Vertebrata Cuvier, 1812 - vertebrates
   Gnathostomata
     Teleostomi
       Tetrapoda Hatschek & Cori 1896 [Gauthier, Kluge & Rowe 1988]
         Amniota Haeckel, 1866 [Gauthier, Kluge & Rowe 1988] - amniotes
           Class Reptilia Linnaeus, 1758 [paraphyletic] - reptiles
             Subclass Diapsida Osborn, 1903 - diapsids see Clade Diapsida Osborn 1903 [Gauthier & de Queiroz 2020]
               Infraclass Lepidosauromorpha Benton, 1983 see Subclass Lepidosauromorpha Benton, 1983
                 Superorder †Sauropterygia Owen, 1860
                   Order †Nothosauria Baur, 1889 - nothosaurs see Suborder Nothosauria Baur, 1889
                     01 Family †Pachypleurosauridae Nopcsa, 1928
                     02 Family †Simosauridae (Nopcsa, 1928) [monotypic]
                     03 Family †Nothosauridae Baur, 1889
                     04 Family †Cymatosauridae von Huene [monotypic]
                     05 Family †Pistosauridae Zittel, 1887 [monotypic]
                     06 Genus †Corosaurus Case, 1936, incertae sedis
                     07 Genus †Elmosaurus von Huene, 1957, incertae sedis
                     08 Genus †Kwangsisaurus Young, 1959, incertae sedis
                     09 Genus †Metanothosaurus Yabe & Shikama, 1948, incertae sedis
                     10 Genus †Parthanosaurus Skuphos, 1893, incertae sedis