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]
               Order †Placodontia Owen, 1859, incertae sedis
                 1 ?Family †Helveticosauridae Peyer, 1955
                 2 Family †Placodontidae Cope, 1871
                 3 Family †Cyamodontidae Nopcsa, 1923
                 4 Family †Henodontidae Huene, 1936