Vertebrata Cuvier, 1812 - vertebrates see Infraphylum Vertebrata Lamarck, 1801
   Gnathostomata
     Class Chondrichthyes Huxley, 1880 - cartilaginous fishes
       Subclass Elasmobranchii Bonaparte, 1838 - shark-like fishes see Infraclass Elasmobranchii Bonaparte, 1838
         Order †Symmoriida Zangerl, 1981 see Order Symmoriiformes Zangerl, 1981
           1 Family †Symmoriidae Dean, 1909
           2 Family †Stethacanthidae Lund, 1974 see Family Symmoriidae Dean, 1909