Tetrapoda Hatschek & Cori 1896 [Gauthier, Kluge & Rowe 1988] Amniota Haeckel, 1866 [Gauthier, Kluge & Rowe 1988] - amniotes Synapsida Osborn 1903 [Gauthier et al. 1989] Genus †Ophiacodon Marsh, 1878