Arganthomyza duplex Roháček & Barber, 2013

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 : 90-92

Arganthomyza duplex Roháček & Barber, 2013

( Figs 108 , 127 , 146–148 , 150–163 )

Arganthomyza duplex Roháček & Barber, 2013: 26 .

Type material. HOLOTYPE: ♂, “CAN: ON: ~20kmE Nipi-gon, Hwy#17, rest area, 31.vii.2008, KNBarber, sweeps, Aster , Rubus , Aralia , Diervilla 48°58.00’N 87°59.09’W ” and “ HOLOTYPUS ♂, Arganthomyza duplex sp.n., J. Roháček & K. N. Barber det. 2011” [red label] ( DEBU, intact, see Fig. 108 ) . PARATYPES: 670 ♂♂ 707 ♀♀ ( AMNH, BDUC, BIOUG, CASC, CMNH, CNCI, CSUC, DEBU, INHS, KNWR, LACM, LEMQ, MCZC, PMAE, RBCM, SMOC, UBCZ, USNM, ZSMC) (details in ROHÁĆEK & BARBER 2013).

Other material examined (not included in type series). 6 ♂♂ 4 ♀♀ ( CASC, DEBU, LACM, LEMQ, SMOC, damaged) (details in ROHÁĆEK & BARBER 2013).

Additional records. CANADA: ALBERTA: S. Alberta, Cypress Hills, 25.vi.1966, 1 ♂, K. A. Spencer leg. ( BMNH); Dunvegan, 55°55.39'N 118°35.74'W, sweep south facing slope at dusk, 19.vii.2003, 1 ♂ 1 ♀, S. Boucher leg.( LEMQ 0040438, -40); N. Alberta, George Lake, 6.vi.1966, 1 ♀; Jasper, 16.vi.1966, 1 ♂, both K. A. Spencer leg. (both BMNH, both genit. prep.); Sheep Creek Prov.Pk., 54°03.6'N 119°00.7'W, sweep at campground, 22.vii.2003, 2 ♂♂ 1 ♀, S. Boucher leg. ( LEMQ 0040456, -58, -59); Kananaskis, Sheep River Prov. Pk., Sandy McNabb camp, sweep open forest and grasses, 28.vii.2003, 50°38.27'N 114°31.7'W,9 ♂♂ 5 ♀♀, S. Boucher leg. ( LEMQ 0040385, -386, -394–396, -398–406), 6 ♂♂ 3 ♀♀, V. Dion leg. ( LEMQ 0040446–54), 50°38.25'N 114°31.9'W, 1 ♂, S. Boucher leg. ( LEMQ 0040384); same locality but 7 km W Sandy McNabb camp, 50°38.9'N 114°37'W, sweep open forest and neld, 28.vii.2003, 1 ♂ 1 ♀, S. Boucher leg. ( LEMQ 0040408, -09); same locality but Blue Rock campground, 50°36.6'N 114°43.4'W,sweep, 29.vii.2003, 1 ♂, S.Boucher leg.( LEMQ 0040411);St.Albert nr.Edmonton, 1.vi.1966, 1 ♀, K. A. Spencer leg. ( BMNH, genit. prep.); 10 km N Whitecourt, Sakwatamau R., 54°12'03"N 115°46'40"W, sweep edges and grass at upper beach, 18.vii.2003, 1 ♀, T.A. Wheeler leg. ( LEMQ 0040391). BRITISH COLUMBIA: Kaslo, 25.vi.[-], 1 ♂ 1 ♀, R. P. Currie leg. ( SMOC, both genit prep.). ONTARIO: ~ 26 km SSE Chapleau, Island Lake Biomass, 47°38.23'N 83°14.78'W, jack pine forest (~80yr), pitfall traps (1N), 22.vii.–6.viii.2013, 1 ♂; ~ 33 km ESE Hawk Jct., Island Lake Biomass, Ripple Lk, 3-yr post-wildnre, 23.vii.–8.viii.2013, 47°56.11'N 84°09.36'W, pitfall traps (3R), 1 ♂ 3 ♀♀; same locality but 47°55.86'N 84°09.41'W, pitfall traps (5R), 1 ♂, all L. Venier leg. (all INHS); n. Hurkett, km 46.3 Black Sturgeon Rd., 49°11'15''N 88°42'30''W, mixed forest, pifall trap, Stand 1, Site 4, Trap 2, 23.viii.–8.ix.1993, 1 ♂, Site 4, Trap 9, 1 ♀, Site 1A, Trap 9, 1 ♂ 1 ♀, all K. N. Barber leg. ( SMOC, 1 ♂ 1 ♀ genit. prep.); Moosonee, 51°16.33'N 80°39.11'W, sweeps, mostly Rubus , Impatiens , under Salix , Alnus , 10.vii.2014, 2 ♀♀, K. N. Barber leg. ( CNCI). QUEBEC: Lac Roddic, 16 km S Maniwaki, 22.vi.1991, 1 ♀, M. Barták leg. ( MBPC); Laurentide Pk., 7.viii.1956, 1 ♂ 1 ♀, A. H.Sturtevant leg. ( USNM). UNITED STATES OF AMERICA: MONTANA: Lincoln Co., Ross Creek, Giant Cedars Rec.Area, 48°12'N 115°54'W, mature forest, 26.vi.1996, 1 ♀, H. Goulet leg. ( CNCI). NEW HAMPSHIRE: “N.H.”, “205”, “Loew Coll.”,“ Type 14558” (red label), 1 ♀ ( MCZC, double mount (single pin) with a headless ♀ of Anthomyza oblonga on the same pinned bricket, erroneously labelled as type specimens of Anthophilina terminalis Loew ); White Mts. Nat. For., 4 mi S of North Woodstock, Pemigewasset River, 1–4. viii.1980, 1 ♀, A. E. Stubbs leg. ( BMNH, genit. prep.). PENNSYLVANIA: Dubois, 3.ix.1920, 1 ♀, A. L. Melander leg. ( SMOC, genit. prep., Sabrosky det. as A. tenuis ).

