Squamata Oppel 1811 [Gauthier, Estes & de Queiroz 1988], nom. cl. inval. see Order Squamata Oppel, 1811
   Episquamata Vidal & Hedges, 2005
     Toxicofera Vidal & Hedges, 2005
       Serpentes see Suborder Serpentes Linnaeus, 1758
         1 Family Anomalepididae Taylor, 1939
         2.1.1 Family Leptotyphlopidae Stejneger, 1891 - slender blind snakes
         2.1.2.1 Family Gerrhopilidae Vidal, Wynn, Donnellan & Hedges, 2010 [monotypic]
         2.1.2.2.1 Family Xenotyphlopidae Vidal, Vences, Branch & Hedges, 2010 [monotypic]
         2.1.2.2.2 Family Typhlopidae Merrem, 1820 - blind snakes
         2.2.1.1 Family Aniliidae Stejneger, 1907 [monotypic] - cylinder snakes
         2.2.1.2 Family Tropidophiidae Brongersma, 1951
         2.2.2.1 Family Xenophidiidae Wallach & Günther, 1998 [monotypic]
         2.2.2.2.1.1 Family Bolyeriidae Hoffstetter, 1946
         2.2.2.2.1.2.1 Family Boidae Gray, 1825 [paraphyletic?] - pythons and boas
         2.2.2.2.1.2.1.n Family Calabariidae Gray, 1858 [monotypic]
         2.2.2.2.1.2.2.1.1.1 Family Anomochilidae Cundall, Wallach & Rossman, 1994 [monotypic] - dwarf pipe snakes
         2.2.2.2.1.2.2.1.1.2 Family Cylindrophiidae Fitzinger, 1843 [monotypic] - Asian pipe snakes
         2.2.2.2.1.2.2.1.2 Family Uropeltidae Müller, 1831 - shield-tail snakes
         2.2.2.2.1.2.2.2.1 Family Xenopeltidae Bonaparte, 1845 [monotypic] - sunbeam snakes
         2.2.2.2.1.2.2.2.2.1 Family Loxocemidae Cope, 1861 [monotypic]
         2.2.2.2.1.2.2.2.2.2 Family Pythonidae Fitzinger, 1826
         2.2.2.2.2.1.1 Family Acrochordidae Bonaparte, 1831 [monotypic] - wart snakes
         2.2.2.2.2.1.2 Family Xenodermatidae Gray, 1849 see Family Xenodermidae Gray, 1849
         2.2.2.2.2.2.1 Family Pareatidae Hoffmann, 1890
         2.2.2.2.2.2.2.1 Family Viperidae Oppel, 1811 - vipers and pit vipers
         2.2.2.2.2.2.2.2.1.1 Family Homalopsidae Jan, 1863
         2.2.2.2.2.2.2.2.1.2.1 Family Lamprophiidae Fitzinger, 1843
         2.2.2.2.2.2.2.2.1.2.2 Family Elapidae Boie, 1827
         2.2.2.2.2.2.2.2.2 Family Colubridae Oppel, 1811 - colubrids