Fossil Sea Cow Remains (Mammalia: Sirenia) on Paving Stones in the City of Girona (Catalonia, Spain)

Abstract

Remains of an extinct sea cow are identified on several paving stones in the city of Girona (Catalonia, NE Spain). The limestone slabs are of middle Eocene age, making the fossil one of the oldest representatives of its group in Europe. Based on macroscopic and CT scan data, our study provides first results on the individual age and taxonomic identification of the find. The sea cow remains represent a single specimen. The relative position and degree of wear of the third upper molar indicate a subadult or young adult. Analysis of basicranial sutures and of the third upper molar indicate a young adult. Morphological comparisons focusing on Eocene taxa from Europe that are considered valid and belong to the Dugongidae argue for a closer relationship of the Girona specimen with the genus Prototherium. Given the palaeobiogeographic and stratigraphic distribution of the species available for comparison, the Girona sea cow is tentatively assigned to P. ausetanum. Ongoing post-processing of the CT scans and subsequent 3D reconstruction of the preserved bones are expected to enhance the morphological and taxonomic interpretation and will provide new insights into the evolutionary history and diversity of Eocene sirenians. For this reason, the city of Girona, which already maintains a system of touristic routes for explaining the local geology and palaeontology, will include the scientifically significant site of discovery in its cultural tourism programme. The sea cow remains will be included in the “Inventory of Areas of Geological Interest”, a catalog summarizing the geological history of Catalonia.