Rhamphomyia sublongiseta Shamshev, Sinclair & Saigusa, 2020

Shamshev, Igor V., Sinclair, Bradley J. & Khruleva, Olga A., 2020, The empidoid flies (Diptera: Empidoidea, exclusive of Dolichopodidae) of the Russian Arctic islands and Svalbard Archipelago, Zootaxa 4848 (1), pp. 1-75 : 54-57

Rhamphomyia sublongiseta Shamshev, Sinclair & Saigusa sp. nov.

( Figs 62–65 )

urn:lsid:zoobank.org:act:99F127D3-A192-4D59-9030-EEEB1F7E3827

Type material. HOLOTYPE ♂, labelled: [ RUSSIA, Chukotka AO ( Wrangel Island )] “[printed in Cyrillic, Russian] bukh. [=bukhta, bay] Somnitelnaya/ south of o. [=ostrov, island] Wrangel/ Gorodkov 19.vii.[1]966”; “on flower/ Dryas integrifolia ,/ spotted/ tundra”; “ Holotypus / Rhamphomyia / sublongiseta Shamshev ,/ Sinclair, Saigusa sp. n. [red label]” (INS_DIP_0000618, ZIN).

PARATYPES: CANADA. Yukon: km 155 Dempster Hwy, 18–20.vi. 1980, 950 m, D.M. Wood & D. Lafontaine (1 ♂, CNC); Richardson Mts , 2800 ft, 66°07′N 136°30′W, 11.vi.1982, D.M. Wood (1 ♂, 1 ♀, CNC) . RUSSIA. Chukotka AO (Wrangel Island): SE part of Wrangel Island, Rogers Bay , tundra, 20.vii.1932, A. Mineev (2 ♂, ZIN); same data as holotype, 19.vii.1966, KBG (1 ♂, 1 ♀, ZIN; 1 ♂, 1 ♀, CNC); environs of Somnitelnaya Bay , south of Wrangel Island , valley of river Somnitelnaya , Mineev Mtns , 150 m, shingle, on flower of Dryas integrifolia , 19.vii.1966, KBG (2 ♀, ZIN); same locality, on flower of Potentilla emarginata , 22.vii.1966, KBG (1 ♀, ZIN); Somnitelnaya Bay , south of Wrangel Island , Mineev Mtns , 400 m, S of Sovetskaya Mtn, 20.vii.1966, KBG (2 ♀, ZIN); 5 km N Somnitelnaya Bay, warmed up on stones river bank, 27.vii.1966, KBG (1 ♀, ZIN); 5 km N Somnitelnaya Bay, valley of river Somnitelnaya , small meadow, 26.vii.1972, KBG (1 ♀, ZIN); environs of Aterton Mtn, 70°59′N 178°41′W, BT B, Sw, 13.vii.2019, OAK (1 ♂, 1 ♀, ZIN) .

Additional material. RUSSIA, Chukotka AO (Wrangel Island): middle flow of river Neozhidannaya , 71°01′N 179°09′E, YPT, BT 1 , 12–16.vii.2016, LFV (10 ♂, 10 ♀, ZIN; 1 ♂, 1 ♀, CULSP); same locality, YPT, BT 2 , 12–16.vii.2016, LFV (37 ♂, 28 ♀ ZIN); Thomas Mtn, 70°56.964′N 178°43.026′E, BT 16 , 10–31.vii.2016, LFV (2 ♂, ZIN) .

Diagnosis. Mid-sized (wing length about 4.5 mm), robust, black setose, blackish brown flies. Male holoptic; hind tibia thickened, hind basitarsus strongly expanded, basal area broader than apex of hind tibia, elongate oval, somewhat narrowed apically, both clothed in very long, dense fine setae; abdominal tergite 8 without projections; cercus truncate at apex (lateral view), with notch slightly beyond middle dorsally; phallus well exposed, slender, gently sinuate near middle. Female wing darker near base, legs without pennate setae.

Description. Body length 4.2–4.7 (holotype 4.7); wing length 4.3–4.5 (holotype 4.4) mm. Male ( Fig. 62 ). Head with dense greyish brown pruinescence on face, frons, postgena, ocellar triangle and occiput; dark setose. Holoptic; upper ommatidia enlarged. Frons represented by very small subtriangular space below ocellar tubercle and larger subtriangular space above antennae, bare. Face broad, bare. Ocellar triangle with several long fine setae. Occiput with numerous long fine setae, including postoculars; postgena with numerous hair-like setae. Antenna blackish brown; scape and pedicel subequally short, both with long fine setae on outer side and short setulae on inner side; postpedicel conical, with straight margins, nearly 3X longer than wide; stylus very short, shorter than postpedicel basal width. Palpus dark; with numerous long, dark fine setae. Proboscis with labrum dark reddish-brown, slightly longer than head height.

Thorax dark in ground-colour, greyish brown pruinescent; with black setation; scutum almost uniformly brownish pruinescent (dorsal view), only some traces of two narrow vittae between rows of acr and dc. Proepisternum with tuft of numerous long fine setae on lower section; upper proepisternum in front of spiracle with numerous similar setae. Prosternum bare. Antepronotum with numerous short setae. Postpronotal lobe with numerous long fine setae. Mesonotal setae hardly differentiated, numerous, long, almost uniformly fine, only some npl, pal, sctl and prescutellar dorsocentrals somewhat stronger; 1–2 pal, 6–10 sctl (usually 6–8); acr long, fine, arranged in 2 irregular rows, lacking on prescutellar depression; presutural dc long, multiserial, not separated by bare space from supra-alar setae, some prescutellars somewhat stronger. Laterotergite with numerous long fine setae. Anterior and posterior spiracles brown.

