Class Mammalia Linnaeus, 1758 - mammals
   Subclass Theria Parker & Haswell, 1897
     Order Primates Linnaeus, 1758 - primates
       Suborder Haplorrhini Pocock, 1918 see Suborder Haplorhini Pocock, 1918
         Infraorder Simiiformes Haeckel, 1866
           Parvorder Platyrrhini Geoffroy Saint-Hilaire, 1812
             Family Cebidae Bonaparte, 1831 - New World monkeys
               Subfamily Saimiriinae Miller, 1812
                 Genus Saimiri Voigt, 1831 - squirrel monkeys
                   Saimiri ustus (I. Geoffroy Saint-Hilaire, 1843)