Diapsida Osborn 1903 [Laurin 1991] see Clade Diapsida Osborn 1903 [Gauthier & de Queiroz 2020]
Count: -
   Archosauromorpha xxxHuene 1946 [Gauthier, Kluge & Rowe 1988] see Clade Archosauromorpha Huene 1946 [Benton 1985], nom. cl. inval.
  Count: -
     Archosauria Cope, 1869
    Count: -
       Ornithosuchia see [unranked] Avesuchia Benton, 1999
      Count: -
         Ornithodira Gauthier 1986 see Clade Ornithodira Gauthier 1986 [M. Ezcurra, S. Nesbitt, M. Bronzati, F. Dalla Vecchia, F. Agnolin, R. Benson, ..., M. Langer 2020]
        Count: -
           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: -
                 †Cerapoda Sereno, 1986 see Suborder Cerapoda Sereno, 1986
                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: -