Gimnomera aquilonia, Chagnon & Sinclair, 2020

Chagnon, Marie-Eve & Sinclair, Bradley J., 2020, Revision of the Nearctic species of Gimnomera Rondani (Diptera: Scathophagidae) with morphological phylogeny and DNA barcodes, Zootaxa 4853 (3), pp. 369-403 : 373-374

Gimnomera aquilonia sp. nov.

( Figs 1, 2 , 23 , 31 ) urn:lsid:zoobank.org:act:FB11E419-95BA-4C3C-A1F2-AB9BFA234276

Diagnosis. This Nearctic species is characterized by having 3–5 frontal setae and the male terminalia with a cupshaped cercus. Gimnomera aquilonia is similar in appearance to the Nearctic species G. subvittata , G. cuneiventris and G. tibialis because of their similar body colouring, but the cercus of the latter three species is triangular with protrusions. The pregonite of G. subvittata is branched unlike G. aquilonia which has a row of setae on the expanded, unbranched pregonite, while G. cuneiventris and G. tibialis have a teardrop-shaped pregonite with 2–3 setae. The dark coloured males of G. incisurata are also similar in appearance to G. aquilonia . However, this latter species has one postpronotal seta compared to two in G. incisurata .

Description. Male. Body primarily brown to black; pleura dark brown; scutum black. Head with face black and gena black, sometimes with yellow in genal groove; genal width about 1⁄3 eye height; postgena black. Frontal vitta yellow transitioning to black towards ocellar triangle; fronto-orbital plate black sometimes yellowish anteriorly; parafacial black or yellow. Fronto-orbital plate with 3–5 inclinate frontal setae and laterally 1 row of proclinate pale frontal setulae, 1 proclinate and 2 lateroclinate orbital setae, 1 pair of lateroclinate ocellar setae, 1 pair of short divergent postocellar setae, 1 pair of long inclinate inner vertical setae and 1 pair of lateroclinate outer vertical setae. Gena with 2 short supravibrissal setae not equal in size to vibrissa, 1 strong vibrissa, 4–7 variably lengthened subvibrissal setae, 1–3 subequal to vibrissa. Antenna with postpedicel black, about twice as long as pedicel; scape and pedicel black or yellow, 1 long black seta on pedicel; arista black and micropubescent. Palpus pale yellow with short black setae apically as well as long pale setulae on dorsal side. Thorax with long scutal setae usually brown to black, setulae pale; acrostichal setulae biserial, finer than dorsocentrals; 2 presutural (anterior seta short) and 3–4 postsutural dorsocentral setae; 1 posterior postpronotal seta and 8–13 short, stout erect postpronotal setae on anterior portion of postpronotum and scutum, anterior setae variable in thickness; 1 presutural intra-alar seta, 2 notopleural setae, 2 postsutural supra-alar setae, 2 postalar setae. Pleura with 1 proepisternal seta; 1 proepimeral seta; 2 black posterior anepisternal setae and 5–7 pale setulae of variable thickness; 1 posterodorsal katepisternal seta; dorsal 2⁄3 of anepisternum, anepimeron and katepisternum with long pale setulae. Wing (length 2.6–3.1 mm) clear, lightly infuscate; R 1 setose on apical 1⁄4 above, between 5–7 setulae; CuA+CuP ending just short of wing margin. Halter white to brown. Legs entirely brown, occasionally pale; fore, mid and hind tibiae lighter brown than other parts of leg; legs clothed in pale setulae. Fore femur with 1 preapical dorsal seta and 1 posterodorsal seta on apical 1⁄4. Mid femur with 1 preapical posterodorsal seta. Mid tibia with 1 preapical dorsal seta; 1 preapical anterior seta and 1 preapical anteroventral seta. Hind femur with 1 posterodorsal seta, not preapical; 1 proximal posterior seta. Hind tibia with 2 dorsal setae on apical 1⁄4; 1 preapical posterodorsal seta; 1 preapical anterodorsal seta. Tarsi with short, white ventral pile. Abdominal tergites brown/black, shiny and covered in long pale setulae. Abdominal sternites also brown/black. Sternite 5 with 2 small bulbous lobes, outer margin with short stiff setae. Terminalia ( Figs 1, 2 ) with epandrium brown/black; surstylus dark yellow to brown; cercus brown/black; hypandrium brown. Surstylus robust and short, subequal in length to cercus; trough-shaped with indent facing cercus. Cercus rectangular cup-shaped in posterior view; ventral end fused to form cups; posterior fold of cups with setulae on outer surface; cercus wider than surstylus. Pregonite dorsal end broad and ventral end tapered into point; anterior end rounded posteriorly; posterior end with sharp diagonal slant meeting at most ventral point; diagonal slant with many undefined setulae; 1 long black seta at ventral tip of pregonite. Postgonite narrower than pregonite, subequal in length; apical end curved anteriorly.

