KEY POINTS:
WASHINGTON - It was the first super predator of the ancient seas and its fearsome, jagged jaws still inspire awe 400 million years later.
The armour-plated fish, dunkleosteus, was a 10-metre long, 3600kg monster that terrorised other marine life in the Devonian Period, which spanned 415 million to 360 million years ago.
While lacking true teeth, dunkleosteus used two long, bony blades in its mouth to snap and crush nearly any creature unfortunate enough to encounter it.
Scientists at Chicago's Field Museum and university decided to test dunkleosteus' reputation for wielding some of the most powerful jaws ever on Earth, creating a biomechanical model to simulate its jaws.
They came away impressed.
In research published in the British Royal Society's journal, Biology Letters, they said the big fish's bite packed 5000kg of force.
The bony blades in its mouth, almost certainly enamelled like teeth, concentrated the bite force into a small area at the tip at an astonishing force of 36,000kg per square inch.
That makes dunkleosteus the all-time chomping champion of fish - sorry, sharks.
"It kind of blows sharks out of the water as far as bite force goes," Mark Westneat, curator of fishes at the Field Museum and co-author of the paper, said. "A huge great white shark is probably only capable of biting at about half that bite force. It puts it with big crocodiles and alligators and big dinosaurs like tyrannosaurus rex in terms of the most powerful biters ever."
The researchers also determined that dunkleosteus could open its mouth rapidly - in a 50th of a second - which formed a suction force drawing prey into the mouth. It is rare for a fish to possess a powerful and a fast bite.
Dunkleosteus appeared on Earth about 175 million years before the first dinosaurs and was one of the first jawed vertebrates. It hailed from a group of fish called placoderms, which bore heavy bony armour on the head and neck.
This dominant predator ate just about anything it wanted. The menu included hard-shelled ammonoids with many tentacles, as well as other armoured fish.
It also probably dined on primitive sharks. In fact, sharks achieved greater size and diversity only after dunkleosteus and its like became extinct for reasons unclear to scientists.
"Dunkleosteus was able to devour anything in its environment," said Philip Anderson, of the University of Chicago, the study's lead author.
To gauge its bite force, Westneat and Anderson used a fossilised skull of the species to recreate its musculature. Their resulting biomechanical model showed the jaw's force and motion, with a skull driven by a mechanism based on four rotational joints.
- REUTERS
