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 †Notioprogonia Simpson, 1934
                 1 Family †Notostylopidae Ameghino, 1897