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.

At a remote bone bed in Arizona, dense with fossils dating back around 209 million years, a Smithsonian-led team of researchers has discovered North America’s oldest known pterosaur, according to a news release.