Brachycera Macquart, 1834

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 : 194-196

Suborder Brachycera Macquart, 1834

Superfamily Empidoidea Latreille, 1804

Family Empididae Latreille, 1804

Genus Empis Linnaeus, 1758

How to cite this article: Kustov S.Yu., Shamshev I. V. 2022. Three new species of empidid dance flies of the Empis (Empis) khomasiensis Kustov et Shamshev , sp.n.

Figs 1–3 .

TYPE MATERIAL. Holotype ♂, Namibia, Windhoek env., 22.545°S 17.255°E, 1870 m, 11–15.i.2021, N . Vikhrev ( ZMMU) . Paratypes: 5♂, 3♀, same data as holotype (4♂, 3♀ — ZMMU; 1♂ — ZISP); 2 ♂, 1♀, same locality as holotype, 28–31.i.2021, N . Vikhrev ( ZMMU) .

DIAGNOSIS. A small species of E. (E.) setitarsus -group; body about 3 mm, mesoscutum and abdomen extensively shiny; proboscis short, labrum only slightly longer than head height; thorax and abdomen black setose; M 1 and CuA+CuP incomplete, halter brown. Male: fore and hind tarsomeres 1–3 slightly thickened, tarsomeres 1–4 of all legs clothed in dense long setae.

DESCRIPTION. Body length 2.9; wing length 3.2 mm. Male ( Fig. 1 ). Head with greyish, faint pruinescence on frons, face, clypeus (except shiny upper margin), ocellar triangle, occiput and postgena; black setose. 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 2 very short fine setae and some minute setulae. Occiput with fine, moderately long postoculars and several similar setae laterally; postgena with 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 2X longer than stylus. Proboscis short, with labrum only slightly longer than head height; labium lacking annulations, bearing scattered, minute setulae; labella rather short, nearly 2.5X shorter than labrum; with small, dorsal, desclerotised space on about distal third (in situ visible as notch); palpus black, with black, scattered setulae.

Thorax black in ground-colour, black setose; mesonotum mostly faintly greyish pruinose, prothoracic sclerites (except postpronotal lobe) and mesopleuron densely greyish pruinose; mesoscutum with 2 narrow shiny vittae between rows of acrostichal and dorsocentral setae (situated in pruinose space) and 2 broader, elongate oval, shiny vittae between dorsocentral setae and upper margin of notopleuron (dorsal view), Proepisternum with 5–6 long setae on lower part and 3–4 short fine setae on upper part. Prosternum bare. Antepronotum with 3–4 moderately long setae on each side. Postpronotal lobe with 1 strong, long and several finer and shorter setae. Mesonotal setae well-differentiated: acrostichals moderately long, irregularly biserial, lacking on prescutellar depression; dorsocentrals irregularly biserial and more numerous before suture, uniserial and sparser along prescutellar depression, longer than acrostichal setae, 2 prescutellar setae longest; 1 presutural intra-alar (with 1–2 additional shorter and finer setae), 1 presutural supra-alar (with 1–2 setulae just beyond postpronotal lobe), 3 long notopleurals (with 2–3 setulae anteriorly), 1 postsutural supra-alar (with 1 additional short, fine seta anteriorly), 1 long and 1 minute postalars, 4 scutellars (apical setae long, lateral setae somewhat shorter and finer). Laterotergite with numerous setae of different lengths. Anterior and posterior spiracles brownish.

Legs long, slender, entirely dark brown, mostly subshiny, faintly greyish pruinose, black setose, coxae denser pruinose; covered with almost uniformly fine setae, only mid femur and tibia with slightly stronger setae. Coxae and trochanters with simple setae, fore coxa with numerous setae anteriorly. Fore femur mostly with minute anteroventral and posteroventral setae, some longer setae present closer to base and similar setae on about basal half anteriorly. Fore tibia with numerous long setae dorsally and posteriorly. Fore tarsomeres 1–3 slightly thickened. Mid femur with more or less distinct row of numerous moderately long anterodorsal setae on about basal half; complete row of anteroventral setae, which are long on about basal 2/3 and short, fine on about apical 1/3 (long setae almost 1.5X as long as femur middle width); row of posteroventral setae, which are long on about basal 1/3 and short to moderately long on about apical 2/3. Mid tibia with numerous intermixed moderately long to long setae anterodorsally and posterodorsally (long setae nearly 1.5X longer than tibia width); row of dense, mostly very long anteroventral setae (2.5–3X longer than tibia width); row of less numerous, moderately long posteroventral setae. Mid tarsomeres slender. Hind femur with dense long setae along entire length anteriorly; row of anteroventral setae, which are rather long on about basal 2/3 and short on about apical 1/3; some long setae closer to base dorsally and posteriorly. Hind tibia slightly, evenly thicken toward apex (lateral view) and somewhat curved (posterior view); with dense, long setae anterodorsally and posterodorsally, similar shorter setae anteriorly and anteroventrally. Hind tarsomeres 1–3 slightly thickened. Tarsomeres 1–4 of all legs clothed in dense long setae.

