Tetrapoda Hatschek & Cori 1896 [Gauthier, Kluge & Rowe 1988]
   Amniota Haeckel, 1866 [Gauthier, Kluge & Rowe 1988] - amniotes
     Synapsida Osborn 1903 [Gauthier et al. 1989]
       1 Genus †Casea Williston, 1910
       2.1 Genus †Ophiacodon Marsh, 1878
       2.2.1 Genus †Edaphosaurus Cope, 1883
       2.2.2.1 †Sphenacodontinae Romer, 1936
       2.2.2.2 Therapsida Broom, 1905