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 Catarrhini Geoffroy Saint-Hilaire, 1812
             Superfamily Cercopithecoidea Gray, 1821
               Family Cercopithecidae Gray, 1821 - Old World monkeys
                 Subfamily Colobinae Jerdon, 1867
                   Genus Piliocolobus Rochebrune, 1887
                     Piliocolobus foai (de Pousargues, 1899)
                       1 [Piliocolobus foai foai]ᵀ (de Pousargues, 1899)
                       2 Piliocolobus foai ellioti (Dollman, 1909)
                       3 Piliocolobus foai oustaleti (Trouessart, 1906)
                       4 Piliocolobus foai parmentierorum (Colyn & Verheyen, 1987)
                       5 Piliocolobus foai semlikiensis (Colyn, 1991)