Mammalia Linnaeus 1758 [Rowe 1988], nom. cl. inval. see Class Mammalia Linnaeus, 1758
   1 †Aegialodonta Butler, 1978
   2.1 "Eutheria" Gill 1872 [O'Leary, Allard, Novacek, Meng & Gatesy 2004] see Infraclass Eutheria Gill, 1872
   2.2 Metatheria Huxley 1880 [O'Leary, Allard, Novacek, Meng & Gatesy 2004] see Infraclass Metatheria Huxley, 1880