About 315 million years ago — long before dinosaurs roamed the Earth — an early reptile scuttled along in a strangely sideways jaunt, leaving its tiny footprints embedded in the landscape, new research finds.
It's anyone's guess why this ancient, clawed critter walked sideways (although experts have several ideas), but one thing is certain: The animal's prints represent the oldest-known vertebrate track marks ever discovered in Grand Canyon National Park, said Stephen Rowland, a professor of geology at the University of Nevada, Las Vegas, who is studying the fossilized trackway...