Synolcus argentius Londt, 1990

Londt, Jason G. H., 2012, The genus Synolcus Loew, 1858, with descriptions of new species (Diptera: Asilidae), African Invertebrates 53 (2), pp. 661-661 : 672-674

Synolcus argentius Londt, 1990

Figs 4 , 26–29 , 77 , 88

Synolcus argentius: Londt 1990: 3–7 , figs 9–12 (♂ gen.), 13 (♀ gen.).

Redescription:

Male.

Head: Dark red-brown to blackish, strongly silver pruinose, white and black setose. Antenna: Dark red­brown to blackish, fine silver­gray pruinose, scape and pedicel black setose, postpedicel may have some tiny yellow setae dorsally; mean segmental ratios (n= 5) 1:0.8:1.6:1.0 (0.2:0.7:0.1), i.e. pedicel slightly shorter than scape, postpedicel about 1.5 times length of scape, stylus about as long as scape. Face: Blackish, strongly silver pruinose. Mystax white (rarely with few black setae dorsomedially), setae better developed ventrally. Frons and vertex: Blackish, weakly silver pruinose, frons white setose laterally (rarely with few black setae), ocellar tubercle black setose. Occiput: Blackish, strongly silver pruinose, black (dorsally) and white (centrally and ventrally) setose. Thorax: Dark red-brown to blackish, silver to silver-gold pruinose, black, pale yellow and white setose. Prothorax: Dark red-brown to blackish, silver-gold pruinose, white setose (macrosetae pale yellow). Mesonotum: Dark red-brown to blackish, silver-gold pruinose, macrosetae mostly black (may have few pale yellow), minor setae short blackish (mainly anteriorly) and longish whitish (mainly posteriorly). Macrosetae (mostly black or with few pale yellow): acr and dc moderately developed posterior of transverse suture only, 2 npl, 1–2 spal (usually 1 strong, 1 weak when present), 1–2 pal (1 strong, 1 weak or absent). Scutellum: Dark red-brown to blackish, silvery-gold pruinose, disc black and white setose, 1 pair black (or rarely pale yellow) apical macrosetae. Pleura: Uniform dark red-brown to black, silver to silver-gold pruinose, weakly white and pale yellow (ktg) setose. Legs: Cx dark red-brown to black, silver pruinose, white setose; cx 3 with 3 lateral macrosetae. Tro orange-brown, largely apruinose, weakly white setose. Fem uniform dark red-brown to black, major setae mostly pale yellow (few black), minor setae mostly short white. Tib brown with dark red-brown distal ends, major setae mostly pale yellow (few black), minor setae white. Tar dark red-brown, major and minor setae black and pale yellow. Wing ( Fig. 4 ): Veins mostly dark red-brown, anterior veins more orange-brown, membrane transparent, wing tip dark stained. Cell sc with sc–r. Cells r 1 and r 2+3 slightly expanded and displaying corrugations. Wing length× breadth (mean, n=5) 7.6 (6.1–8.4) × 2.7 (2.2–3.1) mm. Haltere: Brown-orange with pale brown proximal end.

Abdomen: Dark red-brown to black, strongly silver pruinose, pale yellow, black and white setose. T1 fairly uniformly silver pruinose, 4–5 pale yellow macrosetae laterally accompanied by many white setae, medially short white (few black) setose. T2–8 mostly silver pruinose but usually with darker areas laterally (depending on angle of view), setae mostly white laterally and posterolaterally (including 1–3 macrosetae), mostly short black anteromedially. S similar to T but uniformly silver pruinose, white setose. Terminalia ( Figs 26–29 ): Epand in lateral view ( Fig. 26 ) almost 3 times as long as deep, with fairly broadly rounded distal tip; epand lobes in dorsal view ( Fig. 27 ) fairly narrowly separated proximally. S8 well-developed, thickly setose along posterior margin and projecting distally as broad dorsoventrally flattened lobe (in ventral view) that largely hides from view both hypd and goncx ( Fig. 28 ). Hypd poorly developed. Gonst in lateral view short, deep with two lobes dorsally ( Fig. 29 ). Aed highly sinuous ( Fig. 26 ).

Female: Essentially similar to male. Wing length × breadth (mean, n =5) 8.2 (6.6–8.9)× 2.6 (2.2–2.8) mm (females slightly bigger than males). Wing tip weakly stained to transparent. 1♀ has two subcostal crossveins. Terminalia ( Fig. 77 ) similar to acrobaptus : Ovipositor laterally compressed, knife-like, elongate (a little more than twice as long as deep).

