Mammalia Linnaeus 1758 [Rowe 2020] see Class Mammalia Linnaeus, 1758
   Theria Parker & Haswell 1897 [McKenna 1975] see Subclass Theria Parker & Haswell, 1897
     Metatheria Huxley 1880 [O'Leary, Allard, Novacek, Meng & Gatesy 2004] see Infraclass Metatheria Huxley, 1880
       1 †Deltatheroida Kielan-Jaworowska 1982 see Order Deltatheroida Kielan-Jaworowska, 1982
       2 Marsupialiformes Vullo, Gheerbrant, de Muizon & Néraudeau, 2009