Acnephalum olivierii Macquart, 1838

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 : 436-438

Acnephalum olivierii Macquart, 1838

Figs 6 , 12, 13, 19 Acnephalum olivierii: Macquart 1838: 51 ; Lehr 1988: 232 (catalogue). Acnecephalum Olivieri: Röder 1882: 245 (misspelling of generic name). Acnephalum Olivierii : Becker et al. 1903: 128 (catalogue); Kertesz 1909: 88 (catalogue) (variant spel-

ling). Acnephalum Olivieri: Engel 1929: 277–279 (fig. 215 head and antenna (Note: fig. 216 tar – not olivierii )).

Macquart’s (1838) description is brief and here replicated in full as a matter of convenience.

1. ACNEPHALUM OLIVIERII , Nob.

Atrum, albido hirsutum. Alis cellula submarginali secunda inappendiculata; postica quarta clausa.

Long. 4½ l.

Moustache, barbe et poils des palpes blanchatres. Pieds moirs, à poils blancs Ailes jaunàtres; quatrieème cellule postérieure fermée au bord intérieur.

De l’ile de Naxos. Olivier. Muséum.

Redescription (Based on holotype. Condition: Poor; mounted on a short pin (I have double mounted the specimen in order to prevent further damage caused by handling). Tip of left antennal style missing, right prothoracic leg broken off beyond halfway down tib, left prothoracic leg broken off from end of tib, right mesothoracic leg broken off beyond trochanter, left mesothoracic leg broken off halfway down fem, right metathoracic leg broken off near tip of fem, left metathoracic leg broken off beyond trochanter. There is a single, complete, but rather dirty, amputated tar, complete with claws and pulvilli, adhering to base of damaged abdomen, that I assume belongs to this specimen. Mesonotum is damaged where pin was inserted. Wings intact, but left wing is dirty (right one is clean and may have been cleaned in relatively recent times). Left haltere is broken off at mid length. Abdomen broken off beyond first segment. None of the missing parts have been preserved):

Head ( Fig. 12 ): Mainly dark red-brown to black, white setose. Antenna ( Fig. 14 ): Dark red-brown, tip of style yellowish. Segmental ratios 1.0:0.9:2.5:0.2:1.0 – scape and pedicel subequal in length, white setose, major setae of pedicel as long as postpedicel; postpedicel only a little longer than scape and pedicel combined; style 2-segmented, spine-tipped, equal in length to scape. Face dark red-brown to black, mystax white, covering entire face. Frons, vertex and postocular region dark red-brown to black, long white setose; angle subtended by eye margins at level of frons/vertex c. 25°. Proboscis dark red-brown, white setose. Palpus 2-segmented, dark red-brown, white setose.

Thorax: Dark red-brown to black, white setose. Pronotum and mesonotum longish white setose. Lateral macrosetae moderately well developed (some broken), partly hidden among general body setae (difficult to count). Pleura with long katatergals, metepisternals and dorsally situated anepisternals. Katepisternals short, sparse. Scutellum shiny black, apruinose, without transverse, subapical groove. 12 moderately developed translucent apical macrosetae; disc asetose. Legs: Dark red-brown, major setae pale yellowish, minor setae longish white. Ventral parts of tar partly black setose. Claws black, shorter than tarsomere 5; empodium yellow (tip missing); pulvillus well-developed (almost as long as claw) ( Fig. 19 ). Haltere dark red-brown. Wing ( Fig. 6 ): 8.8× 3.6 mm. Veins orange-brown, membrane lacking microtrichiae. Membrane transparent, unstained. Vein R 4 lacking basal stump-vein.

Abdomen: Segment 1 dark red-brown to black. T1 with group of pale yellowish macrosetae laterally and tiny dark red-brown setulae medially. Genitalia missing.

Holotype:Sex unknown as terminalia are missing. GREECE: ‘701’, ‘ Acnephalum / olivierii ’ (NMHN). Note: According to Macquart (1838), the type locality is the Greek Island of Naxos (37°05'N: 25°30'E).

Distribution: I have not seen any other material identified as olivierii . In cataloguing the species, Lehr (1988) reported it from Greece (presumably the type material) with queries for the then USSR and North Africa.

