Anthomyza orthogibbus, Roháćek & Barber, 2016

Roháćek, Jindřich & Barber, Kevin N., 2016, Nearctic Anthomyzidae: a monograph of Anthomyza and allied genera (Diptera), Acta Entomologica Musei Nationalis Pragae (suppl.) 56, pp. 1-412 : 268-277

Anthomyza orthogibbus sp. nov.

( Figs 384 , 440–455 )

Type material. HOLOTYPE: ♂, “CAN:ON:SSMarie, Sault Coll.Outdoor Lab, 17.vii.2005, KNBarber, sweeps, Carex lacustris in opening 46°32.08'N 84°18.21'W ” and “ HOLOTYPUS ♂ Anthomyza orthogibbus sp. n., J. Roháček & K. N. Barber det. 2013” (red). The specimen is in perfect condition, with well visible exposed genitalia (see Fig. 384 ) ( CNCI, intact). PARATYPES: CANADA: MANITOBA: ~ 14 km SW Falcon Lake, jct.Hwy#1 & Rd.86E, 49°38.24'N 95°29.89'W, sweeps, graminoids, mostly Carex spp., 30.vii.2008, 2 ♂♂ 2 ♀♀, 29.vii.2011, 3 ♂♂ 3 ♀♀ (2 ♀♀ genit. prep.), K. N. Barber leg. ( CNCI). ONTARIO: Batchawana P. Pk., 46°56.67'N 84°33.30'W, sweeps, mostly Carex spp. in wet trench under mixed canopy, 19.vii.2014, 3 ♂♂, K. N. Barber leg. ( DEBU 01503961–63); Beverly Swamp, 7 km SSE Guelph, swept/eclector, forest & swamp, (Universität Bielefeld, X 978), 18.viii.1994, 1 ♂ 1 ♀, M. v. Tschirnhaus leg. ( ZSMC, in ethanol); ~ 40 km NE Chapleau, 47°59.76'N 82°55.04'W, wet roadside sweeps, mostly Carex utriculata , 23.vi.2013, 1 ♂; Echo Bay, Echo Bay Marsh, 46°29.71'N 84°04.04'W, nr. lookout, sweeps, mostly Carex incl. C. utriculata , 24.vi.2012, 1 ♂; same locality but 46°29.66'N 84°04.12'W, near lookout, sweeps, mostly Carex utriculata , 15.vi.2013, 3 ♂♂ 3 ♀♀, 29.vi.2013, 3 ♂♂ 3 ♀♀, sweeps, mixed graminoids incl. Carex utriculata , 21.vii.2013, 8 ♂♂ 4 ♀♀; same locality but 46°29.71'N 84°04.04'W, sweeps, mostly Equisetum ssuviatile , Typha latifolia , 12.vi.2007, 1 ♀, sweeps, mostly Equisetum ssuviatile , Schoenoplectus acutus , 12.vi.2007, 2 ♂♂ 3 ♀♀, 18.vi.2007, 2 ♀♀, sweeps, mostly Equisetum ssuviatile , 18.vi.2007, 2 ♀♀, 12.vii.2008, 1 ♀, all K. N. Barber leg. (all CNCI); Echo Bay, Echo Bay Marsh, 46°29.71'N 84°04.04'W, ex. Equisetum ssuviatile ?, moist ground cover including E. ssuviatile , 10.v.2008, [reared at] 20°C, L:D 16:8, emerged: 3.vi.2008, 1 ♀, 5.vi.2008, 1 ♀; Echo Bay, Echo Bay Marsh, 46°29.71'N 84°04.04'W, ex. Equisetum ssuviatile , dry stalks on surface, 10.v.2008, [reared at] 20°C, L:D 16:8, emerged: 27.v.2008, 1 ♂, 28.v.2008, 1 ♂, 2.vi.2008, 1 ♂; Echo Bay, Echo Bay Marsh, 46°29.71'N 84°04.04'W, ex. Equisetum ssuviatile , dry stalks on surface, 17.v.2008, 20°C, L:D 16:8, emerged: 1.vi.2008, 1 ♂, 2.vi.2008, 2 ♂♂, 5.vi.2008, 2 ♂♂ 1 ♀, 7.vi.2008, 1 ♂ 1 ♀, 12.vi.2008, 2 ♀♀; Echo Bay, Echo Bay Marsh, 46°29.71'N 84°04.04'W, ex. Equisetum ssuviatile , dry stalks on surface, 4.iv.2009, [reared at] 6°C, L:D 0:24, instar 3 dissected 10.iv.2009, 20°C, L:D 16:8, [each with empty puparium in gelatin capsule], puparium: 25.iv.2009, emerged: 9.v.2009, 1 ♂, puparium: 30.iv.2009, emerged: 15.v.2009, 1 ♂, puparium: 1.v.2009, emerged: 16.v.2009, 1 ♀, puparium: 6.v.2009, emerged: 20.v.2009, 1 ♂, puparium: 9.v.2009, emerged: 24.v.2009, 1 ♀, puparium: 11.v.2009, emerged: 25.v.2009, 1 ♂, puparium: 14.v.2009, emerged: 29.v.2009, 1 ♂, puparium: 18.v.2009, emerged: 31.v.–1.vi.2009, 1 ♀, puparium: 19.v.2009, emerged: 2.vi.2009, 1 ♀, all K. N. Barber leg. (all CNCI); Elliot Lake, 46°22.23'N 82°36.49'W, sweeps, mixed graminoids incl. Carex utriculata , 29.vi.2013, 4 ♂♂ 7 ♀♀ (2 ♀♀ genit. prep.) ( CNCI); ~ 14.5 km SSE Elliot Lake, ~ 3.7 km NNE jct Hwys 17&108, 46°14.71'N 82°33.53'W, sweeps, mostly Carex utriculata , 29.vi.2013, 23 ♂♂ 14 ♀♀ ( USNM 5 ♂♂ 5 ♀♀, CNCI 18 ♂♂ 9 ♀♀, 2 ♀♀ genit. prep.), all K. N. Barber leg.; Goulais River, Sand Bay, 46°44.81'N 84°32.68'W, sweeping Juncus and Carex at margins of fen pools, 10. vii.2010, 1 ♂, J. Roháček leg.