Rhamphomyia (Pararhamphomyia) omissinervis Becker

Rhamphomyia (Pararhamphomyia) omissinervis Becker

(Figs 40, 41)

Rhamphomyia omissinervis Becker, 1900: 18. Type locality: Nikander Island, Krasnoyarskiy Territory, Russia.

Rhamphomyia (Pararhamphomyia) omissinervis Becker: Frey, 1922: 36 (key); Frey, 1955b: 490 (revision); Chvála & Wagner, 1989: 303 (catalogue); Shamshev, 2001: 322 (key); Yang et al., 2007: 174 (catalogue); Shamshev, 2016: 67 (checklist).

Rhamphomyia omissinervis Becker: Melander, 1928: 201 (catalogue); Gorodkov & Kovalev, 1969: 620 (key).

Note on synonymy. Becker (1900) included eight specimens in the type series of this species. Only three syntypes were examined and the location of the remaining five syntypes is unknown.

Type material examined. LECTOTYPE (here designated in order to fix identity of the species) ♂ (Fig. 40C), labelled (Figs 40D): “Ins. Nikandr [= Nikander Island, 70°39′N 83°16′E, Krasnoyarskiy Territory, Russia]”; “ J. Sahlb. ”; “256”; “Spec. typ.”; “ Rhamphomyia / omissinervis Beck. ”; “Mus. Zool. H:fors/ Spec. typ. No. 4033./ Rhamphomyia / omissinervis Beck. ”; “ LECTOTYPE / Rhamphomyia omissinervis / Becker/ des. Sinclair & Saigusa 2018 [red label]” (MZH). PARALECTOTYPES: Russia: Krasnoyarskiy Territory: Dudinka, J. Sahlberg (2 ♀, MZH).

Additional material examined. CANADA. Nunavut: Coral Harbour, Southampton Is., 13–20.vii.1948, G.E. Shewell (14 ♂, 29 ♀, CNC); Chesterfield, 1–8.viii.1950, J. R. Vockeroth (2 ♀, CNC); Kukluktuk, 67.78157°, - 115.27824°, Repl.1, wet,, sweep, 3.vii.2011, NBP field party, CCDB-21399-H09, CCDB-21399-H10, CCDB- 21399-H11 (3 ♂, barcoded, LEM); Kukluktuk, 67.83391°, -115.21410°, Repl.2, wet, MT, 3–7.vii.2010, NBP field party (13 ♂, LEM); Kukluktuk, 67.83538°, -115.20987°, Repl.2, mesic, MT, 3–7.vii.2010, NBP field party (8 ♂, LEM); same data except, CCDB-21421-A11, CCDB-21421-C11 (2 ♂, barcoded, LEM); Kukluktuk, 67.77639°, -115.30882°, Repl.3, wet, MT, 7–12.vii.2010, NBP field party (1 ♀, barcode associated, LEM).

Diagnosis. This dark-legged and dark setose species is distinguished from other species of Pararhamphomyia by the yellowish abdominal setae, strong coxal setae; male hind tibia only slightly thickened toward apex, covered with long setae dorsally, hind tarsomere 1 with similar setae, hind tarsomeres 2 and 3 slender; apex of the epandrium is sharply attenuated with slender extension; elongate phallus looping beyond epandrium, curving back to cercus, sharply bent just beyond hypandrium. Females are without pennate leg setae.

Description. Wing length 4.5–4.7 mm. Male. Head dark in ground-colour, with greyish pruinescence on face, frons and occiput. Holoptic, eye with ommatidia larger on upper half and smaller on lower half. Frons represented by very small triangular space below ocellar tubercle and larger subtriangular space above antennae, bare; face almost parallel-sided, slightly divergent towards mouthparts; bare, with oral margin dark, shiny. Ocellar triangle dark, with 1 anterior pair of dark setae and 1 pair of shorter posterior setae; 2 pairs of dark postocellar setae, no longer than posterior ocellar setae. Occiput bearing row of dark and curved postocular setae on upper half of occiput; otherwise setae strong, shorter than postoculars. Postgena bearing dark setae longer and more hair-like than occipital setae. Antenna dark and pruinose; scape slightly longer than pedicel; pedicel bulbous and wider than scape; postpedicel nearly 3X longer than basal width; stylus no longer than basal width of postpedicel. Palpus dark and pollinose, with setulae dark. Clypeus glossy; labrum lustrous and black, longer than head height; labellum dark and bearing several dark setae.

