Acnephalomyia iota, 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 : 452-453

Acnephalomyia iota sp. n.

Figs 41–43 , 68

Etymology: From Greek iota (ninth letter of Greek alphabet, anything very small); noun in apposition. The name refers to the small size of the species.

Description (Based on holotype. Condition: Excellent):

Head: Dark red-brown to black, white setose, partly silver pruinose. Antenna: Uniformly dark red-brown, white setose. Segmental ratios 1.0:1.2:4.2:0.2:1.2 – scape slightly shorter than pedicel; macrosetae of pedicel clearly shorter than postpedicel; postpedicel almost twice as long as scape and pedicel combined; style 2-segmented and tipped with spine, clearly shorter than scape and pedicel combined. Face dark red­brown to black, mystax fine white, covering entire face. Frons, vertex and postocular region dark red-brown to black. Frons extensively silver pruinose, white setose (including ocellar tubercle); postocular setae mostly brown (some postocular setae white); angle subtended by eye margins at level of frons/vertex c. 15°. Proboscis short, dark red-brown, brown setose. Palpus 2-segmented, dark red-brown, brown setose.

Thorax: Dark red-brown to black, apruinose. Pronotum mostly brown setose (few white). Mesonotum white setose. Lateral macrosetae well developed, pale translucent white (2 npl, 1 spal, 1 pal). Pleura apruinose, largely asetose except for some, long, white katatergals and dorsally situated anepisternals. Katepisternum asetose. Scutellum shiny dark red-brown apruinose with poorly developed transverse, subapical groove. Four white apical macrosetae accompanied by 2 slightly shorter white setae; disc sparsely white setose. Legs: Red-brown, fem slightly darker. Major setae erect, yellowish, minor setae sparse, recumbent, white. Ventral parts of tar and terminal end of tib short, black setose. Claws black, moderately long (shorter than tarsomere 5); empodia slender, yellow, about half length of claws; pulvilli moderately developed (about length of empodium). Haltere pale yellow, base slightly darker. Wing: 2.7× 1.2 mm. Veins brown, membrane sparsely microtrichose, transparent, unstained. Vein R 4 with weakly-developed basal stump-vein.

Abdomen: Dark red-brown, apruinose, mostly brown setose. Terga broader than long, entirely pitted by setal sockets. T1 with 5 pale translucent white lateral macrosetae, other terga lacking macrosetae, but with a few recumbent white setulae laterally. Sterna sparsely long, white setose. Terminalia withdrawn between T6 and S6. Genitalia ( Figs 41–43 ): Epand reduced, less than half length of outer lobe of goncx, medially deeply incised to form two lobes. Proc somewhat swollen in appearance and jutting out well beyond level achieved by epand (lateral view). Exterior lobe of goncx broadly rounded proximally, tapering distally to a narrowly rounded tip; interior lobe longish, jutting out to about same level as achieved by hypd. Hypd broadly rounded basally, tapering rapidly to moderately long, finger­like, distally projecting, medial lobe.

Variation: ♂ paratype almost identical to holotype but slightly bigger (wing length 2.9 mm). Paratype ♀ similar to holotype except for: Face entirely silver pruinose, mystax entirely white. Frons, ocellarium and postocular region entirely white setose. Mesonotum with silver pruinose margins. Scutellum with 6 apical macrosetae, disc asetose. Legs entirely dark red-brown. Wings 3.3× 1.3 mm; R 4 lacking stump-vein. Except for T1, with 4 lateral macrosetae, abdomen entirely fine brown setose.

Holotype: SOUTH AFRICA: ♂ ‘ South Africa, Cape Prov. / 2mi. [c. 3 km] SW. Brandkop [31°15'S: 19°11'E] 1300ft / Sept. 12, 1972, 3119Ac / ME&BJ. Irwin, Stream bed’ ( NMSA).

Paratypes: NAMIBIA: 1♀ ‘nr. Vogelfederberg [23°06'S: 14°55'E] / Namib Desert / Namibia 13­11­1986 / C. A. Kleinjan’, ‘ Plant-Insect Proj- / Gravel plains 1986 / Site 5 Ar. 12 / D-138’ ( NMSA) . SOUTH AFRICA: 1♂ ‘ Cape Province / 15km N of Nieuwoudtville [31°23'S: 19°06'E] / on road to Loeries­ / fontein, 3–8 x.1989 / F.W. & S.K. Gess’ ( AMGS) .

Distribution, phenology (Table 3) and biology: Known only from the three type specimens collected in Namibia and South Africa ( Fig. 68 ). The two known localities are fairly widely separated and further collecting in the intervening area is therefore desirable. Collected in September, October and November. Found on gravel plains and sandy river beds.

Similar species: A tiny black species not to be confused with any other.

Figures

Figs 35–43. Acnephalomyia male terminalia: (35–37) A. dorsalis (Macquart, 1838) Knersvlakte, North of Vanrhynsdorp, lateral, dorsal and ventral; (38–40) A. eremia sp. n. holotype, lateral, dorsal and ventral; (41–43) A. iota sp. n. holotype, lateral, dorsal and ventral. Scale lines = 1 mm.

Fig. 68. Distribution of species: Acnephalomyia iota sp. n. – diamonds; A. probolos sp. n. – star; Sporadothrix gracilis Hermann, 1907 – circles; Ammodaimon platythrix sp. n. – triangle; Astiptomyia bikos sp. n. – square.