( SMOC); Lake Superior P. Pk., Hwy 17 near jct.Agawa Rock, 47°22.31'N 84°41.23'W, sweeps, mostly Carex utriculata , 30.vi.2013, 1 ♀ ( DEBU 01503844, genit. prep.), 12.vii.2014, 2 ♂♂ 3 ♀♀ ( DEBU 01503954–58), K. N. Barber leg.; Manitoulin I[sland], nr. Evansville, Campbell Bay, 45°49'32"N 82°33'14"W, sweeping lake shore graminoid vegetation, 2.vii.2010, 1 ♀, J. Roháček leg. ( SMOC, genit. prep.); Manitoulin Is., ~ 2.2 km N Cold Springs, Perch Ck at Hwy 540, 45°53.1'N 82°06.2'W, sweeps/pooter, Calamagrostis canadensis , 4.vii.1999, 1 ♂ 2 ♀♀ (1 ♀ genit. prep.); same locality but 45°53.2'N 82°06.3'W, sweeps, various grasses / sedges in noodplain, 5.vii.1998, 1 ♀ (genit.prep.), all K.N. Barber leg.(all CNCI); Pancake Bay P.Pk., 46°58.11'N 84°42.72'W, sweeps from boardwalk, mostly emergent sedges / Equisetum , 2.viii.2004, 2 ♂♂ 1 ♀ ( DEBU 01500873–75), 7. viii.2004, 3 ♂♂ 2 ♀♀ ( DEBU 01501092–96), 3.ix.2004, 1 ♂ ( DEBU 01501324), 4.ix.2004, 1 ♂ ( DEBU 01501431), 27.vi.2005, 4 ♂♂ 2 ♀♀ ( DEBU 01501614–19), 7.vii.2007, 1 ♀ ( DEBU 01501896), 29.v.2010, 1 ♂ ( DEBU 01502435); same locality but 46°58.10'N 84°42.71'W, sweeps, mostly Carex nr. wetland boardwalk, 24.vii.2004, 1 ♂ 3 ♀♀ ( DEBU 01500726–29), 2.viii.2004, 1 ♀ ( DEBU 01500903), sweeps, mostly Carex utriculata in fen near boardwalk, 19.vii.2014, 6 ♂♂ 3 ♀♀ ( DEBU 01503979–87, 1 ♀ genit. prep.); same locality but 46°58.06'N 84°42.69'W, sweeps, mostly Carex utriculata in fen, 19.vii.2014, 6 ♂♂ 6 ♀♀ ( DEBU 01503989–4000), all K. N. Barber leg.; ~ 2 km SW Richmond, along railway 2.9 km NE Kettles Rd., 45°08.54'N 75°51.09'W, sweeps, Equisetum ssuviatile , Typha , Carex , Impatiens , ditch, 25.vii.2007, 1 ♂; ~ 4 km SW Richmond, Jct. Munster Rd./Kettles Rd., 45°06.83'N 75°52.76'W, sweeps, sedges, Equisetum ssuviatile , nooded ditch/fen, 23.vii.2007, 1 ♂ 2 ♀♀, all K. N. Barber leg. (all CNCI); S[ault] S[te.] Marie, S. of Algoma U[niversity] College, 46°29.9'N 84°17.2'W, sweeps, Carex aquatilis , 12.vii.1997, 1 ♂ (genit. prep.), 22.vi.1998, 1 ♂ (genit prep.), 9.vi.2001, 2 ♀♀, 10.vi.2001, 1 ♂, 28.vi.2002, 2 ♂♂ 3 ♀♀ (1 ♀ genit. prep.), 29.vi.2002, 2 ♂♂ 3 ♀♀ (2 ♀♀ genit. prep.) ( CNCI), 1.vii.2002, 1 ♂ 1 ♀ ( CASC), 5.vii.2002, 2 ♂♂ 1♀ (1 ♀ genit.prep.), 9.vii.2002, 1 ♂ 5 ♀♀ (3 ♀♀ genit.prep.) ( CNCI), 12.vii.2002, 1 ♀ ( CASC), 31.vii.2002, 2 ♀♀ (1 ♀ genit. prep.), 18.vi.2005, 2 ♂♂ ( CNCI), sweeps, mostly Carex aquatilis , 12.vi.2001, 2 ♂♂, 13.vi.2001, 1 ♀, 14.vi.2001, 1 ♂ 2 ♀♀ ( LACM), 14–17.vi.2001, 2 ♂♂ 7 ♀♀ (1 ♀ genit. prep.), 21–22.vi.2001, 3 ♀♀, 22. vi.2001, 1 ♂, 25.vi.2001, 2 ♂♂ 10 ♀♀ (1 ♀ genit. prep.), 28–30.vi.2001, 5 ♀♀ (1 ♀ genit. prep.) ( CNCI), 15. vii.2001, 1 ♀, 17.vii.2001, 4 ♂♂ 3 ♀♀ ( AMNH), 18.vii.2001, 5 ♀♀ (1 ♀ genit. prep.), 2.viii.2002, 1 ♀, 4.viii.2002, 1 ♂ 1 ♀ (1 ♀ genit. prep.), sweeps, Carex lacustris , 12.vii.1997, 1 ♀, sweeps, mostly Calamagrostis canadensis , 29.vii.2001, 1 ♀, sweeps/pooter, mostly Calamagrostis canadensis , 12.vii.2002, 1 ♂, sweeps, graminoids mostly Carex aquatilis , 11.vi.1997, 2 ♀♀ ( CNCI); same locality but 46°29.88'N 84°17.19'W, sweeps, Carex aquatilis , 1.vii.2003, 2 ♂♂ 1 ♀ ( CASC), 18.vi.2005, 1 ♂ 1 ♀, sweeps, mostly Carex aquatilis , 18.vii.2004, 2 ♀♀, sweeps, Phalaris arundinacea , 18.vi.2005, 1 ♂ ( CNCI), all K. N. Barber leg.; S[ault] S[te.] Marie, S. of Algoma University, 46°29.88'N 84°17.19'W, sweeps, mostly Carex spp., Scirpus cyperinus , 5.vii.2008, 4 ♂♂ 1 ♀; S[ault] S[te.] Marie, Birchwood Pk., mixed forest, 28.vi.1986, 1 ♀; S[ault] S[te.] Marie, Finn Hill, 46°31.48'N 84°17.36'W, sweeps, mostly Scirpus microcarpus , 18.vi.2005, 8 ♂♂ 1 ♀, 14.viii.2005, 1 ♂, 25.viii.2005, 1 ♀, 8.vii.2006, 1 ♀, all K. N. Barber leg. (all CNCI); Sault Ste. Marie, Finn Hill, 46°31.48'N 84°17.36'W, sweeping graminoid vegetation, 7. vii.2010, 5 ♂♂ 7 ♀♀ (2 ♂♂ 7 ♀♀ genit. prep.), 12.vii.2010, 2 ♂♂, J. Roháček leg. ( SMOC); S[ault] S[te.] Marie, Finn Hill, 46°31.63'N 84°17.29'W, sweeps, Scirpus microcarpus , 19.vii.2004, 1 ♂, 27.vi.2007, 2 ♂♂, 13.vii.2007, 1 ♂ 2 ♀♀, 6.vii.2008, 1 ♂; same locality but 46°31.63'N 84°17.33'W, sweeps, Carex stipata stipata , 19.vii.2004, 1 ♀, 26.vi.2007, 1 ♂, all K. N. Barber leg. (all CNCI); Sault Ste. Marie, Finn Hill, 46°31.63'N 84°17.33'W, sweeping boggy meadows, mostly Carex stipata stipata , 12.vii.2010, 1 ♂, J. Roháček leg. ( SMOC); S[ault] S[te.] Marie, Kinsmen Pk., 46°35.7'N 84°16.7'W, sweeps, mostly Carex , 11.viii.2002, 1 ♀ ( CNCI); S[ault] S[te.] Marie, Sault Coll[ege] Outdoor Lab, 46°32.08'N 84°18.21'W, sweeps, Carex lacustris in opening, 17.vii.2005, 16 ♂♂ 20 ♀♀ (1 ♀ genit. prep.) ( CNCI), 2.viii.2005, 24 ♂♂ 22 ♀♀ ( USNM 5 ♂♂ 5 ♀♀, CNCI 19 ♂♂ 17 ♀♀, 3 ♀♀ genit. prep.), 24.viii.2005, 1 ♂ 1 ♀, sweeps, Carex lacustris , 8.vii.2006, 6 ♂♂ 5 ♀♀ (1 ♀ genit. prep.) ( CNCI), 28.viii.2006, 5 ♂♂ 6 ♀♀ ( SMOC), 16.ix.2006, 2 ♂♂, 17.vii.2007, 7 ♂♂ 16 ♀♀, 12.vii.2008, 2 ♂♂ 2 ♀♀ (1 ♀ genit. prep.), sweeps, Carex gynandra , opening edge, 2.viii.2005, 2 ♀♀ ( CNCI); ~ 5 km SE Searchmont, km6.2 Ranger Lk. Rd., 46°45.52'N 83°59.51'W, sweeps, sedges at beaver dam outnow, 23.vi.2007, 1 ♂ ( CNCI), all K. N. Barber leg.; Walpole Is., 13.vii.1980, 1 ♀ (genit. prep.), K. N. Barber leg. ( DEBU). QUEBEC: Gatineau Park, Champlain Outlook, 21.vii.1986, 1 ♂, R. Danielsson leg. ( MZLU, genit. prep.); La Trappe, 4.vi.1936, 1 ♀, J. Ouellet leg. ( CNCI, genit. prep.); Lac St-Francois Nat.Wildlife Area, NW of Aménag.Therrien, close to Ruisseau Th[errien], 45°00.39'N 74°30.99'W, Carex meadow, sweeping, T1a, 5.vi.1999, 1 ♂ 2 ♀♀ ( LEMQ 0040135, -41, -42), 7.viii.1999, 2 ♂♂ ( LEMQ 0040132, -38), T1b, 5.vi.1999, 2 ♂♂ 5 ♀♀ ( LEMQ 0040136, -37, -40, -41, -44, -48, -49, 1 ♀ genit. prep.), 2.viii.1999, 1 ♂ 1 ♀ ( LEMQ 0040134, -46), 3–11.ix.1999, 1 ♀ ( LEMQ 0040140), T1c, 5.vi.1999, 1 ♂ 2 ♀♀ ( LEMQ 0040133, -45, -47); same locality but 45°02.40'N 74°28.03'W, ex. Carex lacustris , under sheath leaf at 10–15 cm from roots, ( F 2,#157), 19.x.1999, emerged 9.ii.2000, 1 ♀ ( LEMQ 0040151), all F. Beaulieu leg. UNITED STATES OF AMERICA: ILLINOIS: Champaign Co., 25.v.1925, 1 ♀, M. W. Shackleford leg. ( CNCI). MASSACHUSETTS: Sandwich, 22.vi.1924, 1 ♀ (genit. prep.), A. H. Sturtevant leg.; Woods Hole, 6.vi.1913, 1 ♂, [no collector] (both USNM). NEW YORK: Bemus Pt., Chautauqua Lake, swampy woods, 31.v.1963, 1 ♀ (genit. prep.); Chautauqua Co., S. Dayton, marsh area, 1.vi.1963, 1 ♀ (genit. prep.), both W. W. Wirth leg. (both USNM); Roch, 22.vii.1942, 1 ♂, H. Stalker leg. ( AMNH). NORTH CAROLINA: Highlands, 3800', 17.viii.1957, 1 ♂, J. G. Chillcott leg. ( CNCI). OHIO: Portage Co., Kent, 41°09'N 81°30'W, 17.vi.2006, 1 ♀; Portage Co., 4 mi NE of Kent, Battaglia Bog, swept from Carex oligosperma , 15.v.1999, 1 ♂ 3 ♀♀ (3 ♀♀ genit. prep.); Portage Co., 3 mi NE of Kent, Towners Woods Marsh, 1.vi.2005, 1 ♀; Portage Co., NE of Kent, Towners Woods Marsh, swept from Scirpus cyperinus , 8.vi.2005, 2 ♂♂ 3 ♀♀, 16.vi.2005, 1 ♂, 25.vi.2005, 1 ♂, 26.vii.2005, 1 ♂; Portage Co., NE of Kent, Towners Woods Marsh, 41°10'N 81°18'W, swept from Leersia oryzoides (L.) Sw., 14.v.2007, 1 ♀, swept from Scirpus cyperinus , 20.v.2007, 1 ♂ 3 ♀♀; Portage Co., 4.0 mi E of Kent, 41°08'11"N 81°16'44"W, 1.vi.2005, 1 ♂ 1 ♀, all B. A. Foote leg. (all CMNH). VIRGINIA: Chain Bridge, 10.ix.1922, 1 ♂, J. R. Malloch leg. ( USNM).

