Giant, swimming mouths: Oral dimensions of extant sharks do not accurately predict body size in Dunkleosteus terrelli

A new study by Case Western Reserve University Ph.D. student Russell Engelman published in PeerJ attempts to address a persistent problem in paleontology—what were the size of Dunkleosteus and other late Devonian arthrodire placoderms. Arthrodire placoderms are extinct fishes that had armor covering their head and part of their torso, but like sharks the rest of their skeleton was made of cartilage, meaning most of their body did not preserve when they became fossilized.