Dunkleosteus

The largest known species, Dunkleosteus terrelli, was probably about 3.4 metres (11 feet) long for typical adults, and up to 4.1 metres (13 feet) for exceptionally large individuals. Some older estimates were much bigger, but recent studies suggest these smaller sizes.1

No, instead of teeth it had sharp, blade-like bony plates in its jaws that could cut through armoured prey. These blades even sharpened themselves as the fish opened and closed its mouth.13

It ate armoured prey like ammonites and other placoderms, and could even catch fast-swimming fish like Orodus. Fossils show it sometimes regurgitated bones from its last meal.1

It could open its jaws in just 20 milliseconds and complete a feeding snap in 50 to 60 milliseconds, which is as fast as a blink. This helped it catch fast prey.4

No, it was a giant armoured fish that lived in the oceans during the Devonian Period, long before dinosaurs existed. It belonged to a group called placoderms.1

Its bite force was estimated at up to 7,495 newtons, which is among the highest of any fish ever. That is strong enough to puncture armour.14

Fossils have been found in the United States, Canada, Poland, Belgium, Morocco, and Russia. The largest collection is at the Cleveland Museum of Natural History in Ohio.1

It lived during the Late Devonian Period, about 382 to 358 million years ago. That is before the first dinosaurs appeared.1

Yes, it might have been a fast swimmer, not slow as once thought. It could catch fast-swimming fish like Orodus, which suggests it was quick.1

Its thick bone plates on the head and front body protected it from other predators and helped it hunt armoured prey. The plates were up to 7.6 cm (3 inches) thick in some places.1