Dinosauria Owen 1841 †Ornithischia Seeley 1887 see Order Ornithischia Seeley, 1887 †Genasauria Sereno 1986 †Neornithischia Cooper 1985 1 †Ornithopoda Marsh 1881 see Infraorder Ornithopoda Marsh, 1881 2 †Marginocephalia Sereno 1986