Acnephalomyia leukoros, Londt, 2010

Londt, Jason G. H., 2010, A review of Afrotropical Acnephalum Macquart, 1838, including the reinstatement of Sporadothrix Hermann, 1907 and descriptions of two new genera (Diptera: Asilidae: Stenopogoninae), African Invertebrates 51 (2), pp. 431-431 : 453-455

Acnephalomyia leukoros sp. n.

Figs 44–46 , 67

Etymology: From Greek leukos (white) and oros (mountain); noun in apposition. The name refers to the type locality of Witteberge, Afrikaans for ‘white mountains’.

Description (Based mainly on holotype. Condition: Good; slightly greasy, pruinescence not visible):

Head: Dark red-brown to black, white setose. Antenna: Orange-brown, distal tip of style yellow; white setose. Segmental ratios 1.0:1.3:4.4:0.3:1.7 – scape shorter than pedicel; setae of pedicel as long or longer than postpedicel; postpedicel almost twice as long as scape and pedicel combined; style 2-segmented and tipped with spine, almost equal in length to scape and pedicel combined. Face dark red-brown to black, mystax fine white, covering entire face. Frons, vertex and postocular region dark red­brown to black, white setose; angle subtended by eye margins at level of frons/vertex c. 7°. Proboscis dark red-brown, white setose, slightly downturned distally. Palpus 2-segmented, white setose, second segment pointed distally.

Thorax: Dark red­brown to black, mostly white setose. Pronotum mostly fine white setose, but with transverse row of long translucent, white macrosetae. Mesonotum mostly white setose. Lateral macrosetae moderately well developed, mostly white (pale yellow anteriorly) 5 npl, 2 spal, 4–5 pal. Pleura largely asetose except for numerous, long, terminally wavy, pale yellow katatergals, dorsally situated anepisternals and a few tiny white katepisternals. Scutellum shiny dark red-brown to black, apruinose, with weakly developed transverse, subapical groove. 12 moderately developed translucent white apical macrosetae accompanied by some slightly shorter, fine, white setae; disc fine white setose. Legs: Mostly brown-orange, but parts of fem and tib dark red-brown dorsally. Major setae erect, yellowish, minor setae recumbent, white. Ventral parts of tar and terminal end of tib short, black setose. Claws black, longish (but shorter than tarsomere 5); empodia slender, yellow, about half length of claws; pulvilli small (about half length of empodium). Haltere pale yellow, base darker. Wing: 4.9× 2.1 mm. Veins orange-brown, membrane lacking microtrichiae, transparent (unstained); vein R 4 with weakly developed basal stump-vein.

Abdomen: Dark red-brown to black, mostly white setose. Terga apruinose but entirely pitted by setal sockets. Terga with mostly white (a few dark red-brown) setae laterally. White setae extend along distal margins of terga gradually becoming shorter medially; each tergum with small group of white setae anteromedially. Large areas of terga appear asetose, but are covered with tiny dark red-brown setae. Sterna dark red-brown, sparsely long, white setose. Terminalia largely withdrawn between T6 and S6, distal parts somewhat obscured by setae. Genitalia (topotypic paratype male, Figs 44–46 ): Epand reduced, less than half length of outer lobe of goncx, distally broadly rounded and shallowly incised. Proc somewhat straight, jutting out well beyond epand (lateral view) and to similar level attained by outer lobe of goncx. Exterior lobe of goncx suboval in shape, tapering distally to a small pointed, finger­like projection; interior lobe of characteristic shape, longish, terminally dorsoventrally flattened (i.e. broad in dorsal view), jutting out to similar level as achieved by hypd. Hypd somewhat truncate basally, greatly constricted laterally before midlength, tapering to long, distally clavate medial lobe.

Variation: Paratype males are similar to the holotype. Female paratypes range in size with wing lengths of 4.0–6.0 mm (mean 5.0 mm). Females are similar except for the following features: Antennal postpedicel and proximal half of style dark red-brown; dorsal face, entire frons and vertex (not ocellarium) and most of postocular region silver pruinose; mesonotum with clumps of brown setae; mesonotal macrosetae brown-yellow; scutellum with 9–14 (mean 11) apical macrosetae ranging in colour (pale white to light brown); wing may be weakly yellow to pale brown stained basally and at crossveins.

Holotype: SOUTH AFRICA: ♂ ‘ S Africa: W Cape #38 / Witteberge ca. 7 km / W of Constable 870m / 33°17'54"S: 20°19'24"E / 12 xi.1998 J.G.H. Londt / Sandy soil/ Succulents’ ( NMSA).

Paratypes: 2♂ 2♀ ‘ Bulhoek [32°01'S: 18°47'E] / Klaver – Clanw [between Klawer & Clanwilliam].’ ~ ‘ Mus. Expd. / Oct. 1950 ’ ( SAMC) ; 2♀ ‘ South Africa: W Cape / Kagga Kamma Nat. Res. / 32°45.15'S: 19°34.21'E / 22­23 xi.2008 J & A Londt / 1075m Sandy area with / tall fynbos near houses’ ( NMSA) ; 1♂ 1♀ ‘ Constable [33°16'S: 20°18'E]’ ~ ‘12.1962, / S.A.M.’ ( SAMC) ; 1♂ 3♀ same data as holotype ( NMSA) ; 3♂ 1♀ ‘ Verkeerde Vlei [Verkeerdevlei, 33°20'S: 19°52'E]’ ~ ‘12.1962, / S.A.M.’ ( SAMC) ; 1♂ ‘ Matroosberg Sta. [33°25'S: 19°50'E]’ ~ ‘12.1962, / S.A.M.’ ( SAMC) ; 1♂ ‘ Bloutoring [33°30'S: 20°14'E] Sta. / (30 m. E. of / Touws R.)’ ~ ‘12.1962, / S.A.M.’ ( SAMC) ; 1♂ ‘ Swept from / manure heap / Elsenberg [33°50'S: 18°50'E] / 24.2.15’ ( SANC) .

Distribution, phenology (Table 3) and biology: Known from eight localities in the Western Cape of South Africa ( Fig. 67 ). Adults have been collected in October, November and December and are therefore summer active. Specimens were found resting on sandy ground.

Similar species: Male genitalia similar to dorsalis , eremia , probolos and platygaster but the highly distinctive flanged, interior lobes of the gonocoxites easily separate leukoros from these species. Females, unless associated with males, are difficult to separate from those of other species.

Figures

Figs 44–51.Acnephalomyia male terminalia:(44–46) A. leukoros sp. n.paratype, lateral,dorsal and ventral; (47–49) A.platygaster (Loew, 1858) topotypic ♂ lateral, dorsal and ventral; (50, 51) A. probolos sp. n. paratype, lateral and ventral. Scale lines = 1 mm.

Fig.67. Distribution of Acnephalomyia species:A. leukoros sp. n.– triangles; A.platygaster (Loew,1858)– circles.