Paleontologists have unearthed the fossilized jawbone of a new pterosaur species alongside hundreds of other fossils — including one of the world’s oldest turtles — at a remote bonebed in Petrified Forest National Park in Arizona, the United States.
An artist’s reconstruction of Eotephradactylus mcintireae, other animals, and plants found preserved in a remote bonebed in Petrified Forest National Park in Arizona, the United States. Image credit: Brian Engh.
The newly-identified pterosaur species, Eotephradactylus mcintireae, lived in what is now Arizona during the Late Triassic epoch, some 209 million years ago.
“The winged reptile would have been small enough to comfortably perch on a person’s shoulder,” said Dr. Ben Kligman from Smithsonian Institution’s National Museum of Natural History and his colleagues.
“What was exciting about uncovering this specimen was that the teeth were still in the bone, so I knew the animal would be much easier to identify,” added Suzanne McIntire, a preparator who volunteered in the National Museum of Natural History’s FossiLab for 18 years.
“The tooth-studded jaw revealed crucial clues about how the earliest pterosaurs lived.”
“Because the tips of the teeth were worn down, we concluded that the pterosaur likely fed on the site’s fish, many of which were encased in armor-like scales.”
Eotephradactylus mcintireae co-existed with giant amphibians, armored crocodile relatives, frogs and turtles.
In addition to the flying reptile, the paleontologists uncovered more than 1,200 individual fossils, including bones, teeth, fish scales and coprolites.
“This assemblage contains 16 different groups of vertebrate animals that once inhabited a diverse ecosystem,” they said.
“The region’s braided rivers were filled with fish, like freshwater sharks and coelacanths, as well as ancient amphibians, some of which grew up to 1.8 m (6 feet) long.”
“The surrounding environment was home to fearsome reptiles that evolved earlier in the Triassic, including armored herbivores and toothy predators that resembled giant crocodiles.”
The newly-discovered bonebed is part of the upper Chinle Formation at Petrified Forest National Park.
“This part of northeastern Arizona was positioned in the middle of the supercontinent Pangea and sat just above the equator 209 million years ago,” the researchers said.
“The area’s semi-arid environment was crisscrossed by small river channels and likely prone to seasonal floods. These floods washed sediment and volcanic ash into the channels.”
“One of these floods likely buried the creatures preserved in the bonebed. The site is so rich in small fossils that excavating them all in the field was impossible.”
According to the team, the new site helps fill in a gap in the fossil record that predates the end-Triassic extinction (ETE).
“Around 201.5 million years ago, volcanic eruptions associated with the break-up of the supercontinent Pangea dramatically altered global climates and wiped out roughly 75% of the species on Earth,” the scientists said.
“This cleared the way for newer groups, like dinosaurs, to diversify and dominate ecosystems worldwide.”
“Direct evidence of this transition on land is difficult to find due to a lack of terrestrial fossil outcrops from right before the ETE.”
“The site captures the transition to more modern terrestrial vertebrate communities where we start seeing groups that thrive later in the Mesozoic living alongside these older animals that don’t make it past the Triassic.”
“Fossil beds like this enable us to establish that all of these animals actually lived together.”
The team’s paper was published in the Proceedings of the National Academy of Sciences.
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Ben T. Kligman et al. 2025. Unusual bone bed reveals a vertebrate community with pterosaurs and turtles in equatorial Pangaea before the end-Triassic extinction. PNAS 122 (29): e2505513122; doi: 10.1073/pnas.2505513122
