This 'ash-winged dawn goddess' is North America's newest pterosaur

Paleontologists searching the ancient rock of Petrified Forest National Park, Arizona, have uncovered an exceptional bonebed. Dating to 209 million years ago, the Triassic trove includes nearly 1,500 fossils from fish, frogs, turtles, crocodile-like predators, and more. Most remarkable of all, it yielded fossilized remains from the oldest pterosaur yet found in North America: Eotephradactylus mcintireae, or the “ash-winged dawn goddess.”

Early pterosaurs are notoriously difficult to find. The flying reptiles took to the air thanks to leathery wings of skin stretched between their bodies and an extremely elongated fourth finger. Their small size and hollow bones made flight easier but also meant their skeletons were often destroyed before fossilization could occur. The discovery of a jaw, a wing bone, and a tooth belonging to an early pterosaur is a windfall for paleontologists.

“This would be the last place you would expect to find pterosaur bones,” says Ben Kligman, a paleontologist at the Smithsonian’s National Museum of Natural History and one of the researchers who made the find. Back when this seagull-sized reptile was flapping over what’s now eastern Arizona, the area was a floodplain crossed by flowing channels. “Sediment carried by the channel’s flow had preserved the delicate bones,” he says.

Kay Behrensmeyer, curator of vertebrate paleontology at the Smithsonian’s National Museum of Natural History, in Petrified Forest National Park documenting the geology of a bonebed in 2023. Photograph by Ben Kligman, Smithsonian

Kligman and his colleagues named the new flier “ash-winged dawn goddess” for the volcanic ash at the fossil site that allowed geologists to precisely date the bonebed and because it represents an early entry in pterosaur evolution. They also honored museum preparator Suzanne McIntire, who first uncovered the pterosaur’s tiny bones. The team published their finds Monday in the journal Proceedings of the National Academy of Sciences.

Based on worn-down teeth in the pterosaur’s jaw, Kligman and his colleagues propose it preyed on the abundant scaly fish found in the prehistoric channels. The paleontologists suggest there may be more Eotephradactylus bones from ancient channel deposits hiding in similar Triassic rocks elsewhere in the world. The streams that provided pterosaurs with fish and other morsels had a better chance of preserving their bones, outlining the story of how the flying reptiles first spread around the planet.

Holotype jaw of Eotephradactylus mcintireae, the new species of pterosaur. Scale bar in cm. Photograph by Suzanne McIntire

Revealing all the species in the bonebed, including Eotephradactylus, was painstaking work that took about a decade, says Kligman. There, they also unearthed bones of armadillo-like crocodile relatives called aetosaurs, large predatory super salamanders called metoposaurs, a dragon-like reptile covered in large scales called Vancleavea, and early turtles with thin shells and spikes on their necks.

“What’s so interesting about the community,” says Kligman, “is that it includes animals that would go on to dominate post-Triassic ecosystems, like frogs, turtles, and pterosaurs, living alongside archaic groups that would soon go extinct in a mass extinction.”