The rudist genus Sellaea Di Stefano, 1889 (Bivalvia, Hippuritida) in the Albian carbonate platforms of Cantabria (N Spain): biostratigraphical and paleobiogeographical implications

During the Cretaceous, the gradual and extensive diversification of rudists led this group to colonise the carbonate platforms of tropical seas all over the world, structuring new ecosystems. The Albian genus Sellaea Di Stefano, 1889 has a worldwide distribution ranging from the Caribbean to Tibet, with maximum diversity centered in the Mediterranean province. This genus, recently studied in American faunas, is an important witness of the paleobiogeographical dynamics at work during this process of diversification, which generated significant endemism and helped characterise the paleobiogeographical provinces of the late Early Cretaceous. In order to add to our knowledge of this genus and the paleobiogeography of rudists, we report the existence of Sellaea in Cantabria, Spain. The middle and late Albian age is based on the presence of the ammonite Anahoplites Hyatt, 1900 and the rudists Eoradiolites jumillensis Masse, Fenerci-Masse, Vilas & Arias, 2007 and Caprina choffati Douvillé, 1898. Specimens have been identified as Sellaea stryx (Di Stefano, 1889), a species without pallial canals that belongs to the Mediterranean clade, a sister group to the American Sellaea. After describing in detail the localities where the specimens were found, we show the relevance of the presence of Sellaea stryx in the Cantabrian Albian faunas from a biostratigraphic point of view. We also discuss the impact of the presence of these faunas from a paleobiogeographical point of view.