Other material examined (not included in type series). CANADA: ONTARIO: Echo Bay, Echo Bay Marsh, 46°29.71'N 84°04.04'W, ex. Equisetum ssuviatile , dry stalks on surface, 17.v.2008 ,20°C, L:D 16:8, emerged: 5.vi.2008, 1 ♀, K. N. Barber leg. ( CNCI, shriveled, genit. prep.) ; ~ 14.5 km SSE Elliot Lake, ~ 3.7 km NNE jct Hwys 17&108, 46°14.71'N 82°33.53'W, sweeps, mostly Carex utriculata , 29.vi.2013, 1 ♂, K. N. Barber leg. ( CNCI, head crushed, wing illustration) ; Sault Ste. Marie, Finn Hill , 46°31.48'N 84°17.36'W, sweeping graminoid vegetation, 7.vii.2010, 2 ♂♂, J. Roháček leg. ( SMOC, used for molecular analysis) . QUEBEC: Lac St-Francois Nat. Wildlife Area, NW of Aménag.Therrien, close to Ruisseau Th [errien], 45°00.39'N 74°30.99'W, Carex meadow, sweeping, T1 b, 5.vi.1999, 1 ♀, F. Beaulieu leg. ( LEMQ 0040150 , headless, genit. prep.) .

Description. Male. Total body length 2.26–3.09 mm; colour resembling that of pale form of A. gibbiger , generally yellow ( Fig. 384 ) with variable ochreous to pale brown darkenings on head and thorax (always with brownish dorsal band on pleuron) and more distinctly yellow-and-brown variegated preabdominal terga; no dichroism recognized (dark form absent). Head similar to that in A. gibbiger , distinctly longer than high (thus more elongate than in A. variegata ) and anteriorly angular in pronle with somewhat receding face. Head almost completely yellow, with only ocellar triangle and some marginal darkenings on occiput brownish (see below). Occiput slightly concave, largely yellow but usually with narrow faint darker stripes dorsolaterally and above foramen; medially with two elongate silvery white microtomentose spots meeting above foramen (as in A. variegata ). Frons narrow as in relatives, yellow, usually darker yellow to orange ochreous anteromedially and along orbits, mostly dull; ocellar triangle pale brown to brown; frontal triangle relatively dull yellow but slightly glittering in contrast to entirely opaque and paler yellow adjacent areas. Orbits pale yellow, silvery whitish microtomentose, less distinctly beyond posterior ors. Frontal triangle narrow, reaching midpoint to anterior third of frons. Frontal lunule small, transverse, pale yellow. Face narrow, medially concave or with longitudinal furrow; dull yellow and separated from parafacialia by wide golden orange marginal stripe (as in pale form of A. gibbiger ); parafacialia and gena whitish yellow to white, with silvery white microtomentum; ventral marginal stripe of gena yellow and wider than in most relatives. Postgena and mouthparts yellow to light yellow. Cephalic chaetotaxy generally as in A. variegata , except vte often as long as vti and posterior ors (thus these setae subequal); middle ors sometimes reaching length of posterior ors. Eye ovoid, more elongate than in A. variegata , with longest diameter 1.5–1.6 times as long as shortest. Shortest genal height 0.13–0.15 times as long as shortest eye diameter. Antenna nattened, geniculate, yellow; 1st nagellomere usually darker on outer side than on inner, and with white pilosity distinctly shorter than in A. variegata . Basal segments of arista ochreous yellow to pale yellow and distal seta blackish brown; arista 1.8–1.9 times as long as antenna, relatively shortly pubescent (as in A. gibbiger ), with cilia markedly shorter than those on 1st nagelomere.

