Mammalia Linnaeus 1758 [Rowe 2020] 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 Marsupialiformes Vullo, Gheerbrant, de Muizon & Néraudeau, 2009 †Ameridelphia Szalay 1982 Sudameridelphia Szalay 1994 Genus †Gaylordia Paula Couto, 1952