Phylum [Vertebrata] Lamarck, 1801 see Infraphylum Vertebrata Lamarck, 1801
   Class Reptilia Linnaeus, 1758 - reptiles
     Subclass Diapsida Osborn, 1903 - diapsids see Clade Diapsida Osborn 1903 [Gauthier & de Queiroz 2020]
       Infraclass Archosauromorpha Huene, 1946 see Clade Archosauromorpha Huene 1946 [Benton 1985], nom. cl. inval.
         Superorder Archosauria Cope, 1869 - archosaurs see Clade Archosauria Cope 1869 [Gauthier & Padian 1985], nom. cl. inval.
           Order †Ornithischia Seeley, 1887
             Suborder †Ceratopia see Suborder Ceratopsia Marsh, 1890
               Family †Protoceratopidae see Family Protoceratopsidae Granger & Gregory, 1923
                 1 Genus †Bagataceratops see Genus Bagaceratops Maryanska & Osmólska, 1975
                 2 Genus †Leptoceratops Brown, 1914
                 3 Genus †Microceratops Bohlin, 1953, nom. illeg. see Genus Microceratus Mateus, 2008
                 4 Genus †Montanoceratops Sternberg, 1951
                 5 Genus †Protoceratops Granger & Gregory, 1923