Phylum [Vertebrata] Lamarck, 1801 see Infraphylum Vertebrata Lamarck, 1801
   Class Mammalia Linnaeus, 1758 - mammals
     Subclass Theria Parker & Haswell, 1897
       Infraclass Eutheria Gill, 1872
         Cohort Epitheria McKenna, 1975
           Superorder Ungulata Linnaeus, 1766
             Order †Arctocyonia Van Valen, 1969
               Family †Arctocyonidae Giebel, 1855
                 Genus †Chriacus Cope, 1883