Is this fragile jawbone a pterosaur or not? Other researchers also had questions about the fossil, unearthed along with thousands of others during a decades-long archaeological dig at a remote bone bed in the Petrified Forest National Park in Arizona.

The 209-million-year-old fossil offers clues to the evolution of the reptiles, which have more than 150 named species including the well-known pterodactyl.

Paleontologists have uncovered in Arizona a Triassic treasure trove of fossils dating back 209 million years ago.