Arganthomyza carbo 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 : 62-66

Arganthomyza carbo Roháček & Barber, 2013

( Figs 66–68 , 70–84 , 164 )

Arganthomyza carbo Roháček & Barber, 2013: 13 .

Type material. HOLOTYPE: ♂, “CAN:ON: SSMarie, Base-line Rd. , 26.vi.2005, KNBarber, sweeps, Aster , Rubus , Equisetum , Carex , ferns, under aspen 46°31.40'N 84°24.40'W ” and “ HOLOTYPUS ♂, Arganthomyza carbo sp.n., J. Roháček & K. N. Barber det.2011” [red label] ( DEBU, intact, see Fig. 164 ) . PARATYPES: 121 ♂♂ 126 ♀♀ ( AMNH, CASC, CNCI, DEBU, LACM, LEMQ, SEMC, SMOC, USNM) (details in ROHÁĆEK & BARBER 2013).

Other material examined (not included in type series). 1 ♀ (used for molecular analysis, details in ROHÁĆEK & BARBER 2013).

Additional records. CANADA: ONTARIO: Moosonee, 51°16.54'N 80°39.00'W, sweeps, Equisetum , Rubus , Cornus , graminoids, edge of wet forest trail, 10.vii.2014, 1 ♀; Moosonee, 51°16.33'N 80°39.11'W, sweeps, mostly Rubus , Impatiens , under Salix , Alnus , 10.vii.2014, 1 ♀, 11.vii.2014, 1 ♂, all K. N. Barber leg. (all CNCI); S[ault] S[te.] Marie, Baseline Rd., 46°31.40'N 84°24.40'W, sweeps, mostly ferns under aspen, 27.vii.2012, 1 ♂ 1 ♀, sweeps, Aster , Rubus , Equisetum , Carex , ferns, under aspen, 24.viii.2013, 1 ♂, K. N. Barber leg. ( INHS). QUEBEC: Mt. Orford, 1200–2000', 21.vii.1968, 1 ♀, J. R. Vockeroth leg. ( CNCI); Ste.-Anne-de-Bellevue, 19.vi.1973, 1 ♀, W. Boyle leg. ( LEMQ). UNITED STATES OF AMERICA: NORTH CAROLINA: Spruce Mt., Smoky Park [GSMNP], 10.vi.1970, 1 ♀, FFS & JEW leg. ( UGCA).

Diagnosis. Male 2.06–3.14 mm, female 2.32–3.55 mm. Primarily blackish brown to black species ( Figs 66–68 , 164 ), very sparsely dark grey microtomentose and distinctly shining; postgena, ventral margin of gena and of occiput entirely blackish; face greyish brown; haltere, parafacialia entirely and anterior portion of frons, ventral corner of sternopleuron and large portions of antennae, mouthparts, gena, legs contrasting ochreous, yellow or whitish yellow; in female, mouthparts with clypeus distinctly darker and palpus brown and nrst antennal nagellomere dorsobasally darker. Frontal triangle very long, reaching anterior margin of frons. Mid basitarsus with 1–2 short dark setae and hind basitarsus with 2–3 (1–2 longer and thicker) short thickened setae. T1 and T2 completely fused to form syntergum T1+2, with only fusion line indicated. Wing hyaline ( Fig. 84 ).

Male genitalia ( Figs 70–76 ). Epandrium ( Figs 70, 71 ) blackish brown, slightly higher than long. Gonostylus ( Figs 70, 71, 76 ) broad and nat, brown, of ham-shaped outline. Postgonite prolonged and strongly curved, sickle-shaped ( Fig. 72 ); caudal process of transandrium reduced ( Fig. 73 ).

Female postabdomen and genitalia (see Figs 77–83 for details). T7 and S7 completely fused into dark brown ring-shaped tergosternum ( Figs 78, 79 ). Ventral receptacle ( Fig. 77 ) arched, wrinkled with distal fourth or nfth smooth with slender nnger-like projection at apex (similar to that in other members of the A. setiplanta group). Spermathecae (1+1) irregularly ovoid (slightly bent), both of similar size or one slightly larger ( Fig. 81 ), with nnely ringed surface except for plain basal fourth and 7–8 spine-like appendages around duct insertion; cervix pale-pigmented, separate. For detailed description see ROHÁĆEK & BARBER (2013).

