‘Ash-winged dawn goddess’ fossil unearthed in Arizona

An artist’s reconstruction of the fossilized landscape, plants and animals found preserved in a remote bonebed in Petrified Forest National Park in Arizona. (Illustration by Brian Engh)

A team led by the Smithsonian has discovered North America’s oldest known pterosaur—a small, seagull-sized flying reptile that lived more than 200 million years ago in what is now Arizona.

According to the report published in Proceedings of the National Academy of Sciences, the fossil was found in a remote part of Petrified Forest National Park. It includes part of the animal’s jaw and a wing bone, dating back to nearly 209 million years ago, making it the earliest known pterosaur from the continent.

“There are two other Triassic pterosaur fossils from the North American continent, one from Greenland and one from Utah, but they’re both younger than the one we found,” Ben Kligman, the study’s lead author and a postdoctoral fellow at the Smithsonian’s National Museum of Natural History, said in a video interview with CTVNews.ca.

The new species is named Eotephradactylus mcintireae, meaning “ash-winged dawn goddess,” referring to the volcanic ash that helped preserve it in an ancient riverbed.

“The animal itself would have been the size of a small seagull, so it could have sat on your shoulder,” Kligman said adding that it likely fed on armoured fish in the river system it once flew over.

“The teeth in the jaw of this pterosaur … all are worn down,” he explained. “It means that this pterosaur was eating something with a hard skeleton or hard bony parts, and the fish that were living in this river system … would be covered by an armoured skin.”

The find sheds light on a time just before a mass extinction wiped out three-quarters of the world’s species and set the stage for dinosaurs to dominate.

The fossil was uncovered with more than 1,200 other specimens, including bones from ancient amphibians, one of the world’s oldest turtles and a crocodile relative.

Most early pterosaur fossils have been found in Europe and are flattened by pressure from layers of ocean sediment, but the Arizona discovery was preserved in three dimensions, allowing scientists to study fine details like tooth placement and replacement teeth growing inside the jaw.

“(They are) animals that could fly, so their bones are oftentimes hollow, and they are difficult to collect,” Kligman said. “If you have a tiny two-centimetres-long little hollow bone, it’s really easy for it to break apart … and it’s hard to even recognize the fossil.”

Kligman says similar fossils are likely across the world because pterosaurs could fly, so they didn’t have barriers to their dispersal.

He hopes the modern scanning techniques that his team used can open the door for more discoveries in similar riverbed deposits.

“We’re hoping through showing a methodology for finding, collecting, preparing and then CT scanning these bones, (we can) open a pathway for us and other researchers to reexamine these Triassic river deposits and hopefully find more pterosaurs.”