Rare Neck Fossil With Puncture Mark Suggests a Prehistoric Crocodilian Snacked on a Young Pterosaur 76 Million Years Ago
The fossil sheds light on interactions within the Cretaceous food web and may represent the first record of this type of predation in North America
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76 million years ago, a young pterosaur might have had a very bad day. A bite hole in a rare neck bone fossil discovered in Canada suggests a crocodile-like predator chomped on the flying reptile, either in a deadly attack or a post-mortem scavenged snack. As detailed in a study published late last month in the Journal of Paleontology, the fossil sheds light on animal dynamics during the Cretaceous Period.
Pterosaurs were flying reptiles that lived alongside dinosaurs, dominating the skies throughout the Mesozoic Era (66 million to 252.2 million years ago). They were the first vertebrates on the planet to take flight. But such a well-preserved pterosaur fossil was shocking to researchers.
“Pterosaur bones are very delicate—so finding fossils where another animal has clearly taken a bite is exceptionally uncommon. This specimen being a juvenile makes it even more rare,” lead author Caleb Brown, a paleontologist from the Royal Tyrrell Museum of Paleontology in Canada, says in a statement.
Paleontologists discovered the bone in Alberta’s Dinosaur Provincial Park, a UNESCO World Heritage site famous for its fossil beds, during an international field course in July 2023 that included students from England’s University of Reading.
Researchers identified the fossil as a vertebra of Cryodrakon boreas, a species first discovered in 2019 thanks to another find in the Dinosaur Provincial Park, per Discover magazine’s Monica Cull.
With an adult wingspan of up to 33 feet and a giraffe-like height, the species is one of the largest pterosaurs known to scientists. The young individual to whom this vertebra belonged, however, had an estimated wingspan of “only” around 6.6 feet.
Once the researchers catalogued the fossil, they discovered a round puncture roughly 0.16 inches wide. After further analyses, including micro-CT scans and comparisons with other pterosaur fossils, they suggest the hole was probably a bite mark from a prehistoric crocodile ancestor, though it might have been made by a different carnivore, such as Eodelphis, an early mammal, per another statement. They ruled out dinosaurs as potential culprits, given that those predators’ blade-like teeth didn’t match the shape of the hole.
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If the mark represents a predatory attack, it was a successful one—there was no evidence of a healing process on the bone. But it remains possible that the biter scavenged the body after the pterosaur died of other causes. Cretaceous crocodilians “probably grabbed whatever the hell they’re able to get their mouth around,” David Hone, a paleontologist at Queen Mary University of London who was not involved in the study, tells the New York Times’ Freda Kreier. “It’s what crocs do.”
Ultimately, “bite traces help to document species interactions from this period,” study co-author Brian Pickles, a paleontologist from the University of Reading who led the field course that found the fossil, says in a statement. “We can’t say if the pterosaur was alive or dead when it was bitten, but the specimen shows that crocodilians occasionally preyed on, or scavenged, juvenile pterosaurs in prehistoric Alberta over 70 million years ago.”
If a crocodilian predator really is the culprit behind the bite mark, that would also make the pterosaur neck bone the first evidence from North America of these creatures opportunistically preying on pterosaurs.
