New occurrence of the genus Dakosaurus (Reptilia, Thalattosuchia) in the Upper Jurassic of north-eastern Mexico, with comments upon skull architecture of Dakosaurus and Geosaurus

A portion of a cranium from the Kimmeridgian La Casita Formation at Zaragoza, Nuevo Leon, north-eastern Mexico, is described and referred to the thalattosuchian genus Dakosaurus. The specimen is too incomplete for further determination or detailed comparison with forms known from Europe and South America. It represents the second occurrence in the Late Jurassic Mexican Gulf of the genus, which had been conspicuously absent from previous studies of the marine reptiles assemblages. The peculiar supratemporal anatomy of Dakosaurus and Geosaurus is examined in terms of muscle attachment and function.