Polycotylids were aof plesiosaurs that originated during the middle phase of the Cretaceous and died out at the end of this period. They were most closely related to leptocleidids with which they formed a larger group named Leptocleidia. In contrast to some of their relatives, elasmosaurids or cryptoclidids, the members of Polycotylidae were characteristic for their relatively short necks, similar to those in pliosaurids, such as the popular Liopleurodon ferox and its kin.
A team of researchers led by Eberhard Frey from the State Museum of Natural History Karlsruhe, Germany, described a new species of polycotylid plesiosaur. The animal was named Mauriciosaurus fernandezi. It’s known from a nearly complete skeleton that was discovered in ~93-million-year-old strata at Vallecillo, northeast Mexico.
The material of Mauriciosaurus represents a juvenile individual that supposedly died some 500 km from the nearest shoreline. It is interesting especially because of its preservation. Except for its completeness, Mauriciosaurus fernandezi was preserved with parts of its soft tissue which is a unique discovery among plesiosaurs.
Even though the authors didn’t perform any phylogenetic analysis, Mauriciosaurus shows similarities to Dolichorhynchops and Trinacromerum.
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