Dunkleosteus was a predatory placoderm fish from the Late Devonian period. Size estimates put it between 6 and 10 meters (20 and 30 feet) in length. At this size, it was the Apex predator of its sea. Although Titanichthys was larger than Dunkleosteus, Titanichthys was much less powerful because of its smaller jaw. Scientists think that Dunkleosteus had the most powerful bite of any non-chondrichthyan fish, roughly 4,000 kg per square inch. This would be even stronger than Rhizodus. The bite of Dunkleosteus may have been two times more powerful than that of Tyrannosaurus rex, the dinosaur that had the most powerful bite of any land animal.
Dunkleosteus was also incredibly armored, having enough protection to be impervious to every fish besides another Dunkleosteus. Dunkleosteus had a huge amount of armor around its head, although it did lack some around the rest of the fish.