Ophidia Brongniart, 1800
   Serpentes see Suborder Serpentes Linnaeus, 1758
     Alethinophidia Nopcsa, 1923 see Infraorder Alethinophidia Nopcsa, 1923
       Caenophidia Hoffstetter, 1939
         Viperoidea Oppel, 1811 see Superfamily Colubroidea Oppel, 1811
           1 Family †Anomalophiidae Auffenberg, 1959
           2 Family †Russellophiidae Rage, 1975
           3 Family Xenodermatidae Gray, 1849 see Family Xenodermidae Gray, 1849
           4 Family Pareatidae Hoffmann, 1890
           5 Family Viperidae Oppel, 1811 - vipers and pit vipers