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 †Meridiungulata McKenna, 1975 see Grandorder Meridiungulata McKenna, 1975
             Order †Notoungulata Roth, 1903
               Suborder †Hegetotheria Simpson, 1945
                 Family †Hegetotheriidae Ameghino, 1894
                   1 Genus †Pachyrukhos Ameghino, 1885