That is a Dunkleosteus, a giant armored fish.
— Allen, about Dunkleosteus

Dunkleosteus ("Dunkle's Bones") was a large, predatory placoderm, or heavily armored fish, from the Devonian that lived roughly 380-360 million years ago. This carnivorous fish was the largest and top predator in its ecosystem in the Devonian seas.



Dunkleosteus lived during the Late Devonian period from 380 to 360 million years ago, living alongside animals like Stethacanthus, Hyneria, and even other armored-plated fish. It was the apex predator in the Devonian Seas. After thriving more than 50 million years, the entire class of placoderms, Dunkleosteus included, disappeared.



Dunkleosteus was the largest predator of its time. It was a real leviathan that measured over 30 feet (9 m) in length and could have weighed at least 4 to 5 tons, as much as two or three elephants.

Dunkleosteus was a massive animal. It had a thick and withstanding armour plated head. The rest of its body was bare flesh. Its jaws were powerful and were lined with teeth-like bony plates which were used to shear off chunks of meat and to crush bone. Dunkleosteus also had large, blue eyes.

Dunkleosteus had two pairs of large and powerful fins. On its back was a short albeit long-running dorsal fin.


The fearsome head of Dunkleosteus

These creatures had a fearsome head, which also shows the classic features of Dunkleosteus. They had very thick and protective armor plating on the front of their bodies on the heads, up to over two inches thick and only the first half of their bodies were covered with that.

Additionally, it was also what was in its mouth thats scary. Rather than having teeth, Dunkleosteus instead had extensions of the jaw bones. They were for shearing prey and these animals have to punch through other armored fish and those jaws were backed up by powerful mussels at the back of the neck. They had these massive jaws with big sharp shears sticking out. They slice them together, like scissors working, the action of slicing them together keeps them sharp and with that, they can cut through anything.


Dunkleosteus was a solitary but titanic predator, the largest predator in the Devonian in fact. What made it so powerful were its protective armor plating and its powerful jaws which contained several, teeth-like bony plates. These plates were used to grind and shear off pieces of flesh.

Because of its strong jaws, Dunkleosteus could bite through armour plating as strong as chainmail. However, they couldn't digest those parts and would regurgitate the plates as well as any other inedible parts of its prey's anatomy. So Dunkleosteus, similar to modern day anaconda's, spit up their food.


Dunkleosteus spitting out its food

It was normal behavior. Dunkleosteus wasn't being sick. But a fish like this that feeds on armored food needs to get rid of the indigestible bits and it's perfectly normal...for 360 million years ago.

Dunkleosteus eating its own kind

Due to the other lethal competition in the Devonian seas, Dunkleosteus would kill anything that got in its way. This even included its own kind, even it it was just a little Dunkleosteus. As a result, Dunkleosteus were not just predators, they were often cannibalistic as well.

Journal EntryEdit

A giant, armored plated fish of the Devonian Era, this was a real leviathan with skin up to over 2 inches thick. Measuring over 30 feet long and weighing 4-5 tons, Dunkleosteus were the apex predators of the Devonian seas, over 360 Million years ago. When looking at is fearsome head, which itself shows classical features of Dunkleosteus, it appears that this armored-plated fish didn't have any teeth, but instead had extensions of its jaw bones.

With these jaw bones, these sea predators could use them to sheer through even other armored fish. However, when they eat armored fish, Dunkleosteus would spit up its food. As it appears, it's quite normal behavior. Instead of being sick, these predators had to spit of the parts of their food that were indigestible. Surprisingly, these fish also happen to be not only predators, but cannibals as well, eating even little Dunkleosteus.

— Allen, in his Journal, about Dunkleosteus