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 Marmosa Gray, 1821 - murine opossums Marmosa quichua Thomas, 1899 - Quechuan mouse opossum