Class Mammalia Linnaeus, 1758 - mammals
   Order Didelphimorphia Gill, 1872
     Family Didelphidae Gray, 1821 - American opossums
       Subfamily Didelphinae Gray, 1821
         Genus Gracilinanus Gardner & Creighton, 1989
           Gracilinanus emiliae (Thomas, 1909) - Emilia's gracile opossum