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: -
         †Marginocephalia Sereno 1986
        Count: -
           1 †Pachycephalosauria Maryañska & Osmólska 1974 see Infraorder Pachycephalosauria Maryañska & Osmólska, 1974
          Count: -
           2 †Ceratopsia Marsh 1890 see Infraorder Ceratopsia Marsh, 1890
          Count: -