Remarks:Although the rather badly preserved type specimen strongly resembles Afrotropical species currently assigned to Acnephalum , it demonstrates features that clearly separate it from these species and align it with Pycnopogon . Features that I believe distinguish it (and other specimens of Pycnopogon , identified by Milan Hradsky listed above) from Afrotropical species covered by this review (i.e. those assigned to the new genus – see below) are shown in Table 1. Although a modern revision of Acnephalum is required before the value of these characters will be known for certain, I believe they serve well to support the taxonomic decisions made here.

Genus Acnephalomyia gen. n.

Etymology: From Acnephalum and Greek myia (a fly). Feminine gender.

Type species: Dasypogon andrenoides Wiedemann, 1828 , by present designation.

As mentioned earlier, with the discovery that the type species of Acnephalum ( A. olivierii , a Palaearctic species) is not congeneric with Afrotropical species, it is necessary to describe a new genus for these species. As these species have had a long history of being called Acnephalum it was decided to retain at least part of the name in providing a new one, hence the choice of Acnephalomyia .

During this study it was further decided to re-establish Sporadothrix as a valid genus, and so species assigned to that taxon are handled separately below. In addition, it was discovered that Acnephalum futile is actually a species of Afroholopogon Londt, 1994 , and so that species is also handled separately under this name. With these adjustments there were actually only six valid Afrotropical species requiring revision at the commencement of this study (i.e. andrenoides , cockerelli , dorsale, platygaster , quadratus , sericeus ).

Diagnosis: Stenopogonine asilids with the following combination of characters. Head: Antennal postpedicel elongate, style composed of 3 elements (2 slender segments and terminal spine-like seta); head clearly wider than high in anterior view (not more or less circular); face slightly convex; mystax long, covering entire face; vertex distinctly excavated; angle of divergence of frons/vertex in anterior view <20°; palpi2-segmented, well-developed; proboscis straight. Thorax: Dorsocentrals undifferentiated; anatergites bare; metepisternal macrosetae absent; postmetacoxal area membranous; pulvilli present, but poorly developed (c. one-third length of claws); wing with cell m 3 open at margin; costal vein extends around wing margin, terminating at A 1 (i.e. anal cell and alula without bordering vein); stump-vein at base of R 4 commonly present, even if rudimentary. Abdomen: Segments clearly wider than long and dorsoventrally flattened; terga commonly long setose laterally; segments 1–6 clearly visible, terminal segments much reduced and withdrawn (often almost hidden from view).

Figures

Figs 6–11. Wing venation (none removed from specimens): (6) Acnephalum olivierii Macquart, 1838, holotype; (7) Acnephalomyia andrenoides (Wiedemann, 1828), lectotype ♂ Dasypogon andrenoides Wiedemann, 1828 (the shadow in the region of the anal cell is a leg situated below the wing); (8) Acnephalomyia platygaster (Loew, 1858), ♂ from 60 km S Aus; (9) Sporadothrix gracilis Hermann, 1907, ♂ from 39 km WNW of Upington; (10) Ammodaimon platythrix sp. n., holotype ♂; (11) Astiptomyia bikos sp. n., paratype ♀.

Figs 12–23.(12, 13) Head in anterior view:(12) Acnephalum olivierii Macquart, 1838,holotype (dotted lines show angle subtended by frons/vertex); (13) Acnephalomyia andrenoides (Wiedemann, 1828), lectotype;(14–18)Antennae,lateral view:(14) A.olivierii holotype;(15) A.andrenoides lectotype; (16) Sporadothrix gracilis Hermann, 1907, ca 65 km SE Noenieput ♂; (17) Ammodaimon platythrix sp. n., holotype ♂; (18) Astiptomyia bikos sp. n., holotype; (19–23) Tarsomere 5 and associated structures: (19) A. olivierii holotype; (20) A. andrenoides lectotype; (21) Sporadothrix gracilis Hermann, 1907, ca 65 km SE Noenieput ♂; (22) Ammodaimon platythrix sp. n., holotype ♂; (23) Astiptomyia bikos sp. n., holotype. Scale lines = 1 mm.