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 Family Viperidae Oppel, 1811 - vipers and pit vipers Subfamily Crotalinae Oppel, 1811 - pit vipers Genus Agkistrodon de Beauvois, 1799