An approximately 300 million-year-old fossil skeleton discovered at Canyonlands National Park in Utah could be the first of its kind, researchers say. © Adam Marsh/National Park Service The fossil discovery at Canyonlands National Park was a rare intact skeleton. The exact species and classification have yet to be determined, but the fossil is a tetrapod -- meaning animal with four legs -- and could be an early ancestor of either reptiles or mammals. Paleontologists have determined the fossil could be anywhere from 295 million to 305 million years old, between the Pennsylvanian and the Permian geologic time periods.