Legs robust, uniformly dark brown; mostly subshiny, coxae and trochanters with denser greyish pruinescence; black setose. Fore coxa covered with long fine setae anteriorly. Podomeres of fore and mid legs unmodified; hind femur somewhat broader near apical half; hind tibia expanded, slightly arcuate; hind basitarsus strongly expanded, basal area broader than apex of hind tibia, elongate oval, somewhat narrowed apically; hind tarsomeres 2–3 slightly expanded. Mid and hind femora whitish pilose ventrally. Legs mostly covered with fine setae, only mid and hind tibiae with some stronger setae. Fore femur clothed in long setae including anteroventral and posteroventral rows (about as long as femur width); mid femur with row of short anteroventrals and row of short posteroventral setae on basal half and longer on apical half, some short setae near extreme base ventrally; hind femur without setae ventrally, with several long av setae on about apical third (otherwise av minute), with more or less distinct row of long setae anteriorly and some long setae around apex and base. Fore tibia with 2–3 more or less distinct ad (except circlet of short subapicals), covered with moderately long fine setae posterodorsally; mid tibia with 2–3 ad, fine setae posterodorsally (sometimes 1–2 setae somewhat stronger), rows of numerous short spine-like av and pv setae; subapical circlet with 1 long ad seta; hind tibia clothed in very long dense curved setae; 1 seta in posteroapical comb. Fore and mid basitarsi with some longer fine setae posterodorsally, spine-like setae ventrally; hind basitarsus with numerous very long setae dorsally and ventrally (the latter stronger), hind tarsomeres 2–4 with long setae dorsally.

Wing membrane faintly brownish, with brownish veins; all veins complete (except Sc). Pterostigma brownish yellow. Basal costal seta usually present, short (sometimes indistinct). Anal lobe well-developed; axillary incision acute but closer to 90°. Squama brownish, dark fringed. Halter brown.

Abdomen dark, densely brownish pruinescent; covered with uniform black fine setae shorter on tergites dorsally (except noted). Tergite 7 slightly convex, almost devoid of setation, with only 5–6 short posteromarginal setae medially and some setulae laterally. Sternite 7 with similar structure and setation to sternite 6. Segment 8 with tergite and sternite separated. Tergite 8 narrow, somewhat upturned posteriorly, slightly narrowly concave posteromedially; with cluster of several long setae near posterior margin laterally. Sternite 8 large, somewhat convex on posterior part ventrally, weaker sclerotized along midline (especially posteriorly); with numerous long setae along posterior margin, otherwise bare.

Terminalia ( Figs 63–65 ) brownish. Cerci separated from each other and from epandrium, not extended anteriorly beyond tergite 8; mostly grey pruinescent, covered with dark mostly fine setulae, spinule-like setulae on inner face subapically; cercus slightly shorter than epandrium, subrectangular and truncate at apex (lateral view), with notch forming small projection slightly beyond middle dorsally; without pair of subepandrial lobes beneath. Epandrium subtriangular, mostly grey pruinescent, subshiny anteriorly, with numerous long black setae along lower margin. Hypandrium small, subtriangular (ventral view), narrowly sclerotized along margin; bare. Phallus ( Fig. 65 ) well exposed; mostly slender, evenly expanded on basal part, gently sinuate near middle, short apical part extended beyond cerci. Ejaculatory apodeme not extended beyond basal curvature of phallus, with broad lateral wings and narrow vertical wing.

Female. Similar to male, except frons broad, with marginal setulae; eye ommatidia equally small; ocellar tubercle and occiput with shorter and stronger setae. Thorax with shorter setation; mesonotum with somewhat sparser and more differentiated setae, 3–4 npl, 6–8 sctl. Legs without pennate setae, shorter setose; mid femur with dense uniformly long posteroventral setae, mid tibia without av and pv spine-like setae; hind femur less distinctly narrowed on basal part, with longer av setae on basal part, dense long posteroventral setae; hind tibia and basitarsus only slightly expanded (latter as broad as hind tibia at apex), with rather short setae dorsally and ventrally (nearly as long as hind tibia or basitarsus width); tarsomeres 2–4 rather slender, with short setae. Wing membrane darker near wing base (about level of cells br and bm); basal costa seta usually distinct, short. Abdomen densely light grey pruinescent; cercus long slender, with dark setulae.

Distribution. Holarctic; in Eurasia R. sublongiseta sp. nov. is recorded only from Wrangel Island; in North America this species is known only from Yukon.

Etymology. The specific name refers to the similarity of the new species to R. longiseta Saigusa, 1964 .

Remarks. The new species belongs to the R. hirtula group ( Saigusa 1964; Sinclair et al. 2019). In the structure and setation of the male hind leg, R. sublongiseta sp. nov. resembles R. longiseta known from the alpine region of Hokkaido, Japan ( Saigusa 1964). However, the new species differs from R. longiseta by the more extensively setose hind tibia (with long setae only dorsally in R. longiseta ), simple abdominal tergite 8 (with pair of short spatulate projections in R. longiseta ), brownish pruinescent abdomen (ash grey in R. longiseta ) and darker wing base of the female.

Habitat. On Wrangel Island this species was collected mostly in the colder regions (Neozhidannaya River and some coastal areas), where it was captured in various dry biotopes. Apparently, the species is characterized by sharp interseasonal fluctuations in numbers, as evidenced by both Gorodkov’s data (who collected it only in 1966) and ours (on the Neozhidannaya River this species was numerous in 2016, but was not recorded in 2019).

Figures

FIGURES 62–65. Rhamphomyia sublongiseta sp. nov., male. 62. habitus, holotype, lateral view; 63. postabdomen, lateral view; 64. terminalia; 65. phallus, lateral view.Abbreviations: cerc—cercus; ej apod—ejaculatory apodeme; epand—epandrium; hypd—hypandrium; ph—phallus.