Phylum [Vertebrata] Lamarck, 1801 see Infraphylum Vertebrata Lamarck, 1801 Class Reptilia Linnaeus, 1758 - reptiles Subclass †uncertain Order †Plesiosauria Blainville, 1835 - plesiosaurs Family †Plesiosauridae Gray, 1825 Genus †Plesiosaurus De la Beche & Conybeare, 1821