Euclastes acutirostris, a new species of littoral turtle (Cryptodira, Cheloniidae) from the Palaeocene phosphates of Morocco (Oulad Abdoun Basin, Danian-Thanetian)

A new species of the littoral cheloniid turtle Euclastes, E. acutirostris, is proposed, on the basis of a skull from the Palaeocene Phosphates of Morocco, the first turtle record from the Sidi Chennane area. It is estimated to be Danian-Thanetian in age, possibly younger than the previous Danian Moroccan specimens of Euclastes. It differs from the other species of Euclastes mainly by a more elongated and narrower snout, forming a small hook, the presence of a long and narrow spur-shaped postero-inferior process of the jugal, better delimiting the lateral skull emargination and the medially shorter palate, in relation to American Palaeogene specimens. This study indicates the necessity for a world-wide revision of the “Euclastes group” in order to redefine the taxa. It shows the potential interest of the group in the radiation and dispersion of the faunas of the Tethysian and Atlantic margins during the Cretaceous -Tertiary turnover.