Corosaurus alcovensis Case and the phylogenetic interrelationships of Triassic stem-group Sauropterygia

The holotype and other material of Corosaurus alcovensis Case from the Alcova Limestone of Casper, Wyoming, was further prepared using a combination of chemical techniques. Anatomical revision resulted in the definition of new characters for the analysis of the phylogenetic interrelationships of Triassic stem-group Sauropterygia that document paraphyly of the Eusauropterygia. Corosaurus is the sister-taxon to a clade comprising Cymatosaurus, Pistosaurus, and by extension, plesiosaurs and pliosaurs.