Produced by the Population Genetics and Evolution class, Furman University

The Devonian: Dunkleosteus
Dunkleosteus were massive predatory fish that ruled the Devonian oceans. They are classified as Placoderms because of the hard plates that covered the surface of the head. The rest of their body, however, lacked these plates to allow for greater flexibility when swimming after prey (CMNH 2010). Discovered fossils lead scientists to believe that Dunkleosteus could have reached over twenty feet in length, meaning that it was probably the largest organism in the ocean at the time (AMNH 2010). The most interesting feature that they had was their massive, jawed mouth. Their jaws were not lined with teeth; rather, their jaw had a set of paired razor sharp plates (White 2010). Dunkleosteus fossils demonstrate that, with the evolution of jaws, vertebrates came to dominate the top-predator niche in the oceans. Jaws allowed fish to close their mouth with greater force, allowing fish to colonize the adaptive niche of 'predator'. Few have ever been as fearsome as Dunkleosteus!

Page by Pete Calomiris

Picture 1: Dunkleosteus fossil. From: Associated Content
Picture 2: Dunkleosteus painting, from:
Prehistorics Illustrated

American Museum of Natural History. 2010. Dunkleosteus. Accessed February 2010.

The Cleveland Museum of Natural History. 2010. Dunkleosteus telleri. Accessed February 2010.

White AT. 2003. Dunkleosteus telleri. Accessed February 2010.