"I bent down to take a closer look, and to my shock, I realized it was a shark tooth," Phillipe said. "At first, my neighbor thought I was pulling a prank on him, but there it was in my hand—no ...

A rendering of Clavusodens mcginnisi, or “McGinnis’ nail tooth,” an ancient shark that stalked the ocean floor 340 million years ago. Rendering courtesy of the National Park Service A shark ...