Vertebrata Cuvier, 1812 - vertebrates
   Gnathostomata
     Teleostomi
       Tetrapoda Goodrich, 1930
         Amniota Haeckel, 1866 - amniotes
           Class Mammalia Linnaeus, 1758 - mammals
             Subclass Theria Parker & Haswell, 1897
               Theria of Metatherian-Eutherian grade
                 Infraclass Eutheria Gill, 1872
                   Order Xenarthra Cope, 1889 - xenarthrans see Magnorder Xenarthra Cope, 1889
                     Infraorder Pilosa Flower, 1883 - sloths see Order Pilosa Flower, 1883
                       1 Superfamily Megalonychoidea
                       2 Superfamily †Mylodontoidea Gill, 1872