Dunkleosteus, a 14‑foot armored fish from about 360 million years ago, lacked true teeth but had razor‑sharp bony plates that sliced flesh and crushed bone. Researchers used 3‑D models of five flattened specimens from Cleveland to reconstruct skulls, jaws, and muscle attachments, revealing shark‑like jaw mechanics and a more cartilaginous skull than previously thought. These findings challenge the suction‑feeding hypothesis and support comparisons to ram‑feeding predators that dismember large prey.
Dunkleosteus — The 14‑Foot Armored Predator with No Teeth but a Bone‑Crushing Bite
Dunkleosteus, a 14‑foot armored fish from about 360 million years ago, lacked true teeth but had razor‑sharp bony plates that sliced flesh and crushed bone. Researchers used 3‑D models of five flattened specimens from Cleveland to reconstruct skulls, jaws, and muscle attachments, revealing shark‑like jaw mechanics and a more cartilaginous skull than previously thought. These findings challenge the suction‑feeding hypothesis and support comparisons to ram‑feeding predators that dismember large prey.
07:05 AM, 11/21/2025Science
About 360 million years ago, a formidable armored fish prowled shallow seas worldwide. Known as Dunkleosteus, this shark-like arthrodire could reach roughly 14 feet (4.3 m) and tear enormous chunks of flesh from its prey. New 3-D reconstructions of multiple specimens reveal a surprising detail: Dunkleosteus did not have conventional teeth, but razor-sharp bony plates that functioned like cleavers.
Background
Fossils of Dunkleosteus have fascinated scientists and enthusiasts since the 1860s. As one of the largest members of the extinct arthrodires, the species Dunkleosteus terrelli has been studied for decades, but many aspects of its skull and feeding behavior remained unclear until recently.
Study and methods
A team led by Russell Engelman of Case Western Reserve University examined the largest known collection of Dunkleosteus fossils at the Cleveland Museum of Natural History. They focused on five nearly complete, flattened skeletons of juvenile and adult individuals and used 3-D modeling to reconstruct skulls, jaws, and muscle attachments that are otherwise obscured by fossil compression.
The last major detailed study of Dunkleosteus jaw anatomy dated to 1932, when arthrodire anatomy was not well understood — Russell Engelman, lead author.
Key findings
Rather than true teeth, Dunkleosteus possessed large, bladed bony plates arranged in the mouth and on the jaws. These structures acted like shearing knives and crushing surfaces capable of slicing flesh and breaking bone. The reconstructions also indicate jaw musculature more similar to sharks and a skull with more cartilaginous components than previously appreciated. Together these features suggest a powerful, rapid bite rather than a suction-based feeding strategy.
Previous proposals had suggested Dunkleosteus used suction to capture prey. However, suction feeders typically bear specialized teeth to hold struggling prey — features absent in Dunkleosteus. Instead, its tusk- and cleaver-like oral plates resemble adaptations seen in modern ram-feeding fishes (for example, gar and some herrings) and terrestrial predators that chop and dismember prey (for example, hyenas and big cats).
Implications
These results refine our understanding of Dunkleosteus’s role as an apex predator of the Devonian seas. Its bone-cutting jaw apparatus would have allowed it to take enormous, decisive bites from large animals, an evolutionary pathway that supports hunting progressively larger prey. The new anatomical detail also means researchers must reassess estimates of bite force and feeding mechanics for this iconic fish.
Although it lacked conventional teeth, Dunkleosteus remained a fearsome, highly effective predator of its time.