Ctenacanthiformes

Ctenacanthiformes is an extinct order of cartilaginous fish. They possessed ornamented fin spines at the front of their dorsal fins and cladodont-type dentition, that is typically of a grasping morphology, though some taxa developed cutting and gouging tooth morphologies. Some ctenacanths are thought to have reached sizes comparable to the great white shark, with body lengths of up to and weights of , while others reached lengths of only . The earliest ctenacanths appeared during the Frasnian stage of the Late Devonian (~383-372 million years ago), with the group reaching their greatest divers