Dunkleosteus

The shark-killer of the Devon period

With a length of almost ten metres, Dunkleosteus was the largest marine predator over 360 million years ago in the Devonian period. The head of this eating machine was enclosed in immobile armour plates, the body, muscular and streamlined, similar to the one of a shark. It hunted predominantly for other large fish, even specimens of its own species. 

The secret of Dunkleosteus was its mouth. The development of a movable lower jaw 420 million years ago was the starting signal for the rapid rise of fish to become the rulers of the seas.

Instead of teeth, Dunkleosteus had two razor-sharp bite plates made of bone, which were inserted scissor-like. The jaws were extremely strong. Anything that got between them was neatly cut in two.

This enabled this fish to hunt, kill and eat other large animals, such as sharks, with an efficiency that jawless creatures could never achieve. The rise of jawed mouths coincides with the decline of many other aquatic creatures, such as trilobites, marine scorpions, and jawless fish. All these animals are thought to have been displaced by animals with jawed mouths.