Late Aptian-Albian primitive Radiolitidae (bivalves, hippuritoidea) from Spain and SW France

The late Aptian-Albian radiolitid taxa, Praeradiolites cantabricus (Douvillé) and Praeradiolites ibizanus Astre, from SW France and Spain, are transferred to Eoradiolites. Eoradiolites jumillensis nov. sp. is described from southern Spain, while the so-called “Sphaerulites cantabricus” sensu Toucas (1907) is moved to Praeradiolites and may be of Late Cretaceous age. The Eoradiolites cantabricus group of species is mainly Clansayesian-early Albian in age and possesses an advanced evolutionary status, mainly regarding shell size and cellular structure. Praeradiolites may have been derived from Eoradiolites jumillensis nov. sp. through paedomorphosis while Eoradiolites cantabricus may have been the source for Sphaerulites. Our study shows that the names Sphaerulites and Praeradiolites cannot be applied to pre-Cenomanian Radiolitidae and that Eoradiolites was the foremost genus in Late Aptian-Albian times in terms of species biodiversity. The Eoradiolites cantabricus group is restricted to the northwestern Mediterranean Tethyan margin.