Pliocene species of Aequipecten (Mollusca, Bivalvia, Pectinidae) from the North Sea Basin

Pliocene deposits in the North Sea Basin have so far yielded three species of the bivalve genus Aequipecten P. Fischer, 1886, viz. A. o. opercularis (Linné, 1758), A. r. radians (Nyst & Westendorp, 1839) and A. wagenaari n. sp. The last-named taxon appears to be restricted to the Early to Middle Pliocene of the North Sea Basin. In the literature, Aequipecten r. radians has been recorded from a number of Miocene and Pliocene localities both within and beyond the North Sea Basin; however, these records have proved erroneous. Material from Aquitaine (France) formerly considered to be assignable to A. r. radians should be referred to A. liberatus (Cossmann & Peyrot, 1914). Material from Touraine and Brittany represents the subspecies, A. r. assimilatus (Millet de la Turtaudière, 1866). Aequipecten opercularis first occurs in the Lower Miocene of Aquitaine, being represented by the subspecies, A. o. pinorum (Cossmann & Peyrot, 1914). Middle Miocene records of A. opercularis are known from the Lower Badenian of Romania.