Empis (Empis) namibiensis Kustov et Shamshev, 2022

Kustov, S. Yu. & Shamshev, I. V., 2022, Three new species of empidid dance flies of the genus Empis Linnaeus, 1758 (Diptera: Empididae) from Namibia, Russian Entomological Journal 31 (2), pp. 194-200 : 196-198

Empis (Empis) namibiensis Kustov et Shamshev , sp.n.

Figs 4–6 .

TYPE MATERIAL. Holotype ♂, Namibia, Windhoek env., 22.545°S 17.255°E, 1870 m, 28–31.i.2021, N. Vikhrev ( ZMMU) . Paratypes: 11♂ 3♀, same data as holotype ( ZMMU, 1 ♂ — ZISP) .

DIAGNOSIS. A species of E. (E.) setitarsus -group; body about 4.5 mm; proboscis long, labrum 1.5–2X as long as head height; laterotergite with pale setae; abdomen densely light grey pruinose, only pale setose; wing with complete veins M 1 and CuA+CuP. Male: wing hyaline. Female: legs with simple setae, wing somewhat broadened and slightly darkened.

DESCRIPTION. Body length 4.5–4.8; wing length 4–4.2 mm. Male ( Fig. 4 ). Head with greyish, dense pruinescence on frons, face (except shiny lower margin), clypeus (except shiny upper margin), ocellar triangle, occiput and postgena; black setose (except noted). Eyes holoptic, with upper ommatidia enlarged. Frons represented by very small, subtriangular space just below ocellar triangle and slightly larger space just above antennae. Face broad, almost parallel-sided, bare. Ocellar triangle with several subequally short, fine setae. Occiput with fine, moderately long postoculars and several similar setae laterally; postgena with numerous long, pale, hair-like setae. Antenna black; scape short, slightly longer than pedicel, both with short setulae; postpedicel elongate-conical, with narrow base and almost straight margins, nearly 3X as long as basal width and 1.5–1.6X longer than stylus. Proboscis moderately long, with labrum nearly 1.5X as long as head height; labium lacking annulations, bearing scattered, minute setulae; labella moderately long, nearly 2X shorter than labrum; with small, dorsal, desclerotized space on about distal third (visible in situ as notch); palpus black, with black, scattered setulae.

Thorax black in ground-colour, densely greyish pruinescent; mesoscutum with 4 brownish vittae (dorsal view), lateral vittae (between dorsocentral and supra-alar setae) less distinct. Proepisternum with 6–7 long, fine, pale setae on lower part and 2–3 similar setae on upper part. Prosternum bare. Antepronotum with 4–5 pale setae on each side. Postpronotal lobe with 1 strong, long, black seta and several fine, pale, short setae anteriorly. Mesonotal setae well-differentiated, black; notopleuron with several short, fine, pale setae anteriorly, sometimes pale setulae present just behind postpronotal lobe: acrostichals rather long, biserial, lacking on prescutellar depression; dorsocentrals irregularly 2–3-serial and similar to acrostichals before suture, uniserial and sparser along prescutellar depression, 2 prescutellar setae longest; 1 fine, moderately long presutural intra-alar, 1 similar presutural supra-alar, 3 long notopleurals, 1 postsutural supra-alar (with 2–3 additional short, fine setae anteriorly), 1 long and 1 minute postalars, 4 scutellars (apical setae long and cruciate, lateral setae short and fine).Laterotergite with numerous pale setae of different lengths. Anterior and posterior spiracles brownish.

