Mammalia Linnaeus 1758 [Rowe 1988], nom. cl. inval. see Class Mammalia Linnaeus, 1758
   Metatheria Huxley 1880 [O'Leary, Allard, Novacek, Meng & Gatesy 2004] see Infraclass Metatheria Huxley, 1880
     1 Family †Pappotheriidae Slaughter, 1965
     2.1 [Order] †Deltatheroida Kielan-Jaworowska, 1982
     2.2 Marsupialiformes Vullo, Gheerbrant, de Muizon & Néraudeau, 2009