Thorax very slightly narrower than head, largely yellow, with rather faint brownish pattern on scutum, and darker band on pleuron. Scutum yellow, usually with darker yellow to pale ochreous brown sublateral bands, sometimes with a pair of medial darker stripes in addition. Humeral and notopleural areas pale yellow; scutellum yellow to dark yellow. Dorsum of thorax somewhat pale ochreous grey microtomentose and relatively dull. Pleural part of thorax more shining than scutum, yellow to pale yellow (ventrally), always with pale brown to brown dorsal band. Postscutellum distinctly darker than postnotum and scutellum, ochreous yellow to ochreous brown. Thoracic chaetotaxy as in A. variegata but prs usually shorter and weaker than hu, sa or pa; the smaller anterior dc about as long as or shorter than anterior npl, and 6–8 dc microsetae in front of anterior dc; 4–5 rows of ac microsetae at suture, only 2 medial rows between dc ending usually at level of posterior dc; apical sc subequal to posterior dc (both longest thoracic setae); no additional small setulae on scutellum, laterobasal short sc situated more dorsally on disc (as in A. gibbiger ); stpl setae and setulae as in A. gibbiger including occasional occurrence of 1 additional setula in front of anterior stpl. Scutellum broader than in A. gibbiger , thus more similar to that of A. variegata . Legs coloured as in A. variegata and other relatives; also pedal chaetotaxies very similar but f 1 with ctenidial spine not longer (often shorter) than maximum width of t 1, thus markedly shorter than in all Nearctic relatives. Wing ( Fig. 440 ) narrow, elongate and coloured as in A. gibbiger . Also venation very similar to that of the latter species, including R 2+3 with apex very slightly upcurving; R 4+5 very slightly bent and parallel, M almost straight, dm cell long, with r-m situated in front of its middle and apical portion of CuA 1 longer than dm-cu. Wing measurements: length 2.24–2.74 mm, width 0.65–0.85 mm, Cs 3: Cs 4 = 1.12–1.38, rm\dm-cu: dm-cu = 2.62–3.69. Haltere dirty yellow with some ochreous to pale brown tinge.

