Class Mammalia Linnaeus, 1758 - mammals Order Didelphimorphia Gill, 1872 Family Didelphidae Gray, 1821 - American opossums Subfamily Didelphinae Gray, 1821 Genus Thylamys Gray, 1843 Thylamys pusilla (Desmarest, 1804) see Thylamys pusillus (Desmarest, 1804)