Phylum Chordata Bateson, 1885 - chordates
   Subphylum Vertebrata Cuvier, 1812 - vertebrates
     Class Reptilia Linnaeus, 1758 - 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
             1 Order †Nothosauria Baur, 1889 - nothosaurs see Suborder Nothosauria Baur, 1889
             2 Order †Plesiosauria Blainville, 1835 - plesiosaurs