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 Chironectes Illiger, 1811 - yapok 1 Chironectes minimus (Zimmermann, 1780) - water opossum