Diagnosis. Male 2.10–2.70 mm, female 2.38–3.18 mm. Bicolourous ( Figs 108 , 146–148 ), dark brown and yellow, sparsely grey microtomentose and distinctly shining. Head dark brown with face, parafacialia, gena, postgena, ventral margin of occiput, mouthparts, entire haltere, frons and antennae and all legs largely contrasting ochreous, yellow or whitish yellow. Pleural area of thorax also extensively ochreous to yellow, at least on ventral half; notopleuron and humerus may also be paler than surrounding notum; preabdominal sterna brown in male, pale yellow in female. Frontal triangle reaching anterior fourth of frons. Mid and hind basitarsus without short thickened setae. T1 (usually paler) and T2 almost separate, only laterally partly fused. Wing hyaline ( Fig. 127 ).

Male genitalia (see Figs 150–156 for details). Epandrium ( Figs 150, 151 ) blackish brown, higher than long. Gonostylus ( Figs 150, 151, 156 ) ochreous to yellow, markedly different from that of both A. acuticuspis and A. bivittata , small, relatively narrow and posteriorly bent in lateral view, with broadly rounded apex, somewhat also bent medially ( Fig. 150 ).

Female postabdomen and genitalia (see Figs 157–163 for details). T7 and S7 completely fused to form annular tergosternum T7+S7 ( Figs 158, 159 ); anteroventrally with a long, dark, transverse ledge-like anterior submarginal band ( Fig. 159 ). Ventral receptacle ( Figs 162, 163 ) slender and elongate, similar to those of close relatives, with middle part curved and distinctly ringed, long terminal part slender, plain and straighter but its apex twisted. Spermathecae (1+1) pyriform ( Fig. 157 ), most resembling those of A. acuticuspis including darker constriction in proximal third and surface structure in distal two-thirds, but more elongate and with spines in basal part more transversely arranged; duct with cervix as in the latter species.

Discussion. Although more externally resembling Arganthomyza acuticuspis , A. duplex appears to be a sister species of A. bivittata despite a marked colour dissimilarity, demonstrated by molecular data ( ROHÁĆEK & TÓTHOVÁ 2014: Fig. 1 ) and two synapomorphies: the pale-pigmented female S2–S6; the gonostylus with the apex bent medially (cf. ROHÁĆEK & BARBER 2013: Fig. 173 ).

Among Arganthomyza species, A. duplex is readily distinguished by its bicolourous pleura (dark dorsally, pale ventrally), characteristic gonostylus (bent posteriorly) and sexually dichroic colouration of the preabdominal sterna (brown in male, pale yellow in female) (see also the key above). However, there is externally a very similar species of the Anthomyza macra group in North America, viz. A. silvatica sp. nov. This species usually differs from A. duplex by the reduced subvibrissa, the short setula in front of the anterior orbital seta, and paler pigmentation of the apical tarsal segments, but it is recommended always to verify its identincation by examining male and female genitalic characters.

Biology. Four Nearctic species of Arganthomyza are often found together in eastern North America in at least pairs of species usually involving the more common A. duplex and A. vittipennis . Three sites in Ontario: Sault Ste. Marie are known to have yielded all four species (Baseline Rd., Birchwood Pk., and Bristol Place Pk.) while two other localities (viz., Ontario: Icewater Creek watershed and Moosonee) have yielded all but A. vittipennis .

Most eastern collections of Arganthomyza duplex with habitat data suggest relatively mesic mixed forest (often dominated by aspen, Populus tremuloides Michx. , in Ontario) with thick and diverse ground vegetation ( Fig. 69 ). This understory usually includes a wide variety of plant species and can be variously dominated by a few. The authors have suspected that ferns ( Fig. 149 ) may be at least an indicator of potential habitat but their role as host plants has not been evaluated. Northwestern records suggest a preference for more open habitat such as grasses (Alberta: Dunvegan and Cadomin) and also pine forest (Yukon: Carcross), while some collections have been made in habitats not including ferns in the immediate vicinity (Alberta: Westlock Co.; Ontario: Moosonee). Adult nies have been collected from 9 April (British Columbia: Robson) to 21–28 September (Utah: Tony Grove Jct.).

