image: This 14-inch-long Sauropodomorph dinosaur track actually is two footprints in one and was left by a creature that walked on four legs. The imprint includes the deeper central circular portion, which was left when a dinosaur’s "pes" or rear foot, stepped into the larger, shallower print left by a "manus" or front foot. The toe prints, top and upper right, were left by the front foot, obscuring prints from the rear toes. The print is one of many identified by University of Utah scientists at a large dinosaur "trample surface" in the Vermillion Cliffs National Monument in northern Arizona. view more
Credit: Winston Seiler, University of Utah