Order †Ornithischia Seeley, 1887 Parvorder †Genasauria Sereno, 1986 see Clade Genasauria Sereno 1986 Nanorder †Cerapoda Sereno, 1986 see Suborder Cerapoda Sereno, 1986 1 Hypoorder †Euornithopoda Sereno, 1986 see Clade Euornithopoda Sereno 1986 2 Hypoorder †Marginocephalia Sereno, 1986 see Clade Marginocephalia Sereno 1986