Empis (Anacrostichus) spaetensis Shamshev, 2023

Shamshev, I. V., 2023, Review of the Nearctic species of the subgenus Anacrostichus Bezzi, 1909 (Diptera: Empididae), Russian Entomological Journal 32 (3), pp. 330-355 : 344-346

Empis (Anacrostichus) spaetensis Shamshev , sp.n.

Figs 25–28.

TYPE MATERIAL. Holotype, ♂ labelled: BC. [= British Columbia, Canada] // Bear Mt. / 6.v.20 [no collector name] ( CNC).

Paratype. [hand-written label, locality illegible] May 8.21. W.K.C. (1 ♂, CNC) .

DIAGNOSIS. Rather large species (body about 7 mm); male eyes nearly holoptic; mesoscutum brownish grey pruinose, with 4 brown vittae; acrostichal setae absent; legs with femora and tibiae extensively yellow, fore and mid tibiae with dense, long setae anterodorsally and posterodorsally. Male: abdominal sternite 5 convex medially, bearing two lateral clusters of short strong setae and two short posteromarginal projections.

DESCRIPTION. Body length 6.7 mm, wing length 7 mm (holotype). Male (Fig. 25). Head capsule regions mostly densely, greyish pruinose, black setose; face with shiny upper margin, clypeus almost entirely shiny. Eyes almost touching on frons, upper ommatidia slightly larger. Frons represented by very small subtriangular space just below ocellar triangle and larger space above antennae; with marginal setulae. Face broad, bare. Ocellar setae undifferentiated; several equally short, fine setae present. Occiput covered with long, dense setae (including postoculars); postgena with longer, finer setae. Antenna black; scape nearly 2X longer than subglobular pedicel, both with moderately long setulae; postpedicel nearly 4X as long as basal width; stylus very short, nearly as long as postpedicel basal width. Proboscis with labrum brownish yellow, brown near base; nearly 1.5X longer than eye height; palpus short, brownish yellow; with long, fine, black setae.

Thorax black, mostly densely greyish pruinose; black setose; mesoscutum brownish grey pruinose, with 4 brown vittae (dorsal view) (Fig. 26). Prosternum bare. Proepisternum with numerous long, fine setae on lower part and 2–3 similar setae on upper part.Antepronotum with short setae dorsally and long, fine setae laterally. Postpronotal seta undifferentiated (in holotype) or barely differentiated (in paratype); lobe covered with numerous, moderately long, fine setae. Mesonotal setae (number, position and robustness very variable): acrostichals absent; presutural dorsocentrals arranged in 3 irregular rows, short, fine, postsutural dorsocentrals becoming longer and somewhat broader spread towards scutellum, 2–3 strongest prescutellars; 1 moderately long presutural supra-alar (with numerous additional fine setae); 5–8 notopleurals, 2–3 postsutural supra-alars (with additional fine setae), 1–2 strong and several short fine postalars, 12–14 scutellars (different lengths and robustness, sometimes different number on right and left sides); in addition, numerous short, fine setae present on notopleural depression. Laterotergite with numerous setae. Anterior and posterior spiracles brownish yellow.

Legs long, slender, black setose. Coxae greyish pruinose, remaining podomeres subshiny. Coxae and trochanters with simple setae. Femora without whitish ventral pubescence. Legs colour: coxae and trochanters brownish to yellowish brown; femora almost entirely yellow, only extreme apex (including “knees”) brownish; tibiae mostly yellow, narrowly brownish at apex; basitarsus of all legs mostly brownish yellow to yellow (brown apically), remaining tarsomeres brown. Fore femur clothed with long, mostly fine setae (longer posteroventrally and posteriorly; slightly stronger closer to apex). Fore tibia with numerous, long, mixed fine and strong setae anterodorsally and similar, longer setae posterodorsally and posteriorly. Fore basitarsus thickened; with moderately long, fine setae posterodorsally and posteriorly; bearing scattered, spinule-like setae ventrally. Mid femur with numerous moderately long, strong, irregularly arranged setae on about apical 2/3 (longest setae only slightly longer than femur width); longer and somewhat finer setae on about basal 1/3; spine-like setae on ventral face. Mid tibia mostly with similar setation to fore tibia; bearing spinule-like setae ventrally. Mid basitarsus with spine-like anteroventral and posteroventral setae. Hind femur only slightly broader than mid femur; bearing several moderately long setae anterodorsally and anteriorly closer to apex; mostly moderately long setae anteroventrally (stronger near apex; longer and finer near base); mostly minute setae posteroventrally and posteriorly (long, fine near extreme base); spinule-like and simple setulae on ventral face. Hind tibia simple; slightly, gently thickened towards apex; bearing dense, long setae anterodorsally and posterodorsally; simple setulae ventrally; very short seta in posteroapical comb. Hind basitarsus slender, with 2–3 long, fine anterodorsal and posterodorsal setae; spine-like anteroventral and posteroventral setae.

Wing membrane brownish infuscate; entirely covered with microtrichia; veins brownish, well sclerotized. Veins R 5 and M 1 almost parallel near wing margin; radial fork acute; CuA+CuP (anal vein) complete; cell dm short, with elongate apex; apical portion of M 4 nearly 3X longer than its middle portion. Pterostigma brownish. One–two short, basal costal seta(e). Anal lobe well-developed; axillary incision very acute. Squama yellow, with brownish margin, black fringed. Halter yellow.

