Scientists have found ancient nail tooth shark fossils deep inside Mammoth Cave in Kentucky, revealing new information about ...

A tiny shark species dating back hundreds of millions of years has been identified at Mammoth Cave National Park in Kentucky, the National Park Service said.

For the past several years, Maisey and colleagues have investigated a Doliodus problematicus fossil discovered in 2003, and hailed as the world’s oldest shark fossil. The team investigated the ...