Legs long, slender, entirely dark brown, mostly faintly greyish pruinose, coxae densely pruinose, black setose (except noted). Coxae and trochanters mostly with pale fine setae, mid and hind coxae often with some additional dark setae. Fore femur with rows of very short, fine, mostly pale anteroventral and posteroventral setae. Fore tibia with slightly longer setulae posterodorsally and posteriorly; setae of subapical circlet mostly short, fine, 1 anteroventral and 1 posteroventral setae longer. Fore basitarsus slender; fore tarsomeres covered with short setae (except circlet of somewhat longer subapical setae). Mid femur with row of mostly pale posteroventral setae becoming longer toward base of femur (longest setae nearly 1.5X longer than femur basal width). Mid tibia with 4–5 moderately long dorsal (at most 1.5X longer than tibia width) setae and some numerous, slightly shorter setae ventrally (besides circlet of short subapicals). Mid tarsomeres slender, mostly covered with short setae; mid basitarsus with numerous, short, spine-like setae ventrally. Hind femur with mostly very short anteroventral setae (slightly longer closer to apex); long, pale, fine setae on about basal half posteroventrally and posteriorly. Hind tibia slightly almost uniformly thickened viewed laterally (except extreme base), slightly curved viewed posteriorly; with rows of numerous anterodorsal and posterodorsal setae of different lengths (longest setae at most 1.5X as long as tibia middle width), some rather short setae ventrally. Hind basitarsus slightly, uniformly thickened but not broader than apex of hind tibia; with several moderately setae dorsally and numerous short, spine-like setae ventrally.

Wing membrane hyaline, veins brownish; longitudinal veins complete, well sclerotised, only CuA+CuP (anal vein) somewhat weakened beyond midway toward wing margin; cell dm short, with elongate apex. Pterostigma brownish. Basal costal seta present, short, fine. Anal lobe well-developed; axillary incision almost right-angled. Squama yellow, pale fringed. Halter yellow.

Abdomen black in ground-colour, uniformly densely light grey pruinose, tergites with narrowly pale posterior margin; covered with numerous pale hair-like setae longer laterally. Segment 8 with separated sclerites; tergite 8 without projections, entire, somewhat concave posteriorly; sternite 8 broad, desclerotized medially.

Terminalia ( Figs 5–6 ). Epandrium densely greyish pruinose, black setose, divided into two lamellae (dorsal bridge absent); epandrial lamella subtriangular (lateral view), with long setae along upper margin and apically. Hypandrium with basal part faintly greyish pruinose, bearing several moderately long, fine, pale setae; apical part subshiny, yellowish brown; short, in ventral view rather subrectangular, with slightly concave upper margin. Hypoproct slender, digitiform (dorsal view), bare. Phallus yellowish, mostly hidden, short, evenly curved, mostly thick with subapical part narrowed. Ejaculatory apodeme large, extended far beyond basal curvature of phallus, without lateral wings. Cerci black, subshiny, black setose; separated from each other by distinct membraneous space but almost fused narrowly to anterodorsal part of epandrium; cercus somewhat concave posteriorly (lateral view); dorsal lobe subrectangular, short, with short marginal setae; ventral lobe nearly as long as dorsal lobe but very slender, with 2 long setae.

Female. Similar to male except the following characters. Frons broad, parallel-sided; labrum somewhat longer than in male Acrostichals and dorsocentrals shorter. Legs with shorter, simple setation. Wing broader, slightly darkened. Abdomen densely light grey pruinose, covered with shorter setae. Cercus black, long, with scattered hair-like setulae.

REMARKS. Empis namibiensis sp.n. belongs to the E. (Empis) setitarsus -group [ Daugeron, Grootaert, 2003; Sinclair, Daugeron, 2017]. Within the key to species of this group the new species would run to E. namaqua Smith, 1969 and E. corana Smith, 1969 [ Daugeron, Grootaert, 2003]. The new species differs from both these species primarily by pale setae on the laterotergite and abdomen [ Smith, 1969].

ETYMOLOGY. The name of the new species refers to the country of its origin.

DISTRIBUTION. Afrotropics: Namibia.

Figures

Figs 4–6. Empis (Empis) namibiensis, sp.n., ♂, lateral view: 4 — habitus; 5 — postabdomen; 6 — hypopygium. Abbreviations: cerc — cercus; cerc d lb — dorsal lobe of cercus; cerc v lb — ventral lobe of cercus; epand — epandrium; hypd — hypandrium; ph — phallus. Рис. 4–6. Empis (Empis) namibiensis, sp.n., ♂, сбоку: 4 — габитус; 5 — постабдомен; 6 — гипопигий. СокраЩениЯ: cerc — церк; cerc d lb — дорсальнаЯ лопасть церка; cerc v lb — вентральнаЯ лопасть церка; epand — Эпандрий; hypd — гипандрий; ph — фаллус.