Chordata Bateson, 1885 - chordates
   Class Elasmobranchii Bonaparte, 1838 see Subclass Elasmobranchii Bonaparte, 1838
     Subclass Selachii see Subdivision Selachii
       Order Notidani Jaekel, 1911 [monotypic] see Order Hexanchiformes Compagno, 1973
         1 Suborder Opistharthri [monotypic] see Order Hexanchiformes Compagno, 1973