Paleontologists have launched an investigation into a prehistoric "cold case" after uncovering a rare fossil in Alberta, Canada. The find, a juvenile pterosaur bone with distinctive bite marks, has sparked questions about predator-prey interactions during the Cretaceous period.
Unearthing the Discovery
In July 2023, students from the University of Reading in the UK, led by ecology professor Brian Pickles, participated in a field course at Dinosaur Provincial Park, a UNESCO World Heritage Site in Alberta. While studying prehistoric ecosystems, the team unearthed a small, fossilized vertebra. This discovery, already remarkable due to the fragile nature of pterosaur bones, was further distinguished by an unusual puncture mark on its surface.
The findings, detailed in the peer-reviewed Journal of Paleontology on January 23, 2025, revealed the vertebra belonged to a juvenile Azhdarchid pterosaur—a species of giant flying reptile with bird-like, delicate bones. These creatures soared through the skies 76 million years ago, during the age of dinosaurs.
Clues in the Puncture
Upon closer examination, researchers identified a conical puncture at one end of the bone. Unlike fractures caused by fossilization or recent damage from tools, the puncture bore unique characteristics:
No healing evidence: The absence of remodeling around the hole suggested it occurred at or near the time of the pterosaur's death.
Ancient origin: The cemented material within the puncture confirmed it wasn’t a recent event.
This led researchers to hypothesize the mark was made by the bite of a predator, likely a crocodilian species. The conical teeth and size of such predators aligned with the injury.
Prehistoric Predator and Prey
The juvenile pterosaur, with an approximate wingspan of six feet, may have been an easier target for predators compared to adult Azhdarchids, which could grow to giraffe-like heights and boast wingspans exceeding 30 feet.
“Bite traces like these offer invaluable insights into species interactions from millions of years ago,” explained study author Caleb Brown from the Royal Tyrrell Museum of Paleontology. “Although we can’t determine if the pterosaur was alive when attacked, the fossil provides evidence that crocodilians preyed on or scavenged juvenile pterosaurs in this region.”
This discovery marks the first documented interaction between Azhdarchid pterosaurs and crocodilians in North America, shedding light on the complex dynamics of prehistoric food webs.
A Landmark Finding
Dinosaur Provincial Park, a treasure trove of fossils in southern Alberta, continues to unveil new chapters of Earth’s ancient history. The research team—including Caleb Brown, Brian Pickles, Phil R. Bell, and Holly Owers—has added a crucial piece to the puzzle of life 76 million years ago.
Through the rare find of this fossilized vertebra, scientists have not only reconstructed a moment from the distant past but also expanded our understanding of the intricate relationships between predators and prey in the Cretaceous world.
