Vertebrata Cuvier, 1812 - vertebrates
   Gnathostomata
     Teleostomi
       Tetrapoda Goodrich, 1930
         Amniota Haeckel, 1866 - amniotes
           Class Reptilia Linnaeus, 1758 [paraphyletic] - reptiles
             Subclass Diapsida Osborn, 1903 - diapsids see Clade Diapsida Osborn 1903 [Laurin 1991]
               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