Type material examined: SOUTH AFRICA: 3♀ paratypes ‘ Sth Africa: Cape Prov / Richtersveld 2816DA / 1 km E of Grootderm / 2.ix.1983 J. Londt & B. Stuckenberg Foot / of small hill’ ; 3♂ 3♀ paratypes ‘ Sth Africa: Cape Prov / Richtersveld 1 km N / Kuboes 1.ix.1989 200m / 28°25'30"S 16°59'30"E / J. Londt B Stuckenberg / P. Croeser Rocky E / slope Euphorbia scrub’ ; 1♂ holotype 1♂ 9♀ paratypes ‘ Sth Africa: Cape Prov / Richtersveld 5 km NE / Grootderm 1.ix.1989 / 28°31'00"S 16°38'00"E / J. Londt B Stuckenberg / P. Croeser 50m Sandy / slope Euphorbia scrub’ .

Other material examined: NAMIBIA: 1♀ Bethanie , Barby 26 [25°51'S 16°33'E], 2–7.x.1972, Strauss, Coetzee & Penrith ( NMNW) ; 1♂ Bethanie , Riverside 135 [26°36'S 16°56'E], 23–26.x.1971, Penrith, Coetzee & Olivier ( NMNW) ; 1♀ Bethanie , Churutabis 108 [27°26'S 17°28'E], 4–12.x.1972, Mokgoabone et al. ( NMNW) ; 1♂ Namuskluft 88 [27°48'S 16°52'E], 7–15.x.1970, Penrith & Coetzee ( NMNW) . SOUTH AFRICA: 1♂ 2♀ 5 km NE Grootderm , 28°29'52"S 16°39'25"E, 90 m, 27.viii.2002, Londt, sandy & rocky ridge with succulents ; 1♀ Port Nolloth [29°15'S 16°52'E], i.[18]91 ( SAMC) .

Note: Londt (1990) transferred the four specimens in NMNW, recorded ten years earlier ( Londt 1980), to this species. With the discovery of namibiensis these Namibian specimens probably need re-examination. Distribution , phenology and biology: Restricted to the north-western parts of South Africa and southern Namibia ( Fig. 88 ), being recorded from the Northern Cape province and a few localities in southern Namibia. Adults fly mainly from August to October (Table 1). While a single female is recorded from Port Nolloth , collected in January, the identification requires confirmation. Label data and personal experience indicate that the flies rest on low vegetation and on the ground (sandy and rocky) .

Figures

Figs 2–14. Synolcus species,♂ wing venation:(2) S.acrobaptus (Wiedemann, 1828) (Gydo); (3) S.amnoni Londt, 1990 (Nkhandla); (4) S. argentius Londt, 1990 (5 km NE Grootderm); (5) S.armstrongi sp.n. (Karkloof paratype); (6) S. aurulentus Engel, 1929 (Outeniqua); (7) S. dubius (Macquart, 1846) (Ntumeni); (8) S. griseus Engel, 1927 (Entabeni); (9) S. macrocercus sp. n. (Middelpos paratype); (10) S. malawi Londt, 1990 (Lichenya paratype); (11) S. minor (Bromley, 1947) (Melmoth); (12) S. namibiensis sp. n. (Ai-Ais paratype); (13) S. spinosus Londt, 1980 (Gladdespruit paratype); (14) S. ukhahlamba sp. n. (Monks Cowl holotype).

Figs26–29.Synolcusargentius Londt,1990,male genitalia (1 kmN Kuboes):(26)lateral (showing aedeagus shape as seen through other organs), (27) dorsal, (28) ventral, (29) gonostylus. Scale line 1 mm.

Figs 76–86. Synolcus species, ovipositor: (76) S. acrobaptus (Wiedemann, 1828) (Cape Town); (77) S. argentius Londt, 1990 (5 km NE Grootderm, redrawn from Londt 1990); (78) S. armstrongi sp. n. (Karkloof paratype);(79) S.aurulentus Engel,1929 (Knysna Forest, redrawn from Londt 1980); (80) S. dubius (Macquart, 1846) (Coffee Bay, redrawn from Londt 1980); (81) S. grieseus Engel, 1927 (Entabeni,redrawn from Londt 1980); (82) S.macrocercus sp.n.(Worcester paratype);(83) S. minor (Bromley, 1947) (Ngome, redrawn from Londt 1990); (84) S. namibiensis sp. n. (Ai-Ais paratype); (85) S. spinosus Londt, 1980 (Gladdespruit paratype, from Londt 1980); (86) S. ukhahlamba sp. n. (Injasuti paratype). Scale lines 1 mm.

Fig.88.The distributions of species in the Synolcus acrobaptus species-group (excluding S. malawi Londt, 1990):S.acrobaptus(Wiedemann,1828) – squares,S.argentius Londt,1990 – circles,S.macrocercus sp. n. – triangles, S. namibiensis sp. n. – diamonds.