Paleontologists have uncovered the fossilized jawbone of a newly identified pterosaur species, along with a multitude of fossils, including one of the world’s oldest turtles, in a secluded bone bed located within Petrified Forest National Park in Arizona, USA.
Artist Reconstruction of Eotephradactylus chintireae, along with other animals and plants preserved in the bone beds of Petrified Forest National Park, Arizona, USA. Image credit: Brian Eng.
The newly discovered pterosaur species, Eotephradactylus chintireae, existed in what is now Arizona during the late Triassic period, approximately 209 million years ago.
“The winged reptile was small enough to comfortably perch on a person’s shoulder,” stated Dr. Ben Krigman from the Smithsonian Institution’s National Museum of Natural History.
“One of the most exciting aspects of this discovery was that the teeth remained intact in the bones, making the identification of these animals significantly easier,” added Suzanne McIntier, a volunteer preparer who dedicated 18 years at Fossil Lab at the National Museum of Natural History.
“The teeth-filled jaws provided crucial insights into the lifestyle of the earliest pterosaurs.”
“The worn tips of the teeth suggest a high likelihood that they consumed armored fish and other prey,” she explained.
Eotephradactylus chintireae coexisted with large amphibians, armored crocodile ancestors, frogs, and turtles.
In addition to this flying reptile, paleontologists have found over 1,200 individual fossils, which include bones, teeth, fish scales, and coprolites.
“This collection represents 16 different vertebrate groups that previously inhabited diverse ecosystems,” they noted.
“The braided rivers in this region were teeming with fish, such as freshwater sharks, coelacanths, and ancient amphibians.
The surrounding environment was also home to some of the formidable reptiles that evolved during the early Triassic, including giant alligator-like armored herbivores and predatory creatures.”
The newly identified bone bed is part of the Upper Sinru Formation in Petrified Forest National Park.
“This area of northeastern Arizona was situated in the heart of Pangaea on the supercontinent, positioned just above the equator 209 million years ago,” the researchers added.
“The semi-arid landscape was interspersed with small river channels, which were prone to seasonal flooding. These floods deposited sediment and volcanic ash into the channels.”
“One of these floods might have buried creatures that remain in the bone beds. The site is rich in small fossils, making it impossible to excavate all of them in the field.”
The research team believes the new site will help bridge gaps in the fossil record prior to the final extinction event (ETE).
“About 1.5 million years ago, volcanic eruptions linked to the fragmentation of Pangaea drastically altered the world’s climate and led to the extinction of approximately 75% of Earth’s species,” the scientists commented.
“This opened the door for new groups, such as dinosaurs, to emerge and thrive in ecosystems globally.”
“Due to the lack of fossil outcrops from just before the ETE, it is challenging to find direct evidence of this transition on land.”
“This site captures the shift toward a more modern terrestrial vertebrate community, marking the beginning of the flourishing of groups following the Mesozoic era, alongside these older species that survived into the Triassic period.”
“Such fossil beds provide evidence that all these animals coexisted.”
The team’s study was published in Proceedings of the National Academy of Sciences.
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Ben T. Krigman et al. 2025. The extraordinary bone bed uncovers a vertebrate community with pterygoids and turtles in the equatorial Pangaea prior to terminal extinction. PNAS 122 (29): E2505513122; doi: 10.1073/pnas.2505513122
Source: www.sci.news