Abdomen ventrally pale yellow, dorsally yellow-and-pale brown variegated ( Fig. 384 ), thus its transverse striping usually less distinct, resembling that of pale forms of dichroic relatives. T1 pale brown with anterior corners light yellow. T2–T5 more or less yellow in anterior half, posteriorly with transverse pale brown band covering half or more of tergum and almost reaching onto posterior corners but lateral margins of terga largely yellow. T1T5 subshining with setae relatively short and sparse compared to A. variegata . T1 and T2 distinctly separate, only laterally fused. T2–T5 transverse, subequal in size. Preabdominal sterna pale yellow, relatively narrow and becoming distinctly wider posteriorly, similar to those of A. gibbiger including chaetotaxies. T6 bare, short, strongly transverse and very pale to unpigmented. S6 and S7 pale yellow, both with nne brownish anterior marginal ledge and each with 1–(usually)2 setae; S8 as long as but distinctly narrower than epandrium, with about anterior third yellow, and posterior two-thirds brownish and more setose.

Genitalia. Epandrium ( Figs 441, 443 ) pale yellow, about as long as, but slightly wider and higher than that of A. gibbiger , densely setose, dorsolaterally with 2 or 3 longer and thicker setae (most dorsomedial one longest); anal nssure rounded triangular but smaller than in A. gibbiger . Cercus rather small and setose as in the latter species. Medandrium (see Fig. 441 ) also as in A. gibbiger or dorsally more narrowed. Gonostylus ( Figs 441, 443, 448 ) distinctly different from that of A. gibbiger , elongate, almost as long as epandrial height, not expanded posteroproximally but gradually tapered towards apex and ending in two (anterior stronger) teeth; outer side of gonostylus covered by micropubescence except for anterior and apical parts; longer setae inserted mainly on inner side, most densely posteroproximally. Hypandrium ( Fig. 444 ) as in A. gibbiger and other relatives. Transandrium ( Figs 442, 445 ) closely resembling that of A. gibbiger , including caudal process having dorsally a hump-shaped projection overgrown by short dark spines, but this projection smaller ( Figs 444 ) and more slender ( Fig. 442 ). Distal part of caudal process almost bare, only (ventral) basal membrane densely shortly spinose. Pregonite ( Fig. 444 ) completely fused to hypandrium, with posterior process reduced and carrying 2 longer setae, anteriorly simple, slightly convex ventrally and with 3 short setae. Postgonite ( Fig. 444 ) pale-pigmented, relatively small, slender and almost straight, distally somewhat tapered and with rather acute apex; its outer side with 1 setula in basal two-nfths plus several sensillae. Basal membrane ( Figs 444, 445 ) covered by a dense group of small, short (shorter than in A. gibbiger ) and nat spines. Aedeagal part of folding apparatus provided besides small dark spine-like tubercles ( Fig. 446 ) also with series of bigger spines (distinctly smaller than in A. gibbiger ) on hyaline striae (visible in Fig. 444 above postgonite). Connecting sclerite as in A. gibbiger , dark, dorsally more sclerotized ( Fig. 446 ) and ventrally provided by a group of short dark but pointed spines. Phallapodeme of the same construction as that of A. gibbiger . Aedeagus ( Fig. 446 ) differing from that of A. gibbiger only as follows. Saccus with more distinct basal sclerite attached to base of nlum but otherwise armed as in A. gibbiger . Filum differing mainly by thicker apex with terminal curved projection short and blunt; also tooth-like spines alongside dorsal surface of terminal part of nlum smaller ( Fig. 447 ). Ejacapodeme (not ngured) reduced, very slender, pale and formed as in A. gibbiger .

