[Photo] A photograph of the Dunkleosteus terrelli fossil skull. This ancient fish had a bite that exerted 11,000 pounds of force, the strongest bite of any fish ever, and one of the strongest bites of any animal. The bladed dentition focused the bite force into a small area, the fang tip, at an incredible force of 80,000 pounds per square inch. Credit: Photograph by Michael LaBarbera, courtesy of The Field Museum

It was big. It was mean. And it could bite a shark in two.

Scientists say Dunkleosteus terrelli might have been "the first king of the beasts." The prehistoric fish was 33 feet long and weighed up to four tons. It had bladed jaws, a flesh-tearing feature that the sharks it preyed upon had not yet developed.

Now scientists have learned Dunkleosteus had the most powerful jaws of any fish ever, its bite rivaling that of T. rex and modern alligators.

The creature lived 400 million years ago.

"Dunkleosteus was able to devour anything in its environment," said study leader Philip Anderson, at the Department of Geophysical Sciences at the University of Chicago.

Scientists already knew Dunkleosteus was the dominant predator of its time.

But Anderson and Mark Westneat, Curator of Fishes at the Field Museum in Chicago, used a fossil of the creature to make a computer model of its muscles and its bite. They conclude that could chomp with 11,000 pounds of force, which translates to 80,000 pounds per square inch at the tip of a fang.

And it was quick, opening its jaws in just one fiftieth of a second. That action would have created suction to draw prey into its mouth.

Fish typically have a powerful bite or a fast bite, but not both, the researchers said.

The research is detailed in the Nov. 29 issue of the Royal Society journal Biology Letters.

Dunkleosteus was one of many species of placoderms, a diverse group of armored fishes that dominated aquatic ecosystems during the Devonian period, from 415 million to 360 million years ago. The beast's powerful bite would have allowed it to feed on other armored aquatic creatures of the time, including sharks and arthropods.