Microphontes safra Londt, 1994

Markee, Amanda & Dikow, Torsten, 2018, Taxonomic revision of the assassin-fly genus Microphontes Londt, 1994 (Insecta, Diptera, Asilidae), African Invertebrates 59 (2), pp. 195-237 : 195

Microphontes safra Londt, 1994 Figs 3-4, 44-49, 64-65, 72

Microphontes safra Londt, 1994: 87.

Diagnosis.

The species is distinguished from congeners by the more or less square abdominal tergites, the short macrosetose dorsal anepisternum, the setose ante- and postpronotum, the overall orange colouration and white pubescence and the apubescent female abdominal tergite 8.

Redescription.

Head: wider than high, brown; vertex and compound eyes at same level; facial swelling indistinct, only lower facial margin slightly developed, silver pubescent; mystax white macrosetose, restricted to lower facial margin, short, reaching tip of proboscis; ommatidia of same size; postgena posterior margin simple, smooth; frons (at level of antennal insertion) slightly diverging laterally, greyish-brown pubescent, light brown macrosetose; ocellar tubercle greyish-brown pubescent, light brown setose; vertex greyish-brown pubescent, yellowish to light brown macrosetose; median occipital sclerite (m ocp scl) with several yellowish macrosetose; postocular (pocl) setae slightly angled anteriorly distally, yellowish macrosetae; occiput predominantly grey pubescent, yellowish setose; compound eye posterior margin (in lateral view) straight or slightly curved throughout.

Proboscis and maxillary palpus: proboscis straight, brown; postmentum plate-like, straight, ventral margin entirely smooth, white setose ventrally; prementum circular, with dorso-median flange, asetose; labella reduced, fused to prementum only ventrally, only forming distal tip of proboscis, rounded; maxillary palpus orange, two-segmented, long yellowish setose, cylindrical; stipites fused medially, but with V-shaped indentation, apubescent, long white setose.

Antenna: orange, lightly grey pubescent; scape 1.5 × as long as pedicel, short and long yellowish setose and macrosetose ventrally; pedicel short yellowish setose ventrally and dorsally; postpedicel cylindrical (same diameter throughout), 1.5 × as long as scape and pedicel combined, asetose; stylus comprised of 1 element, 0.28 × as long as postpedicel, asetose; apical seta-like sensory element situated apically on stylus.

Thorax: brown, postpronotal lobes and lateral scutum orange to light brown; prosternum white pubescent, separated from proepisternum, square to rectangular in shape (straight dorsally); proepisternum white pubescent, long yellowish macrosetose; cervical sclerite long white setose; antepronotum white pubescent, short yellowish setose and long yellowish macrosetose; postpronotum white pubescent, predominantly yellowish setose, long yellowish macrosetose antero-laterally, rarely long yellowish macrosetose sub-laterally and laterally; postpronotal lope short and long yellowish macrosetose; pleuron white pubescent; proepimeron short yellowish macrosetose anteriorly; anepisternum short white setose dorsally, supero-posteriorly short white setose (indistinguishable from other dorsal anepisternal setation); anterior basalare short yellowish setose dorsally, posterior basalare asetose; anepimeron asetose, katepisternum predominantly asetose, postero-dorsally yellowish setose, katepimeron asetose, katatergite white setose and long yellowish macrosetose, meron + metanepisternum asetose, metakatepisternum asetose, metepimeron asetose, anatergite asetose; scutum white to greyish pubescent, scutum setation: short yellowish setose, setae with small sockets, 2 npl setae, 2-3 spa setae, 2 pal setae, 3-4 long yellowish postsutural dc macrosetae, acr setae short yellowish presuturally and postsuturally, median posterior scutum (between dc setae) asetose; scutellum grey pubescent, ds sctl setae absent, ap sctl setae present, 4-6 long yellowish macrosetae; postmetacoxal area entirely membranous.

Leg: orange to light brown, apubescent, all setae circular in cross section; pro coxa orange to light brown, white pubescent, white setose and macrosetose; pro femur orange to light brown, short white setose, yellowish macrosetose: 1 antero-dorsal proximally, 1 antero-dorsal distally, 2 dorsal distally; pro tibia orange to light brown, short white setose, yellowish macrosetose: 4 in 1 antero-dorsal row, 4 in 1 dorsal row, 4 in 1 posterior row, 3 in 1 postero-ventral row, distal tip with 3-4 long yellowish macrosetae; mes coxa orange to light brown, white pubescent, yellowish macrosetose; mes femur orange to light brown, short white setose, yellowish macrosetose: 1 antero-dorsal proximally, 1 antero-dorsal distally, 1-2 dorsal distally; mes tibia orange to light brown, short white setose, yellowish macrosetose: 4 in 2 dorsal rows, 3 in 1 antero-ventral row, 3 in 1 postero-ventral row, distal tip with 5 long yellowish macrosetae; met coxa orange to light brown, white pubescent, white setose and yellowish macrosetose, anteriorly without any protuberance; met trochanter yellowish macrosetose, cylindrical, medially without any protuberance; met femur orange to light brown, short white setose, yellowish macrosetose: 2-3 in 1 anterior row, 2 distal dorsally, 3 apical dorsally; met tibia orange to light brown, straight, short white setose, yellowish macrosetose: 4 in 1 anterior row, 3 in 1 antero-ventral row, 4 in 1 dorsal row, distal tip with 6 long yellowish macrosetae; proximal pro, mes and met tarsomeres longer than following 2 tarsomeres combined, proximal met tarsomere as wide as following tarsomeres; pro tarsomeres 1-5 white setose dorsally, tarsomeres 1-4 long yellowish macrosetose disto-laterally and disto-dorsally, tarsomere 5 weakly yellowish macrosetose distally; mes tarsomeres 1-5 white setose dorsally, tarsomeres 1-4 long yellowish macrosetose disto-laterally and disto-dorsally, tarsomere 5 weakly yellowish macrosetose distally; met tarsomeres 1-5 white setose dorsally, tarsomeres 1-4 long yellowish macrosetose disto-laterally and disto-dorsally, tarsomere 5 weakly yellowish macrosetose distally; pulvilli well-developed (as long as claw); claw abruptly angled distally, pointed; empodium setiform, approximately ½ length of claw.

