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 Trachypithecus Reichenbach, 1862 - brow-ridged langurs, leaf monkeys
                     Trachypithecus vetulus (Erxleben, 1777)
                       1 [Trachypithecus vetulus vetulus]ᵀ (Erxleben, 1777)
                       2 Trachypithecus vetulus monticola (Kelaart, 1850)
                       3 Trachypithecus vetulus nestor (Bennett, 1833)
                       4 Trachypithecus vetulus philbricki (Phillips, 1927)