Vertebrata Cuvier, 1812 - vertebrates Gnathostomata Class Chondrichthyes Huxley, 1880 - cartilaginous fishes 1 Subclass Elasmobranchii Bonaparte, 1838 - shark-like fishes 2 Subclass Holocephali 3 Order †Iniopterygiformes 4 Order †Petalodontida see Order Petalodontiformes