Gimnomera vockerothi, 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 : 392-394

Gimnomera vockerothi sp. nov.

( Figs 15, 16 , 20–22 , 25 , 30 , 38 )

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Diagnosis. This Nearctic species is characterized by the colour patterns on the occiput and scutellum, the rectangular male cercus with flap-like apical projection and unique female terminalia. The female terminalia in G. vockerothi have the cercus and epiproct positioned apically, whereas the cercus and epiproct are dorsal in all other female Gimnomera . Females of G. vockerothi also lack the stout spines present in other species of Gimnomera . Other Nearctic species that are similar to G. vockerothi in colouration are G. cerea , G. incisurata and G. terrywheeleri , but the male cercus is triangular in G. cerea and G. incisurata or rectangular with lateral projection in G. terrywheeleri .

Description. Male. Body: Primarily yellow or brown, sometimes darker; pleura yellow or brown; scutum yellow or brown, with dark brown stripe following acrostichal setae visible in pale specimens; entire body glossy. Setae on head yellow. Head with face and gena yellow; genal width 1⁄2 eye height; postgena yellow; postcranium brown. Frontal vitta yellow transitioning to brown towards ocellar triangle; fronto-orbital plate yellow transitioning to black towards ocellar triangle; parafacial yellow. Fronto-orbital plate with 4 inclinate frontal setae, 2 proclinate, 1 lateroclinate orbital setae, 1 pair of lateroclinate ocellar setae, 1 pair of short divergent postocellar setae, 1 pair of inclinate paravertical setae, 1 long inclinate inner vertical seta and 1 lateroclinate outer vertical seta about half length of inner vertical. Gena with 1 strong vibrissa and 6–8 variably lengthened subvibrissal setae. Antenna with postpedicel black, about twice as long as pedicel; scape and pedicel yellow/brown lighter in colour than postpedicel, pedicel with 1 long and many stout pale setae along ptilinal fissure; arista black and pubescent. Palpus yellow, clothed in pale setulae. Thorax with scutal setae yellow; acrostichal setae biserial, finer than dorsocentrals; 2 presutural and 4 postsutural dorsocentral setae; 1 posterior postpronotal seta and two rows of 6–7 light coloured setulae, fine and soft looking on anterior margin of postpronotum and scutum; 1 presutural intra-alar seta, 2 notopleural setae, 0 postsutural intra-alar setae, 2 postsutural supra-alar setae, 2 postalar setae. Pleura with 1 yellow proepisternal seta; 1–2 yellow proepimeral setae; 2 yellow posterior anepisternal setae and several long yellow anepisternal setulae; 1 yellow dorsal posterior katepisternal seta; anterior half of anepisternum bare; anepimeron bare; katepisternum with setulae ventrally. Wing (length 3.5–4.0 mm) clear, lightly infuscate; R 1 with single row of 13–15 setulae on apical 1⁄4 above; CuA+CuP reaching wing margin. Halter white/yellow. Legs entirely yellow. Fore femur with white ventral pile; 2 posterodorsal setae on apical 1⁄4. Fore tibia with 1 preapical dorsal; 1 preapical anterior; 1 preapical posterodorsal; 1 mid dorsal seta. Mid femur with white ventral pile; 1 posterior seta on apical 1⁄4. Mid tibia with 1 preapical posterior; 1 preapical posteroventral; 1 preapical ventral seta. Hind femur with 2 anterodorsal setae on apical 1⁄4; 1 preapical dorsal. Hind tibia with 1 preapical posterodorsal; 1 preapical dorsal; 1 preapical anterodorsal; 1 mid and 1 basal posterodorsal; 1 dorsal on basal 1⁄4; 1 mid anterodorsal seta. Tarsi with short, white ventral pile. Abdominal tergites yellow or brown clothed in pale setulae. Abdominal sternites also yellow or brown. Sternite 5 with 2 broad triangular-shaped lobes, widely spaced from one another, covered in thin setulae ( Fig. 30 ). Terminalia ( Figs 15, 16 ) with epandrium yellow; surstylus yellow; cercus yellow; hypandrium yellow. Surstylus extended beyond cercus, trough-shaped with indents facing cercus. Cercus fused apically with small depression separating ventral lobes; black sclerotized portion along edge of membrane covering anus, extending to where cercus and epandrium meet. Pregonite large with dorsal end broad and ventral end narrower and tapered into rounded point; anterior end with curved diagonal slant and posterior end with rounded point meeting at most ventral point; diagonal slant with many undefined setulae. Postgonite posterior to pregonite, narrower; apical end curved anteriorly.