Wing: 4.1-5.0 mm.

Abdomen: shape regular, T2-3 somewhat square (length to width ratio = 1:1.2), orange to light brown, tergites smooth, setae with small sockets only; T1 white setose, postero-laterally long white macrosetose, grey pubescent, anterior ¼, except laterally, membranous, dorsal surface smooth, without protuberances; T2-8 entirely sclerotised, orange to light brown, white pubescent: in dorsal view appearing apubescent medially (area broader proximally), in lateral view appearing apubescent on entire dorsal surface (only lateral-most margin pubescent), short white setose, long white setose antero-laterally on T2, marginal macrosetae absent from T2-8, medial macrosetae absent from T2-8; S1-8 orange to light brown, lightly grey pubescent, short white setose.

Female: T6-7 grey pubescent, T8 apubescent, setation directed anteriorly on T6-7 and dorsally on T8; postero-paramedian T8 pores present, indistinct, opening not elevated above tergite surface; T8 without any internal apodeme anteriorly; T10 divided into 2 heavily sclerotised acanthophorite plates, with 6, dark brown acanthophorite spines per plate; 3 spermathecae, all equally large, reaching posterior end of segment 6; common spermathecal duct very long, extending well-beyond tip of genital fork ( S 9, furca), individual spermathecal ducts short; spermathecal reservoirs formed by more or less expanded ducts to sac-shaped reservoir, heavily sclerotised; genital fork ( S 9, furca) formed by single, inverted Y-shaped sclerite, median sclerite (at posterior tip) absent, anterior apodeme present, short plate-like apodeme.

Male (Figs 64-65): T1-T8 and S1-S8 entire (without modifications); hypopygium dark brown, rotated by 90°; hypandrium well-developed, triangular, posterior margin with long postero-median projection; gonocoxal apodeme present, short, entirely confined to hypopygium; phallus very short, tip at level of origin of gonostyli, 1 phallic prong, tip pointed, without any protuberance.

Type locality: NAMIBIA: Hardap: Aandster Farm, 25°21'34"S, 016°06'04"E (-25.35944, 16.10111).

Material examined.

NAMIBIA: Hardap: 2♀ 1♂ Aandster Farm , 25°21'34"S, 016°06'04"E, 1000 m, 1974-02-16, vegetated dune and grassland, Irwin, M. (1♂ Holotype NMSA-DIP-4769 , 2♀ Paratypes NMSA-DIP-74617 , NMSA-DIP-74618 , NMSA) ; 1♂ Aandster Farm , 1974-02-17, Lyneborg, L. (Paratype NHMD289337 , ZMUC) ; 1♂ Namib-Skeleton Coast National Park, Sesriem, Elim Dune , 24°27'28"S, 015°46'37"E, 826 m, 2012-02-09, dune, perching on sand, Dikow, T. ( USNMENT00832231 , USNM) .

Distribution, biodiversity hotspots, phenology and biology.

Known from two localities in Namibia (Fig. 72). A rarely collected species known only from three collecting events (Table 1). Adult flies are active in summer in a summer rainfall region on the eastern edge of the Namib Sand Sea (Table 2). Not known to occur in any biodiversity hotspot. Biological data available pertain to the habitat and perching behaviour. All specimens have been collected on partly vegetated sand dunes (Figs 3-4) and data for one specimen indicate that the species perches directly on the sand.

Remarks.

A photograph of this species was erroneously included by Londt and Dikow (2017) (their figures 91-92, specimen USNMENT00832231) under the genus Afroholopogon Londt, 1994, which was a misidentification by T. Dikow at the time. The original type series of M. safra collected on the Aandster farm (now part of the NamibRand Nature Reserve) originates from two collecting events on a joint expedition by Drs Mike Irwin (3 specimens) and Leif Lyneborg (1 specimen). These specimens were collected on separate dates and, at separate sites on the Aandster farm as co-ordinates in the quarter-degree system ( Larsen et al. 2009), were provided on the label as 2516Ac (M. Irwin) and 2515Bd (L. Lyneborg). Since it is impossible to decipher the exact location of the dunes from these co-ordinates, we plot a single locality (25°21'34" S, 016°06'04" E) for all specimens.