New U nionida ( B ivalvia) from the K immeridgian ( L ate J urassic) of A sturias, S pain, and their palaeobiogeographical implications

This study focuses on new records of freshwater bivalves from the L ate J urassic V ega, T ereñes and L astres formations of A sturias, northern S pain. Five new taxa M ujanaia abeuensis gen. et sp. nov., ‘ U nio ’ asturianus sp. nov., M argaritifera ? lagriega sp. nov., A sturianaia colunghensis gen. et sp. nov. and A sturianaia lastrensis gen. et sp. nov. are described and included in the families U nionidae and M argaritiferidae ( U nionida); they are compared and contrasted with other E uropean, A siatic and N orth A merican species. Their discovery constitutes the oldest records of U nionida in S pain, and they provide new palaeogeographical data on the distribution and origin of this group in E urope. These taxa are also an effective tool for the environmental reconstruction of the J urassic ecosystems of S pain's D inosaur C oast.