NEW UNIONIDA (BIVALVIA) FROM THE KIMMERIDGIAN (LATE JURASSIC) OF ASTURIAS, SPAIN, AND THEIR PALAEOBIOGEOGRAPHICAL IMPLICATIONS

This study focuses on new records of freshwater bivalves from the Late Jurassic Vega, Terenes and Lastres formations of Asturias, northern Spain. Five new taxa Mujanaia abeuensis gen. et sp. nov., 'Unio' asturianus sp. nov., Margaritifera? lagriega sp. nov., Asturianaia colunghensis gen. et sp. nov. and Asturianaia lastrensis gen. et sp. nov. are described and included in the families Unionidae and Margaritiferidae (Unionida); they are compared and contrasted with other European, Asiatic and North American species. Their discovery constitutes the oldest records of Unionida in Spain, and they provide new palaeogeographical data on the distribution and origin of this group in Europe. These taxa are also an effective tool for the environmental reconstruction of the Jurassic ecosystems of Spain's Dinosaur Coast.