Class Mammalia Linnaeus, 1758 - mammals
   Subclass Theria Parker & Haswell, 1897
     Order Carnivora Bowdich, 1821 - carnivores
       Suborder Caniformia Kretzoi, 1943
         Family Mustelidae Batsch, 1788 - weasels, badgers, skunks, and otters
           Subfamily Lutrinae Bonaparte, 1838 - otters
             Genus Pteronura Gray, 1837 [monotypic] - giant otter
               Pteronura brasiliensis (Gmelin, 1788) - giant otter
                 1 [Pteronura brasiliensis brasiliensis] (Gmelin, 1788)
                 2 Pteronura brasiliensis paraguensis (Schinz, 1821)