Dinosauria Owen 1841 [Padian & May 1993], nom. cl. inval. see Clade Dinosauria Owen 1842 [Langer, Novas, Bittencourt, Ezcurra & Gauthier 2020]
Count: -
   †Ornithischia Seeley 1887 [Padian & May 1993] see Order Ornithischia Seeley, 1887
  Count: -
     †Genasauria Sereno 1986
    Count: -
       †Neornithischia Cooper 1985
      Count: -
         †Ornithopoda Marsh 1881 see Infraorder Ornithopoda Marsh, 1881
        Count: -
           1 †Heterodontosauridae Romer 1966 see Family Heterodontosauridae Romer, 1966
          Count: -
           2 †Euornithopoda Sereno 1986
          Count: -