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 Tethytheria McKenna, 1975
             1 Order Proboscidea Owen, 1859 - elephants
             2 Order Sirenia Gill, 1872 - sea cows
             3 Order †Desmostylia Reinhart, 1953