Female. Similar to male; intersegmental membrane between 7 and 8 clothed with short pale spines; tergite and sternite 8 not fused, both prolonged posteriorly and closely approximated ( Fig. 23 ).

Type material. HOLOTYPE ♂, labelled: “CAN [Canada]: NU [Nunavut]: Cambridge Bay/ 69.12225°, - 105.42191°/ Repl.2 wet, pan traps/ 7–11.vii.2011, NBP field party”; “ HOLOTYPE / Gimnomera / aquilonia / Chagnon & Sinclair [red label]” ( LEM). PARATYPES: CANADA. Northwest Territories: Bailey Pt., Melville Island [74°58′38.3′′N 115°40′04.8′′W], 21.vii.1965, J.E.H. Martin (1♂, CNC). Nunavut: Cambridge Bay, 69°7′20.1′′N 105°25′18.876′′W, Repl.2 wet, sweep, 7.vii.2011, NBP field party (2♀, LEM); same data except, 69°7′20.1′′N 105°25′18.876′′W, Repl.1 wet, Malaise, 7–11.vii.2011 (6♂, LEM); same data except, 69°7′20.1′′N 105°25′18.876′′W, Repl.2 wet, pan traps, 11–15.vii.2011 (2♂, barcoded, LEM); same data except, 69°7′25.176′′N 105°25′31.116′′W, Repl.3 wet, pan traps, 7–11.vii.2011 (1♂, LEM); same data except, 69°7′25.176′′N 105°25′31.116′′W, Repl.3 wet, sweep, 13.vii.2011 (1♂, LEM); same data except, 69°7′25.176′′N 105°25′31.116′′W, Repl.3 wet, Malaise, 15– 19.vii.2011 (2♀, LEM); same data except, 69°7′18.372′′N 105°25′0.768′′W, Repl.2 wet, pan traps, 7–11.vii.2011 (6♂, LEM); same data except, 69°7′18.372′′N 105°25′0.768′′W, Repl.1 wet, Malaise, 7–11.vii.2011 (2♀, 1♂, barcoded, LEM); same data except, 69°7′18.372′′N 105°25′0.768′′W, Repl.2 wet, Malaise, 11–15.vii.2011 (3♀, LEM); same data except, 69°7′18.372′′N 105°25′0.768′′W, Repl.1 wet, pan traps, 11–15.vii.2011 (1♀, LEM); same data except, 69°7′18.372′′N 105°25′0.768′′W, Repl.2 wet, pan traps, 11–15.vii.2011 (1♀, LEM); same data except, 69°7′17.652′′N 105°25′52.464′′W, Repl.3 mesic, Malaise, 15–19.vii.2011 (1♀, LEM); Chesterfield [63°20′52.1′′N 90°44′12.0′′W], 1.vii.1950, J. R. Vockeroth (1♂, CNC); Kugluktuk, 67°50′3.372′′N 115°12′32.22′′W, Repl.3 wet, Malaise, 29.vi.–2.vii. 2011, NBP field party (1♂, LEM). Ontario: Petawawa [45°53′49.6′′N 77°17′02.6′′W], 28.v.1959, J. R. Vockeroth (1♀, CNC). Yukon: North Fork Crossing, 43, Peel Plt. Rd [64°27′N 138°17′W], 3500 ft, 3.vii.1962, P.J. Skitsko (1♀, CNC); North Fork Pass, Ogilvie Mts [64°22′37.5′′N 137°17′32.8′′W], 4300 ft, 19.vi.1962, R.E. Leech (1♀, CNC); same data except, 4100 ft, 20.vi.1962 (1♀, CNC). USA. Michigan: Midland Co. [43°36′55.2′′N 84°15′32.9′′W], 21.iv.1941, R. R. Dreisbach (1♂, USNM).

Distribution. This species is found in the Cordillera ecozone and the arctic ecozone, with southern populations in Ontario and Michigan ( Fig. 31 ).

Etymology. The species name is derived from the Latin aquilonius (facing north, northern, northerly), in reference to its distribution primarily in northern Canada.

Remarks. The two southern specimens are characterized by pale scutal setae and yellowish legs compared to the dark northern specimens.

Figures

FIGURES 1–4. Gimnomera male terminalia, posterior and lateral views. 1–2. G. aquilonia sp. nov.; 3–4. G. cerea (Coquillett). Abbreviations: cerc—cercus; epand—epandrium; hypd—hypandrium; pregt—pregonite; sur—surstylus.

FIGURES 23–25. Female abdomen of Gimnomera species. 23. G. aquilonia sp. nov.; 24. G. tibialis (Malloch); 25. G. vockerothi sp. nov. Abbreviations: hyprt—hypoproct; spmth—spermathecae; st—sternite.

FIGURES 31–32. Known distribution of Gimnomera. 31. G. aquilonia sp. nov.; 32. G. cerea (Coquillett).