Cretaceous period discovery gives insight into prehistoric life in Alberta
Fossil evidence discovered in southern Alberta suggests a crocodile-like creature bit a flying reptile 76 million years ago, according to a new study published Thursday in the Journal of Paleontology.
Researchers say the new findings provide insight into predator-prey dynamics in the region during the Cretaceous period and mark the first evidence in North America of ancient crocodilians opportunistically feeding on giant prehistoric flying reptiles.
The study was led by researchers from the Royal Tyrrell Museum of Palaeontology in Drumheller, Alta., the University of Reading in the United Kingdom and the University of New England in Australia.
"These azhdarchids are a bit of a mystery," said Dr. Caleb Brown from the Royal Tyrrell Museum and the lead author of the study.
"Any unique little tidbits of information we can put into there, especially when they're of direct evidence, is really key."
The fossilized neck bone of a juvenile pterosaur vertebra was found in Dinosaur Provincial Park, where some of the most important dinosaur fossil discoveries have been made, the researchers said.
According to the study, the neck bone shows "telltale signs" of being bitten by a crocodile-like creature, bearing a circular four-millimetre-wide puncture mark from a crocodilian tooth.
A closeup image of the neck vertebra of cryodrakon boreas. (Royal Tyrrell Museum)
The fossil was unearthed during an international field course led by Brown and Brian Pickles from the University of Reading in July 2023.
"Pterosaur bones are very delicate. So finding fossils where another animal has clearly taken a bite is exceptionally uncommon," Brown said. "This specimen being a juvenile makes it even more rare."
The fossilized neck bone belonged to a young azhdarchid pterosaur, with an estimated wingspan of two metres. An adult azhdarchid pterosaur would have been as tall as a giraffe with a wingspan of about 10 metres, study authors said.
Researchers say the bone was compared with other pterosaur bones as well as analyzed using micro-CT scans to confirm that the puncture mark was an actual bite and not caused during fossilization or excavation.
"We do have evidence, at least one other case, where we have a crocodilian in Europe that is thought to have eaten an azhdarchid, that itself is not a novel occurrence," Brown said.
"It's always great when you have a second specimen that says, 'yeah, this happened the second time,' which is not a one off."
