Imagine a giant fish 30 feet long with jaws like a chopping block. Anything that found itself inside the mouth of this fish ended up dead.
382 million years ago nature came up with a new killing machine that dominated the Late Devonian period for over 30 million years. Its name was Dunkleosteus and there has never been another fish like since it went extinct. And its a good thing for us that it did. Dunkleosteus was a placoderm (Armored Fish) meaning that its front half of its body was made up of bone and hard tissue. kind of like a head made out of a turtles shell. It's thought that this large fish would have roamed the shorelines like a modern day great white. How fast this animal could travel through the water is still unknown but there is one feature about this fish that is just terrifying.
Dunkleosteus possessed a four-bar linkage mechanism for jaw opening that incorporated connections between the skull, the thoracic shield, the lower jaw and the jaw muscles joined together by movable joints. This mechanism allowed it to open their jaws in 20 milliseconds and complete the whole process and close in 50–60 milliseconds. That is ridiculously fast for any animal and this was done with the resistance of deep water around it.
The four-bar jaw link created a bite that was remarkably powerful: 11,000 pounds. 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. And to make matters worst for its prey, the speed at which Dunkleosteus opened its mouth created something that has yet to be produced by any fish of its size again...Suction! When this animal opened its mouth it literally sucked its prey toward its jaws.
The last aspect of this animal that should send shivers down your spine is its teeth, or lack there of. This giant fish didn't have teeth. Instead it had blade like extensions from its skull that would have just barley overlapped when the mouth was closed and would have been EXTREMELY sharp. These are not a series of individual teeth, these are like two giant curved sharp meet cleavers sucking you in and literally cutting you cleaning in half with the second strongest bite force of any oceanic animal in earths history!
The majority of the specimens that have been found consist of only the skull and jaws. So the rest of this animals body must have been made of cartilage like a shark or some other biolinkage. This makes how the rest of its body looked much harder to determine. Scientists use specimens of their closest placoderm relatives to help fill in these blanks.
The result is a 30 foot long prehistoric ocean monster that could bite a large sea turtle in half. Dunkleosteus is one of the most fascinating results of evolutionary experimentation in earths history. There have been many paleo-artists and sculptors that have come up with many different ways of how this animal looked. But they all have one think in common...A terrifying rendition of a prehistoric beast.