Phylum Chordata Bateson, 1885 - chordates
   Subphylum Vertebrata Cuvier, 1812 - vertebrates 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 †Pachycephalosauria Maryañska & Osmólska, 1974 see Infraorder Pachycephalosauria Maryañska & Osmólska, 1974
                 Family †Chaoyoungosauridae Zhao, 1983, nom. inval. see Family Chaoyangsauridae Zhao, Cheng, & Xu, 1999
                   Genus †Xuanhuasaurus Zhao, 1985, nom. nud. see Genus Xuanhuaceratops Zhao X., Cheng Z., Xu X. & Makovicky, 2006