When The Discovery Channel airs a documentary covering dinosaurs they'll devote a few minutes to aquatic life, mention the Megalodon as "King of All Oceans," and move on with the program. If we rewind the clock from Meg's 16 million years to 400 million years we find another terror in the ocean: Dunkleosteus terrelli.

This four-ton fish grew to 30+ feet in length and had bladed jaws (pic), a unique feature lacking in other marine life of the era. Through computer modeling of a fossilized head (pic), scientists determined Dunk has the most powerful bite of any fish ever to swim in the seas.

The bite to rival that of T. Rex crushed down with 11,000 pounds with 80,000 pounds per square inch at the tip of the fangs. The jaw could close in 1/50th of a second usually sucking its prey into its mouth. Dunk was a placoderm, an armored fish, preying on everything in the water including other armored fish and sharks.

If these in-shore predators lived today you'd find them in regions of Poland, Belgium, Morocco, and North America.