Class Mammalia Linnaeus, 1758 - mammals Subclass Theria Parker & Haswell, 1897 Order Didelphimorphia Gill, 1872 Family Didelphidae Gray, 1821 - American opossums Subfamily Didelphinae Gray, 1821 Genus Monodelphis Burnett, 1830 - short-tailed opossums Monodelphis domestica (Wagner, 1842) - gray short-tailed opossum