Anthomyza pallida (Zetterstedt, 1838)

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 : 141-142

The Anthomyza pallida group

The Anthomyza pallida group was established by ROHÁĆEK (2006a, 2009b), originally for two Palaearctic species, A. pallida ( Zetterstedt, 1838) and A. dissors Collin, 1944 . According to ROHÁĆEK (2009a: Fig. 141 ), the monophyly of this group is well supported and has recently been connrmed by analysis of molecular data ( ROHÁĆEK & TÓTHOVÁ 2014: Fig. 1 ). However, because six more species belonging to this group have been recognized in the Nearctic Region, the diagnosis of the A. pallida group is modined as follows: (1) male f 3 with a series of shortened and thickened setae in distal part of posteroventral row; (2) pregonite with distinctive anterior tooth; (3) phallapodeme with fulcrum arising very near its apex; (4) saccus prolonged, with long membranous distal part; (5) nlum with subterminal widening or tooth; (6) female genital chamber with annular sclerite situated more or less in front of posterior sclerites; (7) spermatheca with distinct terminal invagination.

At present, the group includes 8 species: the Palaearctic A. pallida and A. dissors , and the Nearctic A. pengellyi sp. nov., A. mcalpinei sp. nov., A. pullinotum sp. nov., A. concolor (Thomson, 1869) , A. occidentalis sp. nov. and A. vockerothi sp. nov. These can further be classined under three subgroups, viz. the A. pallida (s. str.) subgroup ( A. pallida and A. pengellyi ), the A. dissors subgroup ( A. dissors , A. mcalpinei and A. pullinotum ) and the A. concolor subgroup comprising only Nearctic species ( A. concolor , A. occidentalis and A. vockerothi ). These subgroups are characterized below in the discussion under A. pengellyi , A. mcalpinei and A. concolor , respectively. While the monophyly of each subgroup is well supported by apomorphic characters, their interrelationships are not so distinct, although the A. pallida subgroup and A. dissors subgroup are likely sister groups, supported by the following synapomorphies: distiphallus with nlum having a distinct dorsal, subterminal tooth or lobelike dilation; female genital chamber with annular sclerite situated distinctly more anteriorly (with respect to other internal sclerites) than in the A. concolor subgroup.

Figures

Figs 139–145. Arganthomyza bivittata Roháček & Barber, 2013, paratype female (Canada: Ontario). 139 – female genital chamber and apex of postabdomen, laterally; 140 – spermatheca; 141, 142 – ventral receptacle, whole laterally (141) and apex ventrally (142); 143 – spermatheca; 144 – internal sclerites, laterally; 145 – the same, ventrally. Scales = 0.1 mm (Fig. 139) and 0.05 mm (others). For abbreviations see p. 11. Adapted from ROHÁĆEK & BARBER (2013: Figs 93–99).

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.