STEPHEN J. KRASEMANN / SCIENCE PHOTO LIBRARY STEPHEN J. KRASEMANN / SCIENCE PHOTO LIBRARY
Devonian Fish (Dunkleosteus) skull. Dunkleosteus measured up to 10 meters long and was the largest animal in the Devonian seas. Massive bony plates protected its head; a hinge at the back of its skull allowed the head to rise and the jaws to lower, giving it an enormously powerful bite. What appear to be teeth are actually sharp, bony plates at the front of its jaw. Royal Tyrrell Museum, Drumheller, Alberta, Canada.
Model release not required. Property release not available.