Wing membrane hyaline; veins mostly brownish, somewhat paler proximally, well sclerotised; M 1 and CuA+CuP incomplete; cell dm short, with slightly elongate apex. Pterostigma absent. Basal costal seta absent. Anal lobe welldeveloped; axillary incision right-angled. Squama brownish, black fringed. Halter brown.

Abdomen black in ground-colour, mostly almost shiny, very faintly greyish pruinose; segment 1, extreme anterior margin of segment 2, entire segments 7 and 8 denser pruinose; covered with numerous black, fine setae longer laterally. Segment 8 with separated sclerites; tergite 8 without projections, entire, rather long, with straight posterior margin, bearing 6–7 moderately long posteromarginal setae; sternite 8 broadly desclerotized posteriorly and narrowly on anterior part medially.

Terminalia ( Figs 2–3 ) concolorous with abdomen (except noted), black setose. Epandrium divided into two lamellae (dorsal bridge absent); epandrial lamella subtriangular (lateral view), with numerous long marginal setae (more closely set at apex). Hypandrium short, in ventral view rather subrectangular, bifid apically, with two short, subtriangular projections on upper margin; bare. Hypoproct subrectangular (dorsal view), reaching phallus, bare. Phallus brownish yellow, mostly hidden, short, evenly curved, mostly thick with subapical part somewhat narrowed. Ejaculatory apodeme large, extended far beyond basal curvature of phallus, without lateral wings. Cerci attached to each other anteriorly and almost fused narrowly to anterodorsal part of epandrium; cercus viewed laterally broadly concave; dorsal lobe short, rather digitiform (lateral view), with short setae; ventral lobe viewed laterally very narrow, pointed apically, long, not reaching apex of epandrial lamella; ventral lobe viewed dorsally rather clavate, with apical part flattened and broadly ovate, covered numerous setulae.

Female. Similar to male except the following characters. Frons broad, parallel-sided; labrum slightly longer than in male. Acrostichals and dorsocentrals shorter. Legs with ordinary setation, tarsomeres not thickened.Wing broader, slightly darkened. Abdomen almost shiny covered with shorter black setation. Cercus black, long, with scattered hair-like setulae.

REMARKS. Within the key to species of Coptophlebia from South Africa E. khomasiensis sp.n. would run to E. abrupta Thomson, 1869 [ Smith, 1969]. According to Smith’s [1969: 177] not quite complete re-description of the male holotype of E. abrupta the new species differs from its by somewhat shorter proboscis as well as by shorter anteroventral and posteroventral setae on the mid tibia. In addition, the new species apparently has longer cercus and shorter hypandrium [ Smith, 1969: 178, fig. 213]. Also, the new species could be compared with E. cetywayoi Smith, 1969 , E. vumba Smith, 1969 and E. nigrisquama Smith, 1969 . However, in E. cetywayoi the anal vein is complete whereas both E. vumba and E. nigrisquama have abdominal tergites with yellow setae laterally. The new species shows rather intermediate position between E. (E.) setitarsus and E. (C.) bivittata groups [sensu Daugeron, Grootaert, 2003] due to a combination of a medially desclerotised male abdominal sternite 8 (E. (E.) setitarsus group) and a bifid hypandrium (E. (C.) bivittata group). Provisionally, we placed the new species to the E. (E.) setitarsus group. It has short, simple hypandrium and hypandrial bifid structure may be evolved independently. In species of the E. (C.) bivittata group the hypandrium is massive and uprated in its apical half [ Daugeron, Grootaert, 2003: 342, fig. 2].

ETYMOLOGY. The name of the new species refers to the Khomas Region of Namibia, where it was collected.

DISTRIBUTION. Afrotropics: Namibia.

Figures

Figs 1–3. Empis (Empis) khomasiensis, sp.n., ♂, lateral view: 1 — habitus; 2 — postabdomen; 3 — 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. 1–3. Empis (Empis) khomasiensis, sp.n., ♂, сбоку: 1 — габитус; 2 — постабдомен; 3 — гипопигий. СокраЩениЯ: cerc — церк; cerc d lb — дорсальнаЯ лопасть церка; cerc v lb — вентральнаЯ лопасть церка; epand — Эпандрий; hypd — гипандрий; ph — фаллус.