Discussion. Arganthomyza carbo is the only Nearctic representative of the A. setiplanta group which otherwise includes A. setiplanta from Nepal and A. versitheca from Korea. Based on genitalic and postabdominal characters, A. carbo seems to be most closely allied to the Korean species A. versitheca (cf. ROHÁĆEK & BARBER 2013). Arganthomyza carbo can be safely distinguished from most other Nearctic congeners (except A. vittipennis with patterned wings) by its completely black occiput and postgena, its hind and mid basitarsus with 1–2 short proximoventral dark setae, abdominal T1 and T2 completely fused, and many genitalic characters of which the most salient are mentioned in the key and in the above diagnosis.

Biology. Like all other species of the genus, little is known about the biology of A. carbo . Habitats where this species has been collected can be generally described as mesic mixed woodland (often dominated by trembling aspen, Populus tremuloides Michx. in Ontario, see Fig. 69 ) in openings or edges of trails where thick and diverse undergrowth communities thrive. It is our suspicion that ferns are at least indicators of suitable habitat for A. carbo and possibly also more generally for A. vittipennis , A. bivittata and A. duplex , which can also co-occur with A. carbo , especially the more common A. vittipennis and A. duplex (see Biology section of latter species and comments about ferns above in discussion of wing pattern and its signincance). Collections of adults have been made as early as 1 June (Quebec: Magog) and as late as 18 September (Ontario: Sault Ste. Marie).

Distribution. Generally distributed in northeastern North America ( Canada: Newfoundland, Nova Scotia, Ontario, Quebec; United States of America: Maine, Massachusetts, New Hampshire, New York, North Carolina, Tennessee, Virginia, West Virginia) with two specimens from western Canada (Alberta: Edmonton) ( ROHÁĆEK & BARBER 2013, see Table 2, Figs 599 , 604 ).

Figures

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).

Figs 70–76. Arganthomyza carbo Roháček & Barber, 2013, paratype male (Canada: Ontario). 70 – external genitalia, caudally; 71 – the same, laterally; 72 – hypandrial complex, laterally; 73 – transandrium, caudally; 74 – apex of nlum of distiphallus, anteroventrally (widest extension); 75 – aedeagal complex, laterally; 76 – gonostylus, ventrolaterally (widest extension). Scales = 0.1 mm. Adapted from ROHÁĆEK & BARBER (2013: Figs 53–59).

Figs 77–83. Arganthomyza carbo Roháček & Barber, 2013, paratype female (Canada: Ontario). 77 – ventral receptacle, laterally; 78 – postabdomen, dorsally; 79 – the same, ventrally; 80 – apex of postabdomen and female genital chamber, laterally; 81 – spermathecae; 82 – internal sclerites, ventrally; 83 – the same, laterally. Scales = 0.2 mm (Figs 78, 79), 0.1 mm (Fig. 80) and 0.05 mm (others). Adapted from ROHÁĆEK & BARBER (2013: Figs 60–66).

Figs 84–85.Wings of the Nearctic species of Arganthomyza. 84 – A. carbo Roháček & Barber, 2013, paratype male, wing length 2.8 mm; 85 – A. vittipennis (Walker, 1857), male, wing length 2.6 mm (both Canada: Ontario). Photo by K. N. Barber. Fig. 84 adapted from ROHÁĆEK & BARBER (2013: Fig. 166).

Figs 164–167.Primary types of Arganthomyza species and habitat of A. disjuncta Roháček & Barber, 2013. 164 – A. carbo Roháček & Barber, 2013, holotype male, laterally; 165 – A. disjuncta, holotype female, laterally; 166 – roadside grasses with predominant Bromus inermis near Little Highwood Pass (Canada: Alberta), habitat of A. disjuncta; 167 – detail of the habitat growth with Bromus inermis at Cadomin (both Canada: Alberta). Photo by J. Roháček (Figs 164, 165) and K. N. Barber (Figs 166, 167). Adapted from ROHÁĆEK & BARBER (2013: Figs 2, 4, 104, 105).

Fig. 599. Map of North America showing distributions of two members of Cluster 3 and one member of Cluster 4. Cluster 3: Anthomyza equiseti sp. nov. and A. mcalpinei sp. nov.; Cluster 4: Arganthomyza carbo Roháček & Barber, 2013. The square symbols for A. carbo are enlarged to improve visibility at common localities; there are several records (spots) common to A. equiseti and A. mcalpinei where the latter is not visible, particularly three records running south from James Bay (Ontario: Moosonee). See “Distributional patterns” for explanation of Clusters.

Fig. 604. Phylogeny and its biogeographic implication for species of the Arganthomyza setiplanta group.