Female. Similar to male unless mentioned otherwise. Total body length 2.50–3.57 mm. Antenna with 1st nagellomere darker than in male (resembling that of darker specimens of A. gibbiger ), with ochreous brown area covering most of outer side except for yellow basal and ventral marginal parts; inner side of 1st nagellomere yellow. Darker pattern of thoracic scutum usually paler and less discernible than in males; usually with at least a short, brownish lateral darkening in front of transverse suture, sometimes very distinct and extending beyond suture, but rarely absent. Dorsal dark band on pleural part of thorax usually widened anteriorly to ventral margin of spiracular plate (usually not so in A. gibbiger females). Ctenidial spine on f 1 long and strong, markedly longer than maximum width of t 1, thus similar to those of females of related species. Wing relatively wider than in males. Wing measurements: length 2.54–3.45 mm, width 0.85–1.11 mm, Cs 3: Cs 4 = 1.08–1.53, rm\dm-cu: dm-cu = 2.41–3.68. Preabdominal terga T2–T6 with posterior dark transverse bands usually more distinct and shorter than in males, and usually larger and more distinct than in A. gibbiger females; stripes on T3–T6 may be medially narrowed, with stripe on T6 sometimes narrowly divided. T2–T5 subequal in size but shorter and more transverse than in male, wider than T6. Preabdominal sterna pale yellow, becoming wider posteriorly but (particularly S4 and S5) somewhat narrower than in male. S2 as long as wide, S3 slightly, S4 more, S5 distinctly transverse and trapezoidal. S5 largest and widest, about as wide as postabdominal S6.

Postabdomen ( Figs 450, 451 ) very similar to that of A. gibbiger , moderately long, tapered posteriorly, telescopic, with most sclerites yellow, only T6 and T7+S7 with posterior brown band. T6 simple, large, slightly tapered posteriorly with rounded posterior corners, yellow, with more distinct dark band at posterior margin, with most of setae in posterior half, those at posterior margin longest. S6 slightly transversely suboblong to trapezoidal (thus longer than in A. gibbiger ), pale yellow and nnely densely setose. Tergosternum T7+S7 conical, distinctly shorter dorsally than ventrally, yellow with distinct brown stripe (slightly wider than in A. gibbiger ) at posterodorsal margin ( Fig. 450 ) reaching lateral surface; T7+S7 anteroventrolaterally somewhat expanded as in A. gibbiger to form anteroventral lobes ( Fig. 451 ) though not pouch-like as in A. variegata , largely yellow but often with faint darkening at ventral posterior margin (but not medially); medioventral area ( Figs 450a, 451 ) hardly pronounced in contrast to that of A. gibbiger ( Figs 450a , see ventral arrow, 451); in lateral view the segment is distinctly longer and anteriorly in the middle more angular ( Fig. 450a , see anterior arrow) than in the latter species. Dorsal parts of T7+S7 with short setae at posterior dark margin ( Fig. 450 ) as in A. gibbiger , ventral part (= original S7) most densely setose medially ( Fig. 451 ). 8th segment micropubescent laterally. T8 yellow, narrow and elongate, much longer than wide, posteriorly rounded ( Fig. 450 ), distinctly micropubescent and setose (setae slightly exclinate as in A. gibbiger ) in posterior half; S8 ( Fig. 451 ) markedly wider than T8, medially divided into 2 convex, nnely hirsute and micropubescent sclerites as in relatives. Genital chamber (uterus) long, posteriorly with pale-pigmented internal sclerotization ( Figs 452, 453 ) formed by 3 pairs of crooked, poorly denned and partly fused sclerites (similar to those of A. gibbiger ), and 1 suboval, asymmetrical and bent annular sclerite (somewhat larger than in latter species). Distal membranous part of genital chamber ( Fig. 455 ) with pale and poorly denned ventral plate as in A. gibbiger . Ventral receptacle ( Fig. 455 ) also resembling that of the latter species, with basal broad part shorter and vermicular apex less twisted. Accessory gland as in A. gibbiger (not ngured). Spermathecae (1+1) rounded cylindrical ( Figs 449, 454 ), very similar to those of A. gibbiger but usually more elongate and with terminal invagination deeper. T10 very small ( Fig. 450 ), slightly shorter than broad, with usual posteromedial pair of long setae and reduced micropubescence. S10 longer and wider than T10, rounded pentagonal in ventral view ( Fig. 451 ), nnely setulose and micropubescent. Cercus moderate, slender (basally somewhat wider than in A. gibbiger ), with usual setae, apical and dorsopreapical longest ( Figs 450, 451 ).

Discussion. As stated above, A. orthogibbus forms with A. gibbiger a distinct sister pair (for shared characters see the discussion under the latter species). It seems to be the only Nearctic species of the A. neglecta group where non-sexual dichroism has not been found (even in the male sex), thus resembling in this way the Palaearctic members of this species group. The male of A. orthogibbus can be easily distinguished from all Nearctic relatives not only by the elongate and distally tapered shape of the gonostylus ( Fig. 448 ) but also by the strikingly short ctenidial spine on the f 1 (being as long as or shorter than the maximum width of t 1). For other differences from the related A. gibbiger , see the above description; the most diagnostic characters of the (often difncult to identify) female are also enumerated in the discussion under A. gibbiger .

Etymology. The name orthogibbus is a Latin noun in apposition with a Greek prenx ortho (= upright hump). It refers to the hump-like structure of the caudal process of the transandrium shared with its closest relative, A. gibbiger .

