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 †Pantolesta McKenna, 1975
                     1 Family †Pantolestidae Cope, 1884
                     2 Family †Pentacodontidae Simpson, 1937 see Subfamily Pentacodontinae Simpson, 1937
                     3 ?Family †Ptolemiidae Carroll, 1988, nom. null. see Family Ptolemaiidae Osborn, 1908