Researchers, volunteers uncover North America’s oldest known pterosaur

(CN) — In the heart of Washington, D.C., a team of volunteers chiseling away at large pieces of sediment pulled from the backcountry of Arizona’s Petrified Forest National Park discovered North America’s oldest known pterosaur, according to a study published on Monday. 

While it’s known for its petrified fossilized wood, as the name would suggest, the Petrified Forest National Park is also home to a unique geological formation called the Owl Rock Member. The area consists of colorful mudstones left behind after inland lakes evaporated. Because the area is so remote, very few scientific studies have been done around it.  

In 2011, a team of paleontologists trekked out to the area and found a bed of fossilized bones from the Triassic ecosystem in the area. Radioisotope dating revealed the area around the bones to be 209 million years old.     

In 2018, Ben Kligman, a Peter Buck Postdoctoral Fellow at the Smithsonian’s National Museum of Natural History and the lead author of the study published in Proceedings of the National Academy of Sciences, began working on the site. 

Kligman and a team uncovered more than 1,200 fossils, including bones, fish scales and even coprolites, or fossilized poop. They also sent large pieces of sediment from the site to the National Museum of Natural History’s FossiLab, where teams of volunteers spent thousands of hours chiseling away rock to reveal fossils. 

Some of those fossils uncovered by volunteers included one of the world’s oldest turtle fossils and a jawbone of a new species of pterosaur, a sea gull-sized winged reptile that lived alongside dinosaurs and was the first vertebrate to evolve powered flight, according to a press release for the study. 

The pterosaur was dubbed “Eotephradactylus mcintireae” after the volunteer who discovered it in a piece of sediment, Suzanne McIntire.

“The pterosaur and turtle, as well as all the other fossils and species described in our study were collected from a single bonebed that has been radioisotopically dating dated to be deposited 209 million years ago. This bonebed has yielded 16 vertebrate species that would have been living in and around a river channel where the bones accumulated. These 16 species would have lived and interacted together in the same community and ecosystem. In this vertebrate community, there are early members of groups that would dominate post-Triassic ecosystems like frogs, pterosaurs, and turtles, but these groups were living alongside archaic groups that would soon go extinct in the end-Triassic Extinction 201 million years ago,” Kligman wrote in an email. “Our study shows that vertebrate communities resembling those previously known only from the Jurassic-onwards were actually present at least 7 million years prior to the end Triassic Extinction. In short, our findings suggest that modern vertebrate communities were first assembling before the end-Triassic extinction, not after it.”

During the breakup of the supercontinent Pangea and associated volcanic eruptions around 201.5 million years ago, some 75% of Earth’s species were wiped out, clearing the way for newer species like dinosaurs to diversify and dominate the Earth, a press release for the study states. 

Evidence of this is difficult to find in the fossil record because of a lack of fossil outcrops. 

The discovery of these specimens helps fill that gap in the fossil record.  

“We know very little about the effects of this extinction on life that was living on land, and we have a much better understanding of what happened at this extinction for life in the oceans. This is because we have a very scant fossil record of life on land immediately before and after the extinction event. Therefore, my current mission is to discover and collect new fossil sites that fill gaps in the fossil record of life on land immediately before and after the end-Triassic extinction event 201 million years ago,” Kligman wrote.