Cricosaurus (Thalattosuchia, Metriorhynchidae) survival across the J/K boundary in the High Andes (Mendoza Province, Argentina)

Abstract

Metriorhynchidae is an extinct group of Jurassic–Cretaceous crocodylomorphs that developed a fully pelagic lifestyle. Its Jurassic record is outstanding (it includes around 40 nominal species), while the records that can be restricted to the Cretaceous are particularly sparse. Here we describe a partial skull of a new species of Cricosaurus, Cricosaurus puelchorum sp. nov., from the lower Berriasian of the Vaca Muerta Formation (Neuquen Basin, Argentina). The description of the specimen reveals a series of autapomorphies and a unique combination of characters that justify the creation of a new species. Phylogenetic analysis places Cricosaurus puelchorum sp. nov. closer to three upper Kimmeridgian–lower Tithonian species of southern Germany. The new taxon was recovered in connection with an accurate ammonoid-based biostratigraphic control and allows confirming the survival of Cricosaurus across the J/K boundary at the southeastern Pacific.