Abdomen dark brown, black setose. Tergites 1–5 extensively shiny, narrowly greyish pruinose laterally (broader on tergite 5), tergites 6–8 mostly densely greyish pruinose (tergite 6 with shiny antero-lateral spot); tergites 1–4 with numerous long, mixed fine and strong setae laterally and scattered setulae dorsally (posteromarginal setae hardly distinguishable), tergite 5 with short fine setae, tergites 6–7 with scattered setulae, tergite 8 with moderately long fine setae. Sternites 1–5 densely greyish pruinose, sternite 8 subshiny laterally and greyish pruinose medially; sternites 1–4 and 8 with long setae. Postabdomen: segments 5–8 modified. Tergite 6 and segment 7 bent downwards, accordingly segment 8 and terminalia shifted to ventral position relative to body plane. Tergite 5 with somewhat concave lateral margin. Sternite 5 convex medially; bearing two sublateral clusters of moderately long, strong, black setae and two short, digitiform posterior projections. Tergite 6 slightly asymmetrical; somewhat narrower than tergite 5, with small, rounded antero-lateral tubercle and small posteromarginal lateral projection. Sternite 6 invisible in situ, partly retracted into sternite 5, strongly reduced, bare. Tergite 7 slightly asymmetrical; narrower and 2.5–3X shorter than tergite 6; with small, anteromarginal lateral excavation. Sternite 7 asymmetrical, with few short setae laterally; deeply concave laterally forming two portions broadly separated by membraneous space ventrally; anterior portion (mostly invisible in situ) asymmetrical, including free, strongly sclerotised, small sclerite anteriorly and larger sclerite posteriorly; posterior portion represented by small, weakly sclerotised, lateral subtriangular sclerite. Segment 8 funnel-like, narrowed anteriorly, with entirely separated tergite and sternite; tergite 8 long, nearly as long as tergite 7, undivided, somewhat deflected posteriorly; sternite 8 subtriangular in lateral view, somewhat longer than tergite 8, with simple structure and vestiture.

Terminalia (Fig. 27, 28) moderately large, black setose; epandrium mostly brownish, yellowish brown along lower margin, with long setae closer to lower margin; hypandrium with brown basal portion and brownish yellow apical projections, bearing long setae; cercus brown, with simple setulae; phallus brownish yellow. Epandrium entirely divided medially. Cerci separated with each other and from epandrium; (epandrial bridge absent); epandrial lamella rather subtriangular cercus small, rather subrectangular (lateral view), slightly (lateral view), with broadly rounded apex, bearing long setae broadened posteriorly, with posterior margin extending nearly more numerous closer to lower margin. Hypandrium (Fig. 28) to apex of epandrial lamella; undivided, with smoothed inner separated from epandrium; entirely sclerotised; very prolonged margin; covered with simple dark setulae, bearing scattered and deeply concave posteriorly forming two broad lobes erect setulae on inner surface. Hypoproct weakly sclerotised, excised at apex; bearing numerous strong setae near base; bare. Phallus almost entirely hidden, gently arched; nearly gonocoxal apodeme small. Subepandrial sclerite separated basal 1/3 very thick (lateral view), remaining portion slender.

Figs 25–28. Empis (Anacrostichus) spaetensis Shamshev , sp.n., male: 25 — habitus, holotype, lateral view; 26 — habitus, holotype, dorsal view; 27 — hypopygium, lateral view (setation omitted); 28 — hypandrium, ventral view. Abbreviations: cerc — cercus; ej apod — ejaculatory apodeme; epand — epandrium; goncx apod — gonocoxal apodeme; hypd — hypandrium; ph — phallus.

Рис. 25–28. Empis (Anacrostichus) spaetensis Shamshev , sp.n., самец: 25 — габитус, голотип, вид сбоку; 26 — тоЖе, вид сверху; 27 — гипопигий, вид сбоку (Щетинки не покаЗаны); 28 — гипандрий, вид сниЗу. СокраЩениЯ: cerc — церк; ej apod — ЭЯкулЯторнаЯ аподема; epand — Эпандрий; goncx apod — гонококсальнаЯ аподема; hypd — гипандрий; ph — фаллус.

346 Nearctic species of the empidid subgenus Anacrostichus

Ejaculatory apodeme moderately large, extended far beyond basal curvature of phallus, with lateral wings.

Female. Unknown.

DIFFERENTIAL DIAGNOSIS. Within the key to the North American species of Empis compiled by Coquillett [1895], the new species would run to E. tenebrosa Coquillett, 1895 and E. spectabilis Loew, 1862 . Empis tenebrosa ( USA: Colorado, Texas) remains known after an original description only and its subgeneric position is unclear. The new species differs from E. tenebrosa primarily by entirely black antenna (versus scape and postpedicel reddish) and extensively shiny abdominal tergites 1–5 (versus pollinose). Empis spectabilis belongs to Anacrostichus . This species has densely pruinose abdomen and incrassate hind femora (see below). Within the key provided by Melander [1902], the new species would run to the couplet 56 (2 or 4 scutellar setae). However, the new species has 12–14 scutellar setae.

ETYMOLOGY. The epithet refers to the type locality of the new species ( Bear Mountain , British Columbia ( Vancouver Island ), Canada) that is a traditional mountain area in shared Coast Salish territories. In the Salishan language, “spaet” means “bear” .

DISTRIBUTION. Canada (British Columbia).