Dunkelosteus belongs to the Placodermi, a family of armour-plated fishes. More precisely, it was an arthodire - one of the more advanced members of the placoderm fish.
Dunkelosteus was probably the largest member of the placoderms, and the largest animal up to that time, which would stay that way until the evolution of the dinosaurs. The Placodermi first started appearing in the Silurian, and all of them were extinct by the late Devonian. There are no modern descendants.
Dunkleosteus had one of the most powerful bite of any fish, well ahead of all modern-day sharks, including the Great White shark. Dunkleosteus could concentrate a force of up to 8,000 pounds (3,628 kg) per square inch at the tip of its mouth, effectively placing Dunkleosteus in the league of Tyrannosaurus rex and modern crocodiles as having the most powerful known bite. Dunkleosteus could also open its mouth in one-fiftieth of a second, which would have caused a powerful suction that pulled the prey into its mouth, a food-capture technique reinvented by many of the most advanced teleost fishes today. Due to its heavily armoured nature, Dunkleosteus was likely a relatively slow (albeit powerful) swimmer. By Devonian standards, Dunkleosteus was one of the most highly evolved animals. It was one of the earliest jawed fishes. Instead of actual teeth, Dunkleosteus possessed two long, bony blades that were extensions of its jaw that could slice through flesh and snap and crush bones and almost anything else.
It was a vicious, gluttonous hunter, and probably ate whatever hapless creature it could overpower. The discovery of Dunkleosteus armor with unhealed bite marks strongly suggest that they cannibalized each other when the opportunity arose. Frequently, fossils of Dunkleosteus are found with boluses of fish bones, semi-digested and partially eaten remains of other fish. As a result, the fossil record indicates that it may have routinely regurgitated prey bones rather than digesting them.
Cladoselache did not prey on Dunkleosteus, it was the other way around. It is commonly thought, and commonly said that placoderms, such as Dunkleosteus, were outcompeted by the smaller, swifter fishes, such as the early shark Cladoselache. However, this assessment fails to take into account that predatory placoderms would have inhabited different ecological niches than the early sharks during the Devonian period. As such, claiming that Cladoselache was a more efficient predatory fish than Dunkleosteus because the former was apparently faster than the latter would be akin to saying that the orca is a superior marine predator than the swordfish because orcas have teeth. Dunkleosteus may have also been one of the first animals to internalize egg fertilization, and thus sexually reproduce in the manner that most mammals do today.
Although Placoderms only existed for 50 million years, their mark on the fossil record is quite visible. They were a pioneer in the later scenes of the Paleozoic, and were vital to the success of the vertebrates. The Placoderms died out in the late Devonian for reasons that are still not well understood.
Dunkleosteus remains have been found in late Devonian strata in Morocco, Belgium, Poland, and North America.
- In the Dinotopia books and movies a massive Dunkleosteus guards the underwater entrance to the subterranean caves that contain the strutters and sunstones.
- Dunkleosteus was the fifth most dangerous sea predator in Sea Monsters. The show counted down the top 7 most dangerous sea creatures in history. Dunkleosteus was depicted as being canniballistic and capable of bending metal.
- The Devonian predator also made a brief appearance in the video game ParaWorld.
- In the video game E.V.O. Search For Eden, Dunkleosteus appeared as an enemy creature in the first time period, and the player could evolve its jaws and body, both being the strongest in those categories.
- China Miéville's novel The Scar features Dunkleosteus, where they are also referred to as "bonefish".
- In the dolphin Ecco the Dolphin, Dunkleosteus appeared as an enemy in the prehistoric levels. Ironically the Dunkleosteus existed in the Devonian period and the prehistoric levels takes place 55 million years ago. They were already extinct during that time. Even its echolocation sprite resembles a shark.
- It appears in ARK: Survival Evolved.
- Zack & Wiki features the Dunkleosteus which is called the "Fountain Guardian". The Dunkleosteus had to be fished out to complete a puzzle.
- Dunkleosteus is also featured in the novel Meg:Hell's Aquarium as the first resident of the Dubai aquarium.
- Dunkleosteus appears in the second episode of Animal Armageddon where its extreme hunger drove it to extinction.
- It appears in Jurassic Park: Builder as the first creature in the Aquatic Park.
- Dunkleosteus appears in Jurassic World: The Game as a legendary cave creature in the aquatic park.
- A school of small Dunkleosteus appears in the 2004 film Megalodon where they escape to the surface after the ground they were trapped under collapsed. One of the fish get into the oil rig and attacks a person before getting its head cut off.
- Dunkleosteus also appears in Prehistoric Monsters Revealed where it is despicted having a dorsal fin.
- The shark like monster in Monster Shark is part Dunkleosteus and part octopus.
- Dunkleosteus makes a brief cameo chasing an ammonite in the anime film Age of the Great Dinosaurs.
- A Dunkleosteus makes a cameo in the documentary Sea Rex.