Order †Ornithischia Seeley, 1887 Parvorder †Genasauria Sereno, 1986 see Clade Genasauria Sereno 1986 Nanorder †Cerapoda Sereno, 1986 see Suborder Cerapoda Sereno, 1986 Hypoorder †Euornithopoda Sereno, 1986 see Clade Euornithopoda Sereno 1986 Suborder †Ornithopoda Marsh, 1871 see Infraorder Ornithopoda Marsh, 1881 Infraorder †Iguanodontia Dollo, 1888 see Clade Iguanodontia Dollo 1888 Genus †Tenontosaurus Ostrom, 1970