Female. Similar to male ( Fig. 20 ), except occiput patterned ( Fig. 21 ); frontal vitta completely yellow even toward ocellar triangle; fronto-orbital plate completely yellow even toward ocellar triangle. Scutellum with coloured markings, brown on margins and yellow in middle ( Fig. 22 ). Abdominal tergites with black stripe on posterior end of tergite. Terminalia ( Fig. 25 ) somewhat compressed laterally, not strongly sclerotized. Tergite and sternite 8 separate, thinly sclerotized, divided medially by membranous dorsal and ventral imarginations; setae unmodified, without spines. Cercus, epiproct and hypoproct all jutting out from most apical point of terminalia.

Type material. HOLOTYPE ♂, labelled: “ 17 mi. W.of/ Hedley, B.C. [49°21′26.3′′N 120°04′37.1′′W]/ 31.v.1959 / R. E. Leech ”; “ HOLOTYPE / Gimnomera / vockerothi / Chagnon & Sinclair [red label] [dissected]” ( CNC) . PARATYPES: CANADA. Alberta: 20 mi W Calgary [51°02′44.2′′N 114°04′51.8′′W], 25.vi.1962, K.C. Herrmaan (1♀, CNC) ; Elkwater [49°39′43.5′′N 110°16′50.8′′W], 31.v.1952, L.A. Konotopetz (1♀, CNC) ; Elkwater [49°39′43.5′′N 110°16′50.8′′W], 13.vii.1952, A. R. Brooks (1♀, CNC) ; Elkwater [49°39′43.5′′N 110°16′50.8′′W], 9.vi.1956, E.E. Sterns (1♀, CNC) ; Elkwater [49°39′43.5′′N 110°16′50.8′′W], 10.vi.1956, O. Peck (1♀, CNC) ; Kananaskis, For. Exp. Stn. Seebe [51°01′37.73′′N 115°02′08.38′′W], Malaise trap, 21.vi.1968, H.J. Teskey (1♀, 1♂, CNC) . British Columbia: Hixon [53°24′58′′N 122°34′56′′W], 7.vi.1966, E.D.A. Dyer (1♀, CNC) ; same data except, 21.vi.1966 (1♀, CNC) ; same data except, 6.vii.1966 (1♀, CNC) . Yukon: Dempster Hwy near North Fork Pass , 64°35′50.496′′N 138°18′36.324′′W, 1180 m, Repl. 2 wet, Malaise, 24–27.vi.2011, NBP field party (1♂, barcoded, LEM) . USA. Alaska: Eagle River [61°19′45.55″N 149°34′04.98″W], 60 m, NE Anchorage, 18.vi.1994, T. Saigusa (1♂, KUMF) ; Nome area, mi 17 Kougarok Rd , 64.71°N 165.30°W, Malaise trap, 21.vi.2005, J. & R. Skevington (1♀, CNC) . Colorado: Caribou , 10000 ft [39°58′50′′N 105°34′40′′W], 18.vi.1961, C.H. Mann (1♀, CNC) ; Clear Ck Co., West Chicago Ck , 9800 ft [39°40′44.27′′N 105°39′26.62′′W], 11.viii.1961, B.H. Poole (1♀, CNC) .

Distribution. This species is found in western Canada and Alaska, ranging primarily along the western Cordillera south to Colorado ( Fig. 38 ).

Etymology. This species is named after the late J.R. Vockeroth, formerly of the CNC, who worked extensively on the family Scathophagidae , including Gimnomera .

Remarks. The male and female terminalia and sternite 5 of G. vockerothi is rather similar to G. albipila (see Ozerov 2019, figs 9, 28, 29; Engelmark & Haarto 2019, fig. 9a). The latter species was assigned to a new subgenus by Engelmark & Haarto (2019), but a thorough phylogenetic analysis of all Holarctic species should be conducted to test this proposal.

Figures

FIGURES 13–16. Gimnomera male terminalia, posterior and lateral views. 13–14. G. tibialis (Malloch); 15–16. G. vockerothi sp. nov. Abbreviations: ph—phallus; pregt—pregonite.

FIGURES 17–20. Male and female Gimnomera, lateral views. 17. G. subvittata (Malloch), male; 18. Female of possible ninth species of Nearctic Gimnomera (Gimnomera sp. A); 19. G. tibialis (Malloch), female; 20. G. vockerothi sp. nov., female.

FIGURES 21–22. Gimnomera vockerothi sp. nov., female. 21. Colour patterns on the occiput; 22. Colour pattern on scutellum.

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 26–30. Morphological features of Gimnomera. 26–27. View of anterior margin of postpronotum with dark spine-like setae or with light coloured setulae: 26. G. cerea (Coquillett); 27. G. terrywheeleri sp. nov.; 28. G. tibialis (Malloch), vein R1 with row of setulae; 29–30. Male sternite 5: 29. G. subvittata (Malloch); 30. G. vockerothi sp. nov..

FIGURES 37–38. Known distribution of Gimnomera. 37. G. tibialis (Malloch); 38. G. vockerothi sp. nov..