Phylum [Vertebrata] Lamarck, 1801 see Infraphylum Vertebrata Lamarck, 1801
   Class Reptilia Linnaeus, 1758 - reptiles
     Order †Plesiosauria Blainville, 1835, incertae sedis - plesiosaurs
       Family †Elasmosauridae Cope, 1869
         1 Genus †Elasmosaurus Cope, 1868
         2 Genus †Muraenosaurus Seeley, 1874