Distribution. This is the most commonly collected and widely distributed species of Arganthomyza in North America and is transcontinental in both Canada and the northern United States – in Canada, from British Columbia and Yukon to Newfoundland and Nova Scotia (Alberta, British Columbia, Manitoba, New Brunswick, Newfoundland, Nova Scotia, Ontario, Quebec, Saskatchewan, Yukon) and the United States of America, from Alaska, Washington and Idaho to New Mexico, New Hampshire and New York (Alaska, Colorado, Idaho, Michigan, Minnesota, Montana, New Hampshire, New Mexico, New York, Pennsylvania, Utah, Vermont, West Virginia, Wyoming), ( ROHÁĆEK & BARBER 2013, see Table 2). At least some of the most southwestern specimens have been taken at altitudes above 9000 feet [= 2743 m] (Colorado, New Mexico, Utah).

Figures

Figs 106–109. Holotype males of the Nearctic species of the Arganthomyza duplex group. 106 – A. acuticuspis Roháček & Barber, 2013; 107 – A. bivittata Roháček & Barber, 2013; 108 – A. duplex Roháček & Barber, 2013 (all laterally); 109 – A. bivittata, head and thorax dorsally. Photo by J. Roháček. Adapted from ROHÁĆEK & BARBER (2013: Figs 1, 3, 5, 6).

Figs 125–127. Wings of the Nearctic species ofArganthomyza. 125 – A. acuticuspis Roháček & Barber, 2013, paratype male, wing length 2.5 mm (USA: New Mexico); 126 – A. bivittata Roháček & Barber, 2013, paratype male, wing length 2.8 mm; 127 – A. duplex Roháček & Barber, 2013, paratype male, wing length 2.6 mm (both Canada: Ontario). Photo by K. N. Barber. Adapted from ROHÁĆEK & BARBER (2013: Figs 167–169).

Figs 146–149. Living Arganthomyza duplex Roháček & Barber, 2013 and its habitat. 146 – mating pair of A. duplex, laterally, body length ca. 2.3–2.9 mm; 147 – male, laterally, body length 2.5 mm; 148 – female, laterally, body length ca. 3 mm; 149 – fern-dominated undergowth of mixed forest, habitat of A. duplex and A. carbo (all photos from Canada: Ontario: Dubreuilville). Photo by J. Roháček. Fig. 146 adapted from ROHÁĆEK & BARBER (2013: Fig. 100).

Figs 150–156.Arganthomyza duplex Roháček & Barber, 2013,paratype male (Canada:Ontario).150 – external genitalia, caudally; 151 – the same, laterally; 152 – hypandrial complex, laterally; 153 – transandrium, caudally; 154 – apex of nlum, anteroventrally (widest extension); 155 – aedeagal complex, laterally; 156 – gonostylus, lateroventrocaudally (widest extension). Scales = 0.1 mm.Adapted from ROHÁĆEK & BARBER (2013: Figs 106–112).

Figs 157–163. Arganthomyza duplex Roháček & Barber, 2013, paratype female (Canada:Ontario). 157 – spermathecae; 158 – postabdomen, dorsally; 159 – the same, ventrally; 160 – internal sclerites, ventrally; 161 – the same, laterally; 162 – ventral receptacle, whole laterally and apex ventrally; 163 – female genital chamber and apex of postabdomen, laterally. Scales = 0.05 mm (Fig. 157), 0.2 mm (Figs 158, 159) and 0.1 mm (others). Adapted from ROHÁĆEK & BARBER (2013: 113–120).

Fig. 1. Anthomyza dichroa sp. nov., male, general habitus (Canada: Ontario: Sault Ste. Marie, Bristol Place Park), body length ca. 2.5 mm. Based on photograph by J. Roháček.

Figs 168–175. Arganthomyza disjuncta Roháček & Barber, 2013, paratype male (Canada:Alberta). 168 – external genitalia, caudally; 169 – base of phallapodeme, dorsally; 170 – external genitalia, laterally; 171 – hypandrial complex, laterally; 172 – transandrium, caudally; 173 – apex of nlum of distiphallus, anteroventrally (widest extension); 174 – aedeagal complex, laterally; 175 – gonostylus, lateroventrally (widest extension). Scales = 0.05 mm (Figs 173, 175) and 0.1 mm (others). Adapted from ROHÁĆEK & BARBER (2013: Figs 122–128).

Figs 66–69.Living Arganthomyza carbo Roháček & Barber, 2013 and its habitat. 66 – A. carbo, male dorsally, body length ca. 2.7 mm; 67 – same specimen, laterally (Canada: Ontario:Sault Ste. Marie); 68 – same, enlarged, frontally; 69 – undergrowth of humid aspen forest at Baseline Rd. in Sault Ste. Marie, habitat of A. carbo, A. vittipennis, A. bivittata, and A. duplex. Photo by J. Roháček. Adapted from ROHÁĆEK & BARBER (2013: Figs 48–51).