Phylum Chordata Bateson, 1885 - chordates Subphylum Vertebrata Cuvier, 1812 - vertebrates Class Mammalia Linnaeus, 1758 - mammals Order Marsupialia Jameson, 1818 - marsupials see Cohort Marsupialia Jameson, 1818 Family Didelphidae Gray, 1821 - American opossums