The Eocene vertebrate fossil record of the Ainsa Basin (Huesca, Spain): new sirenian fossil sites in the Sobrarbe Deltaic Complex
Keywords:Sirenia, Testudines, Lophiodontids, Lutetian, Southern Pyrenees
AbstractIn the last years, the previously unknown Eocene macrovertebrate fossil record of the Ainsa Basin (Southern Pyrenees Basin, Huesca, Spain) has been improved. It is composed by pleurodiran and cryptodiran testudines and the basal sirenian Sobrarbesiren cardieli. In 2018, a survey campaign was conducted to search for new Eocene sirenian fossil sites in the Ainsa Basin. Thirty-three new sites with macrovertebrate fossils were found increasing to a total of forty the number of fossiliferous points in this basin. They are mainly concentrated in the deltaic plain facies of the Sobrarbe Fm. (middle Lutetian) but the fossil record covers a temporal range from the upper Ypresian? to the late Lutetian-Bartonian. Principally, the recovered fossils are testudines, sirenians and scarce crocodiles, but also a lophiodontid perissodactyl and other still indeterminated mammals evindencing that the Ainsa Basin is a very important area to study Eocene mammals and specially sirenians.