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
                     Family †Pachypleurosauridae Nopcsa, 1928
                       1 Genus †Anarosaurus Dames, 1890
                       2 Genus †Dactylosaurus Gürich, 1884
                       3 Genus †Keichousaurus Young, 1958
                       4 Genus †Neusticosaurus Seeley, 1882
                       5 Genus †Pachypleurosaurus Broili, 1927
                       6 ?Genus †Psilotrachelosaurus Nopcsa, 1928
                       7 Genus †Phygosaurus Arthaber, 1924