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