Dunkleosteus

Devonian Terror of the High Seas
Dunkleosteus was a large, armoured fish that lived roughly 370-355 million years ago. It was carnivorous, and the top predator in the Devonian seas. Its name means 'Dr.David Dunkles Bones'. In the murky depths of the high level seas of the Late Devonian Period, lurked terrifying sea monsters - 10 metre long, 3-4 tonne, carnivorous Placoderm fish; a species known as Dunkleosteus. Dunkleosteus was truly the largest ever Placoderm fish, that has ever been discovered, and although Giant Orthocones from the previous periods of geological time were slightly longer, it was not until the Mesozoic Era and the massive marine reptiles of the time, that anything more terrifying evolved. Armed with huge sheer-like extensions of the jaw bone, Dunkleosteus actually had no teeth proper, however these jaw bone extensions were jagged and capable of slicing through the plate armour skin of even each other, and it has been suggested that it could tear through the toughest chainmail. Obviously, being so large and so well armed, as an adult, Dunkleosteus had only each other to fear, and indeed it is likely that they were cannibals, snapping at youngsters as they would any other potential prey. Therefore, they were the top of the food chain, eating anything they could catch, including early sharks.