Biology. Anthomyza orthogibbus is most often associated with sedges, including repeated records from Carex lacustris (Ontario: Sault Ste. Marie; Quebec: Lac St-Francois Nat. Wildlife Area, latter reared from larva), C. aquatilis (Ontario: Sault Ste. Marie), and C. utriculata (Ontario: Echo Bay, Elliot Lake & environs, Lake Superior P. Pk., Pancake Bay P. Pk.). Other sedges include Carex stipata var. stipata ( Fig. 421 ), C. gynandra (Ontario: Sault Ste. Marie), C. oligosperma Michx. (Ohio: Battaglia Bog), Scirpus cyperinus (Ontario: Sault Ste. Marie; Ohio: Kent environs) and S. microcarpus (Ontario: Sault Ste. Marie, Fig. 421 ).

Anthomyza orthogibbus was encountered several times as adults in the Ontario: Echo Bay Marsh site where A. equiseti was studied (see details under that species). It was assumed that these swept adults were associated with another plant in the mixture dominated by Equisetum ssuviatile . Subsequent rearings from bulk samples of organic substrate and overwintered E. ssuviatile stems again suggested that there might have been some Carex component or contaminant present in the samples serving as a source of these adults (wet organic substrate – 2 ♀♀; dry overwintered stems – 3 ♂♂ in boxes and 6 ♂♂ 5 ♀♀ in pails; see under A. equiseti for details). However, nine adults (5 ♂♂ 4 ♀♀) emerged from puparia obtained in the spring as larvae, directly from the nodes of E. ssuviatile , so this plant species must be considered at least an incidental (sufncient) host at certain sites or densities. The possibility that these larvae moved from Carex to the nodes of E. ssuviatile in the fall for one reason or another we think is remote. The pupariation period for eight of these adults was 14.6 ± 0.2 days for males (n = 5) and 14.7 ± 0.3 days for females (n = 3) at 20°C.

Anthomyza orthogibbus is often found syntopically with the usually more numerous A. gibbiger (see discussion under that species). This species has been collected from 14 May (Ohio: Towners Woods Marsh) to 16 September (Ontario: Sault Ste. Marie).

Distribution. This species has the most restricted range of the four Nearctic species of the A. neglecta group but it is also the least frequently encountered species. The available records are from Canada: Manitoba, Ontario, Quebec and United States of America: Illinois, Massachusetts, New York, North Carolina, Ohio, Virginia (see Table 2).

Figures

Figs 381–384. Primary types of the Nearctic species of the Anthomyza neglecta group. 381 – A. variegata (Loew, 1863), lectotype male, laterally and type labels, body length 2.50 mm; 382 – A. dichroa sp. nov., holotype male, laterally, body length 2.74 mm; 383 – A. gibbiger sp. nov., holotype male, laterally, body length 2.78 mm; 384 – A. orthogibbus sp. nov., holotype male, laterally, body length 2.62 mm. Photo by J. Roháček.

Figs 437–440. Wings of the Nearctic species of the Anthomyza neglecta group. 437 – A. variegata (Loew, 1863) male, wing length 2.4 mm (USA:Tennessee); 438 – A.dichroa sp.nov., male, wing length 2.5 mm (Canada:Ontario); 439 – A. gibbiger sp. nov., male, wing length 2.3 mm (Canada: Ontario); 440 – A. orthogibbus sp. nov., male, wing length 2.5 mm (Canada: Ontario). Photo by K. N. Barber.

Figs 441–448. Anthomyza orthogibbus sp. nov., paratype male (Canada: Ontario). 441 – external genitalia, caudally; 442 – transandrium, dorsally; 443 – external genitalia, laterally; 444 – hypandrial complex, laterally; 445 – transandrium, caudally; 446 – aedeagal complex, laterally; 447 – apex of nlum, subventrally; 448 – gonostylus, lateroventrocaudally, widest extension. Scales = 0.05 mm (Fig. 447) and 0.1 mm (others).

Figs 449–455. Anthomyza orthogibbus sp. nov., paratype female (Canada: Ontario). 449 – spermatheca; 450 – postabdomen, dorsally; 450a – lateral outline of T7+S7; 451 – postabdomen, ventrally; 452 – female internal sclerites, laterally; 453 – the same, ventrally; 454 – spermatheca; 455 – distal part of female genital chamber, laterally. Scales = 0.05 mm (Figs 449, 454), 0.2 mm (Figs 450, 450a, 451) and 0.1 mm (others).

Figs 419–421. Living Anthomyza gibbiger sp. nov. and its habitat. 419 – A. gibbiger sp. nov., male, pale form, dorsally, body length ca. 2.6 mm; 420 – same specimen, laterally (Canada: Ontario: Sault Ste. Marie, Finn Hill); 421 – wet meadow at Sault Ste. Marie (Finn Hill), habitat of three species of the A. neglecta group, viz. A. gibbiger, A. orthogibbus and A. dichroa. Photo by J. Roháček.