Mammaliaformes Rowe 1988
   [crown] Class Mammalia Linnaeus, 1758 - mammals
     Subclass Theriiformes Rowe, 1988 see Division Theriiformes Rowe, 1988
       Infraclass Holotheria Wible, Rougier, Novacek, McKenna & Dashzeveg, 1995 see Clade Holotheria Wible, Rougier, Novacek, McKenna & Dashzeveg 1995
         Superlegion Trechnotheria McKenna, 1975 see Clade Trechnotheria McKenna 1975
           Legion Cladotheria McKenna, 1975 see Clade Cladotheria McKenna 1975
             Sublegion Zatheria McKenna, 1975 see Clade Zatheria McKenna 1975
               Infralegion Tribosphenida McKenna, 1975 see Subclass Boreosphenida Luo, Cifelli & Kielan-Jaworowska, 2001
                 [crown] Supercohort Theria Parker & Haswell, 1897 - therians see Subclass Theria Parker & Haswell, 1897
                   Cohort Placentalia Owen, 1837 - placentals
                     Magnorder Epitheria McKenna, 1975 see Cohort Placentalia Owen, 1837
                       Superorder Preptotheria McKenna, 1975
                         Grandorder Ungulata Linnaeus, 1766
                           Mirorder Eparctocyona McKenna, 1975
                             Order Cete Linnaeus, 1758 see Order Cetartiodactyla Montgelard, Catzeflis & Douzery, 1997
                               Suborder Cetacea Brisson, 1762 - cetaceans see Infraorder Cetacea Brisson, 1762
                                 Infraorder †Archaeoceti Flower, 1883
                                   Family †Protocetidae Stromer, 1908
                                     Subfamily †Protocetinae Stromer, 1908 see Family Protocetidae Stromer, 1908
                                       Genus †Protocetus Fraas, 1904