 white pa. Scutellum dark red-brown to black, gold pruinose, with 4 black mrg sct. Wing length 7.6 mm, membrane dark brownish. Legs: Dark red-brown with areas of orange-brown as follows – prothoracic femur ventrally and anterodistally, prothoracic tibia anteriorly, meso- and metathoracic femora dorsal and ventral stripes, macrosetae mostly dark red-brown (a few white), minor setae white. Prothoracic coxa dark redbrown to black, gold pruinose, white setose; femoral spur moderately pointed (angle approx. 50°).

Abdomen: Tergites dark red-brown to black, thinly gold and silver pruinose except for lateral parts that are shiny black apruinose, setae mostly yellowish. Sternites dark redbrown to black, almost entirely apruinose, white setose.

Terminalia ( Figs 39–41 ): Long ep (lobes projecting beyond tip of proctiger), lobes tapering slightly distally in lateral aspect, each with a large group of well-developed, outwardly-directed macrosetae distally; gcx with three distal projections, the dorsalmost one has a rounded tip while others are closely associated and accompanied by a group of setae; hyp, in ventral view, broader than long, tapering—at first suddenly, and then gradually—to two closely situated terminal lobes, each bearing fine setae.

Variation: A species demonstrating little individual variation or sexual dimorphism.

Type material: SOUTH AFRICA: 2ơ 3^ paratypes, ‘Namaqual. / O’okiep. [29°36'S 17°52'E]’ ~ ‘R Lightfoot / Sep. ‘[18]90’, ‘Sammlung / F. Hermann’ [on 1ơ only], ‘ G. / setosus / Wd. / det. Engel’, ‘ Gonioscelis / setosus Wd. / det E.O. Engel ơ’ (ZSMC); 1^ paratype, ‘O’okiep. / 6/10/[18]96’, ‘Sammlung / F. Hermann’, ‘ Gonioscelis / setosus Wd. ’ ‘Namaqua / Gonioscelis / setosus Wd. ’, ‘ Gonioscelis / setosus Wd. / det E.O. Engel ^’ (ZSMC); 1ơ 3^ paratypes, ‘STH AFRICA: N Cape / 7 km SSE Nababeep / 29°37'13"S: 17°50'29"E / 24.viii.2002 JGH Londt / 1020m Rocky hillside / with sandy areas below’; 1ơ holotype, 2^ paratypes, ‘R.S.A.: N Cape #86 / Skilpad Nature Reserve / 30°10'S 17°47'E 700m / Date: 25.viii.1995 / Coll: J. & A. Londt / Old lands Rocky hill’; 1ơ paratype, ‘ 7m. S. of / Loeries- / fontein [30°58'S 19°27'E] / C.P.’ ~ ‘S.A.M. / 9:1961’ (SAMC); 1ơ 2^ paratypes, ‘Knersvlakte [31°15'S 18°45'E] / Mus. Staff / Oct. 1939 ’ (SAMC); 1ơ 3^ paratypes, ‘Knersvlakte / Namaqualand’ ~ ‘Mus., Expd., / Oct. 1950 ’ (SAMC); 7ơ 8^ paratypes, ‘ 5m. S. of / Van Rhyns / Pass [31°23'S 19°00'E] / C.P.’ ~ ‘S.A.M. / 9:1961’ (SAMC).

Type locality: South Africa: Northern Cape, Namaqua National Park (a new reserve incorporating Skilpad Nature Reserve ) .

Other material: SOUTH AFRICA: 1^, ‘ Knersvlakte’ ~ ‘ 1.10.1966 / S.A.M.’ ( SAMC) .

Taxonomic comments: Engel (1925) misidentified the material he listed under setosus as he had probably not examined the type. The species described and illustrated by him represents a taxon distinct from setosus (now a synonym of hispidus ) and is named here.

Distribution, phenology and biology (Tables 1–2, Fig. 147 ): Known mainly from the Northern Cape province of South Africa, distribution being confined to the northern part of the west coast, an area within the Succulent Karoo biome and receiving winter rainfall. Material has been collected in August, September and October. Specimens were found on open ground in areas with macchia vegetation.

Similar species:A member of the large and widely distributed group of species possessing a poorly defined facial gibbosity, G. engeli occurs in an area dominated by species possessing pronounced gibbosities. The distinctive male genitalia appear most similar to those of mantis .

Figures

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 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.

Figs 6–9. Gonioscelis species, wing, showing some variation encountered. 6. G. ventralis Schiner, 1867 (Vaalbos National Park) microtrichial colours results in central parts of cells appearing darker than areas adjacent to veins. 7. G. cuthbertsoni sp. n. (Angwa Bridge) showing very weak spotting at forks and crossveins.8. G. punctipennis Engel, 1925 (10 km W Garies) showing strong spotting at forks and crossveins. 9. G. melas sp. n. (31 km N Sutherland) showing generally dark wings caused mainly by black microtrichia.