Class Mammalia Linnaeus, 1758 - mammals Order Didelphimorphia Gill, 1872 Family Didelphidae Gray, 1821 - American opossums Subfamily Didelphinae Gray, 1821 Genus Marmosa Gray, 1821 - murine opossums Marmosa canescens (J.A. Allen, 1893) - greyish mouse-opossum see Tlacuatzin canescens (Allen, 1893)