Vertebrata Cuvier, 1812 - vertebrates
   Gnathostomata
     Teleostomi
       Tetrapoda Hatschek & Cori 1896 [Gauthier, Kluge & Rowe 1988]
         Amniota Haeckel, 1866 [Gauthier, Kluge & Rowe 1988] - amniotes
           Class Mammalia Linnaeus, 1758 - mammals
             Subclass Theria Parker & Haswell, 1897
               Theria of Metatherian-Eutherian grade
                 Infraclass Eutheria Gill, 1872
                   Order †Notoungulata Roth, 1903
                     Suborder †Typotheroidea see Suborder Typotheria Zittel, 1892
                       Superfamily †Hegetotheroidea see Suborder Hegetotheria Simpson, 1945
                         1 Family †Archaeohyracidae Ameghino, 1897
                         2 Family †Hegetotheriidae Ameghino, 1894