Acharax costellata (M’Coy, 1844)

Bailey, Jack Bowman, 2021, The genera that never were: The impact of Janeia and Janacekia on phyletic and taxonomic relations within the Solemyidae (Bivalvia: Protobranchia), Palaeontologia Electronica (a 12) 24 (1), pp. 1-47 : 27

Acharax costellata (M’Coy, 1844) sp. inq.

Remarks. Needs further study. Reviewed by Bailey (2011, p. 30). Hind (1900, p. 441) compared the form as similar to S. primaeva but with radial ribs weak to obsolescent. M’Coy’s (1844, p. 48) original description is limited; the holotype, figured both by M’Coy (1844) and by Hind (1900), is an ambiguous shell fragment. Possibly useful if Hind’s (1900, in part, pl. 50, figs. 8-10, non fig. 7) hypotypes are given priority. If so, one of de Koninck’s (1885, pl.

23, fig. 31) examples of Solemya saginata is a possible synonym. Compares with Acharax radiata

(Meek and Worthen) but not with A. primaeva (Phillips) .

? 1844 Sanguinolites costellatus M’Coy , p. 48, pl. 8, fig. 5 [nom. dub.; gen. et. sp. indet. Pr2; fragmentary; longiterminal half missing; hinge unknown; short radial ribs faint but limited to breviventral margin]; Carboniferous, Ireland.

non 1854 Solemya saginata de Ryckholt , (“1847”), p. 53, pl. 11, figs. 9, 10 [= Dystactella cf. subnasuta ]; l’argile carbonifère, Antoing, Belgium.

? 1885 Solemya saginata de Ryckholt ; de Koninck, p. 121, pl. 23, figs. 31 [Pr2, Pc Ne?], 32? [Pr2, Pc]; Lower Carboniferous (Tournaisian), calcaire carbonifère, Tournai, Belgium.

? 1900 Solemya costellata M’Coy ; Hind, p. 442, pl. 50, fig. 13 [Pr2, fragmentary; gen. et sp. indet.; Hind’s own figure of M’Coy’s (1844) holotype]; Carboniferous , Killyclogby, Lisbellaw, Co. Tyrone, N. Ireland .

p 1900 Solenomya costellata ; Hind, p. 442, pl. 50, fig. 8 [Pr2, PAe], fig. 9 [Pr3, Bts?], fig. 10 [Pr2]; non fig. 7; Lower Carboniferous, Lowick and Redesdale, Northumberland, England.

? p 1900 Solemya excisa de Koninck ; Hind, p. 441, pl. 50 figs. 12, 16 [Pc, Pr2, Bts, PAe, = Acharax cf. costellata ]; Carboniferous, Ardross, Scotland; non pl. 50, figs. 11, 14, 15 [ventrally embayed; Pc, Pr1; = Acharax cf. normali s sensu Howse]; Lower Carboniferous, Lowick, Northumberland. [See also Dystactella excisa (de Koninck) ].