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 [Order] †Deltatheroida Kielan-Jaworowska, 1982 Genus †Tsagandelta Rougier, Davis & Novacek, 2015