Among these oceanic giants swam Helicoprion, a unique prehistoric fish that has puzzled scientists for over a century. What sets Helicoprion apart from its contemporaries is a peculiar spiral of ...

The Jurassic shark, Hybodus, had a pair of small horns on its head while another species, Stethacanthus, had a dorsal fin shaped a lot like an iron. Weirdest of all was probably Helicoprion ...