Thorax dark, largely densely grey pruinescent, with 2 faint grey vittae between acr and dc rows. Proepisternum with 3–5 long setae on lower section; upper proepisternum in front of spiracle bare; prosternum bare. Antepronotum with row of short, stout dark setae. Postpronotum with several thin setae and 2–3 stouter and longer pprn. Scutum with biserial acr, shorter than dc; dc uniserial, increasing in length posteriorly, anterior 2–3 setae offset laterally; 1–2 stout presut spal (= posthumeral) and several stout similar setae; notopleuron with cluster of stout setae anteriorly; 4–6 longer, stouter setae posteriorly; 2 prealar setae; 1 psut spal; 1 pal; 2–3 pairs of sctl. Laterotergite with long, pale setae. Anterior and posterior spiracles brown with black outer ring.

Legs entirely dark reddish-brown, shiny, coxae lightly greyish pruinescent. Fore coxa with strong dark setae anteriorly; mid and hind coxae with several dark, strong lateral setae. Fore and mid femora with 1 anteroventral and 1 posteroventral row of setae, stouter and longer on midleg; mid femur with white ventral pile. Hind femur white ventral pile; with anteroventral setae dark, fine, doubling in length on apical half (Fig. 40B). Fore tibia with rows of fine posterodorsal and posterior setae; ventral setae similar, shorter. Mid tibia with long preapical anterodorsal seta, shorter than tarsomere 1; anteroventral and posteroventral rows of stout setae; clothed in long fine setae dorsally. Hind tibia only slightly thickened toward apex, with long, pale setae dorsally, less than 2X tibial width; anteroventral and posteroventral setae no longer than tibial width (Fig. 40B), 1 long seta in posteroapical comb. Hind tarso- mere 1 slightly broader than other hind tarsomeres (Fig. 40B) with long setae dorsally, 2X tarsal width; tarsomere 1 of all legs with stout setae ventrally. Hind tarsomeres 2 and 3 slender, with short setae dorsally, apical setae longer.

Wing faintly infuscate with yellowish veins; all veins complete (except Sc and CuA+CuP), well sclerotized; sometimes cell dm open. Anal lobe well-developed and axillary excision right angled. Pterostigma darker yellow, although faint; basal costal seta absent. Halter pale brown.

Abdomen with thin greyish pruinescence, with reddish-brownish tinges on tergites, posterior margins of segments pale. Abdomen clothed with long, hair-like pale setae, longer laterally. Sternite 8 with many long, pale setae posteriorly, subequal to length of sclerite; margin closely appressed laterally with tergite 8. Tergite 8 length halflength of sternite 8; many fine, pale setae posteriorly, longer laterally.

Terminalia (Fig. 40A) dark, contrasting with exposed pale phallus. Epandrium subtriangular in lateral view, with spine-like setose expansion prior to elongate, apical finger-like projection bearing many long, pale setae; base of epandrium dark brownish-black; epandrium with yellowish patch on concave margin near mid-length; pruinose with ventral margin bearing many fine, pale setae. Cercus tapered apically, one-third length of epandrium; densely pruinose; dorsal margin bearing many fine, short dark setae. Subepandrial lobe tear drop-shaped, elbowed, with stem slimmer than apex; apex bearing several fine setae, longer than setae on cercus; subepandrial lobe longer than cercus. Hypandrium cylindrical, short, ending at base of swollen phallus. Phallus slender and reddish brown; sharply bent just beyond hypandrium, running nearly straight until curved inwards once, forming loop, extending further than length of terminalia, looping back between epandrial lamellae. Ejaculatory apodeme fan-shaped, small, dorsal margin of vertical wing flattened, 2 short lateral wings at base shorter than vertical wing.

Female. Similar to male except frons with several pairs of lateral setulae; leg and abdominal setae much shorter and reduced; legs without pennate setae; wing more darkly infuscate.

Distribution. In North America, this species is known only from the low arctic region along the western shore of Hudson Bay, Southampton Island and Kugluktuk (Fig. 41). In the Palaearctic Region, R. omissinervis is known from eastern Siberia and Far East of Russia (Shamshev 2016).

Remarks. Rhamphomyia (Pararhamphomyia) omissinervis is assigned to the R. lapponica (= rufipes Zetterstedt) species group.