Microphontes whittingtoni 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 whittingtoni Londt, 1994 Figs 50-55, 66-67, 72

Microphontes whittingtoni Londt, 1994: 87.

Diagnosis.

The species is distinguished from congeners by the small size with a wing length of 3.1-3.7 mm, distinctly wider than long and transversely rectangular abdominal tergites, entirely setose postpronotal lobes and dorsal and posterior anepisternum (no macrosetae) and features of the male terminalia such as the short postero-median projection on the hypandrium and shape of the gonostyli.

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, grey pubescent, yellowish setose; ocellar tubercle light brown pubescent, light brown setose; vertex greyish-light 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 brown, two-segmented, long yellowish setose, cylindrical; stipites fused medially, but with V-shaped indentation, apubescent, long white setose.

Antenna: light brown, lightly grey pubescent; scape 1.5 × as long as pedicel, short and long yellowish setose and macrosetose ventrally; pedicel short yellowish setose dorsally and long yellowish macrosetose ventrally; postpedicel cylindrical (same diameter throughout), approximately 2 × as long as scape and pedicel combined, asetose; stylus comprised of 1 element, 0.14 × as long as postpedicel, asetose; apical seta-like sensory element situated apically in cavity on stylus.

Thorax: light brown, scutum with median longitudinal stripe and shorter sublateral longitudinal stripes brown; prosternum white pubescent, separated from proepisternum, square to rectangular in shape (straight dorsally); proepisternum white pubescent, long yellowish macrosetose; cervical sclerite long yellowish setose; antepronotum white pubescent, short yellowish setose medially, long and weakly yellowish macrosetose laterally; postpronotum white pubescent, long yellowish setose medially and sub-laterally, long and weakly yellowish macrosetose laterally; postpronotal lope long yellowish setose; pleuron white pubescent; proepimeron long white setose anteriorly; anepisternum long yellowish setose dorsally (setae directed dorsally), long yellowish setose postero-medially (setae directed posteriorly), supero-posteriorly long yellowish setose (indistinguishable from other dorsal anepisternal setation); anterior basalare long yellowish setose medially, posterior basalare asetose; anepimeron asetose, katepisternum asetose, katepimeron asetose, katatergite long yellowish macrosetose, meron + metanepisternum asetose, metakatepisternum asetose, metepimeron asetose, anatergite asetose; scutum white to greyish pubescent, scutum setation: long yellowish setose, setae with small sockets, 1 npl setae, 1 spa setae, 1-2 pal setae, 2-3 long yellowish postsutural dc macrosetae, acr setae long yellowish presuturally and postsuturally, median posterior scutum (between dc setae) long yellowish setose, setae directed anteriorly; scutellum white pubescent, ds sctl setae present, long yellowish setae, ap sctl setae present, 6-8 long yellowish macrosetose; 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, white macrosetose: 2-3 postero-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, 4 in 1 postero-ventral row, distal tip with 3-4 long yellowish macrosetae; mes coxa brown, white pubescent, white macrosetose; mes femur orange to light brown, short white setose, yellowish macrosetose: 2 anterior proximally and medially, 2-3 anterior distally, 4 posterior distally; mes tibia orange to light brown, short white setose, yellowish macrosetose: 5 in 1 dorsal row, 3 in 1 anterior row, 5 in 1 antero-dorsal row, 5 in 1 antero-ventral row, 6 in 1 postero-ventral row, distal tip with 8 long yellowish macrosetae; met coxa orange to light brown, white pubescent, white setose and 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 5 short yellowish macrosetae; proximal pro and mes tarsomere as long as following 2 tarsomeres combined, proximal met tarsomere longer than 2 following tarsomeres combined, proximal met tarsomere as wide as following tarsomeres; pro tarsomeres 1-5 white setose dorsally, tarsomeres 1-4 short yellowish macrosetose disto-laterally and disto-dorsally, tarsomere 5 weakly yellowish macrosetose distally; mes tarsomeres 1-5 white setose dorsally, tarsomeres 1-4 short yellowish macrosetose disto-laterally and disto-dorsally, tarsomere 5 weakly yellowish macrosetose distally; met tarsomeres 1-5 white setose dorsally, tarsomeres 1-4 short 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: 3.1-3.7 mm.

Abdomen: shape compressed, T2-3 distinctly transversely rectangular (length to width ratio> 1:3), orange to light brown, tergites smooth, setae with small sockets only; T1 white setose, postero-laterally long white macrosetose, white pubescent, anterior ½, except laterally, membranous, dorsal surface smooth, without protuberances; T2-8 entirely sclerotised, orange to light brown, white pubescent: in dorsal view T2-7 appearing predominantly apubescent except laterally, in lateral view T2-7 appearing apubescent in posterior ½ except lateral margin, 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: T6-8 grey pubescent, setation directed anteriorly on T6-7 and dorsally on T8; postero-paramedian T8 pores present, indistinct, opening not elevated above tergite surface; T8 with internal rectangular apodeme (entirely fused to T) anteriorly; T10 divided into 2 heavily sclerotised acanthophorite plates, with 6-7, light brown acanthophorite spines per plate; 3 spermathecae, all equally large, reaching posterior end of segment 6; individual spermathecal ducts long; spermathecal reservoirs spherical, heavily sclerotised; genital fork ( S 9, furca) formed by single, inverted V-shaped sclerite, median sclerite (at posterior tip) absent, anterior apodeme absent.

Male (Figs 66-67): T1-T7 and S1-S7 entire, T8 + S8 reduced to ring of sclerites; hypopygium orange to light brown, rotated by 180°; hypandrium well-developed, triangular, posterior margin with short postero-median projection; gonocoxal apodeme present, short, entirely confined to hypopygium.

Type locality: SOUTH AFRICA: Northern Cape: Visrivier (23 km SE Middelpos), 32°01'00"S, 020°25'00"E (-32.01667, 20.41667).

Material examined.

SOUTH AFRICA: Northern Cape: 1♀ 2♂ Visrivier, 23 km SE Middelpos , 32°01'00"S, 020°25'00"E, 1990-11-28, Whittington, A., Londt, J. (1♂ Holotype NMSA-DIP-4777 , Paratypes 1♀ NMSA-DIP-74619 , 1♂ NMSA-DIP-74620 , NMSA) ; 1♀ Fish River bridge, 23 km SE Middelpos , 32°01'25"S, 020°24'24"E, 1145 m, 2008-11-18, sandy riverine scrub area, Londt, J., Londt, A. (NMSA-DIP-74484, NMSA) .

Distribution, biodiversity hotspots, phenology and biology.

Known from two nearby localities in the Northern Cape of South Africa (Fig. 72). A rarely collected species known only from two collecting events (Table 1). Adult flies are active in early summer in a winter rainfall region (Table 2). The species is endemic to the Succulent Karoo biodiversity hotspot. Biological data available pertain to the habitat and indicate that the species occurs in sandy habitats along rivers.

Remarks.

The boundaries of this species have been redefined based on the study of all primary and secondary type specimens originally studied by Londt (1994) and additional specimens collected in the south-western Northern Cape Province. We postulate that M. whittingtoni represents a group of morphologically similar species and we have split the type series into three species. Londt (1994) cleared the male terminalia of two paratype specimens and illustrated one of them in his figures 51-53 (see Figs 68-70). The holotype of M. whittingtoni does not have the long postero-median projection on the hypandrium (see Fig. 66) that was illustrated by Londt (1994) based on the paratype from 23 km N Middelpos (Fig. 68), which now represents the holotype of M. kryphios sp. n. (see also Remarks under M. jasonlondti sp. n.).