Dinosauria Owen 1841 [Padian & May 1993], nom. cl. inval. see Clade Dinosauria Owen 1842 [Langer, Novas, Bittencourt, Ezcurra & Gauthier 2020] †Ornithischia Seeley 1887 [Padian & May 1993] see Order Ornithischia Seeley, 1887 †Genasauria Sereno 1986 †Neornithischia Cooper 1985 †Ornithopoda Marsh 1881 see Infraorder Ornithopoda Marsh, 1881 †Euornithopoda Sereno 1986 †Iguanodontia Dollo 1888 †Ankylopollexia Sereno 1986 †Styracosterna Sereno 1986 †Hadrosauriformes Sereno 1997 †Iguanodontidae Cope 1869 see Family Iguanodontidae Cope, 1869