Rhabdogaster nuda Loew, 1858

Londt, Jason G. H., 2006, A review of the Afrotropical genus Rhabdogaster Loew, 1858 with descriptions of new species (Diptera: Asilidae: Stenopogoninae), African Invertebrates 47, pp. 243-313 : 269-270

Rhabdogaster nuda Loew, 1858

Figs 65–70

Rhabdogaster nudus Loew, 1858: 351 [1860: 167, 168]; Hull 1962: 212; Oldroyd 1974: 67 (in key), fig. 63

male genitalia; Londt 1993: 385, figs 1 (head), 2 (postmetacoxal area), 3 (wing), 4–6 (ơ genitalia).

Type locality: South Africa (Stellenbosch).

Rhabdogaster nuda: Oldroyd 1980: 367 (catalogue).

Redescription: Londt (1993) provided a redescription of the unique holotype. As that specimen is no longer available (see below), I here provide a description of a Stellenbosch ơ believed to be conspecific. As this ơ shows slight differences in genital form, the illustrations of the holotype provided by Londt (1993) are redrawn here as Figs 65–67 for comparative purposes.

Head: Dark red-brown to black, silver pruinose, white and black setose. Antenna dark red-brown to black, setae black. Face entirely pruinose. Mystax entirely white, occupying approx. lower half of face. Frons pruinose, vertex entirely apruinose (including ocellar tubercle), black setose. Occiput entirely pruinose, white setose. Proboscis and palpi red-brown, setae white.

Thorax: Dark red-brown, silver pruinose, white and black setose. Mesonotum largely pruinose with apruinose stripes and spots centrally. Postpronotal and postalar lobes mostly apruinose. Pleura extensively pruinose with small apruinose spots on an- and katepisternum. Scutellum pruinose except for posterior margin, with approx. 12 long, thin, black sctl s. Postmetacoxal bridge entirely silver pruinose. Legs: cx dark redbrown, silver pruinose, white setose; troc red-brown; fem red-brown (1 and 2 with broad yellow distal ends), white setose; tib and tar brown-yellow, partly white (mainly dorsally) and black (mainly ventrally) setose. Wing 4.1 x 1.3 mm, veins brown, membrane transparent, unstained. Microtrichia present distally, weak to absent proximally. Discal cell lacking microtrichia proximally, costal cell entirely lacking microtrichia.

Abdomen: Dark red-brown, silver pruinose, white and black setose. Tergites pruinose except for posteromedial parts, setae white, but black on apruinose areas. Sternites entirely pruinose, white setose. Terminalia ( Figs 68–70 ): epand in lateral view similar in length to external lobes of goncx and clearly longer than hypd, tapering to narrowlyrounded tips; in dorsal view lobes broadly joined proximomedially; hypd in lateral view curved, shorter than both external lobe of goncx and epand; in ventral view broadlyrounded proximally, tapering rapidly to moderately long, narrow, parallel-sided process with rounded apex. In lateral view external lobe of goncx and gonst extending beyond level reached by outer lobe of goncx.

Variation: A fairly uniform species, but variation difficult to ascertain as most of the material is in poor condition. The identities of females without sympatric males may need future verification.

Holotype: ơ SOUTH AFRICA: Western Cape: ‘ Cap. B. Sp. ’ ( ZMHB).

Note: Londt (1993) studied this specimen, providing a redescription and illustrations of head, postmetacoxal bridge, wing and male terminalia (3 views).Although the specimen was consigned to the postal services, it was not received by the ZMHB and must now be considered lost.

Other material studied: SOUTH AFRICA: Western Cape: 1ơ ‘ South Africa / Stellenbosch [3356S:1851E] / 15.10.1938 / Ac . US.’; 2^‘ South Africa / Stellenbosch / 3–5–1927 / Ac . US.’; 1^‘ South Africa / Stellenbosch / 20 April 1927 / Ac . US.’.2^‘ South Africa: Cape. / Franschhoek 3319CC / Jan Joubertsgat Riv. / J. Londt + B. Stuckenberg / Open veg. + riverbanks’; 2^‘ South Africa / Rawsonville [3341S:1919E] / 10.4.1944 / Ac . US. / JUR’; 1^‘ South Africa / Rawsonville / 11.4.1944 / Ac . US.’; 1?, ‘ South Africa / Robertson [3348S:1953E] / 17.4.1927 / Ac . US.’.

Other material recorded: Oldroyd (1974) records the following as localities for nuda – ‘Mossel Bay; Willowmore; Vanrhynsdorp; Camps Bay. NATAL: Will Grange. RHODESIA: Salisbury, Birchenough Br. (O’Neil)’. With possible exception of the Camps Bay material, which I have not encountered, it is highly unlikely that any of the specimens concerned actually belong to this species. I am unaware of material from either Mossel Bay or Vanrhynsdorp.The only specimens I have seen from Willowmore belong to a distinctive species here described as R. yeti . Will Grange is an abbreviation for Willow Grange, a farming area near Estcourt in KwaZulu-Natal, hundreds of kilometres from the area previously called the ‘Cape of Good Hope’ (Cap. B. Sp.). The two Zimbabwean records are even further away from the Western Cape and must also be rejected as valid localities for R. nuda .

Distribution, phenology and biology (Tables 1, 2): Positively recorded only from South Africa. It is interesting to note that nuda and quasinuda appear to be sympatric at both Stellenbosch and Rawsonville. Collected in April, May and October.

Similar species: R. nitida , oribi sp. n. and pellos sp. n.

Figures

Figs 55–67. Rhabdogaster species, male terminalia: (55–58) R. major Oldroyd, 1970, damaged Mt Ndogo holotype: (55) lateral (left side), (56) dorsal, (57) ventral, (58) lateral (right side); (59–61) R. melas sp. n., Cathedral Peak holotype: (59) lateral, (60) dorsal, (61) ventral; (62–64) R. nitida Hull, 1967, Royal Natal Nat. Park: (62) lateral, (63) dorsal, (64) ventral; (65–67) R. nuda Loew, 1858, ‘Cap. B. Sp.’ holotype: (65) lateral, (66) dorsal, (67) ventral. Scale bars = 1 mm.

Figs 68–79. Rhabdogaster species, male terminalia: (68–70) R. nuda Loew, 1858, Stellenbosch: (68) lateral, (69) dorsal, (70) ventral; (71–73) R. nyx sp. n., Gt. Winterhoek holotype: (71) lateral, (72) dorsal, (73) ventral; (74–76) R.oldroydi (Lindner, 1973), Fish River: (74) lateral, (75) dorsal, (76) ventral; (77–79) R. oresbios sp. n., Cathedral Peak paratype: (77) lateral, (78) dorsal, (79) ventral. Scale bars = 1 mm.