Kingdom [Animalia] Linnaeus, 1758 - animals
   Subkingdom Metazoa Haeckel, 1874 see Kingdom Animalia Linnaeus, 1758
     Division Eumetazoa Butschli, 1910 see Subkingdom Eumetazoa Butschli, 1910
       Subdivision Bilateralia
         Phylum Chordata Bateson, 1885 - chordates
           Subphylum Vertebrata Cuvier, 1812 - vertebrates
             Class Reptilia Linnaeus, 1758 - reptiles
               Subclass Lepidosauria Duméril & Bibron, 1839
                 Order Squamata Oppel, 1811
                   Suborder Serpentes Linnaeus, 1758 - snakes
                     Infraorder Caenophidia Hoffstetter, 1939 see Superfamily Xenophidia
                       Family Viperidae Oppel, 1811 - vipers and pit vipers
                         Genus Atheris Cope, 1862
                         Genus Atractaspis Smith, 1849
                         Genus Azemiops Boulenger, 1888
                         Genus Bitis Gray, 1842
                         Genus Causus Wagler, 1830
                         Genus Cerastes Laurenti, 1768
                         Genus Echis Merrem, 1820
                         Genus Eristicophis Alcock & Finn, 1897
                         Genus Pseudocerastes Boulenger, 1896
                         Genus Vipera Laurenti, 1768