Mammaliaformes Rowe 1988
   [crown clade] Mammalia Linnaeus, 1758 - mammals
     Theriiformes Rowe, 1988 see Division Theriiformes Rowe, 1988
       Holotheria Wible, Rougier, Novacek, McKenna & Dashzeveg, 1995 see Clade Holotheria Wible, Rougier, Novacek, McKenna & Dashzeveg 1995
         Trechnotheria McKenna, 1975 see Clade Trechnotheria McKenna 1975
           Cladotheria McKenna, 1975 see Clade Cladotheria McKenna 1975
             Zatheria McKenna, 1975 see Clade Zatheria McKenna 1975
               Tribosphenida McKenna, 1975 see Subclass Boreosphenida Luo, Cifelli & Kielan-Jaworowska, 2001
                 [crown clade] Theria Parker & Haswell, 1897 - therians see Subclass Theria Parker & Haswell, 1897
                   Placentalia Owen, 1837 - placentals
                     Epitheria McKenna, 1975 see Cohort Placentalia Owen, 1837
                       Preptotheria McKenna, 1975
                         Ferae Linnaeus, 1758
                           Carnivora Bowdich, 1821 - carnivores
                             Caniformia Kretzoi, 1943
                               Arctoidea Flower, 1869
                                 Ursida Tedford, 1976
                                   Phocoidea Gray, 1821
                                     Phocidae Gray, 1821 - true seals
                                       Odobeninae Allen, 1880
                                         Odobenini Allen, 1880
                                           Odobenina Allen, 1880 - walruses see Tribe Odobenini Allen, 1880
                                             †Alachtherium Du Bus, 1867