The fossil shows a badger-like creature devouring with its beak a small dinosaur whose skeletons are intertwined. The find comes from a place known as “China’s Pompeii,” where mud and debris from ancient volcanoes buried the creatures in place.
“This appears to be a prehistoric hunt captured like a frozen image in stone,” University of Edinburgh paleontologist Steve Brusatte, who was not involved with the study, said in an email.
The fossil, described Tuesday in Scientific Reports magazine, shows two creatures from around 125 million years ago, the Cretaceous Period.
Although the mammal was much smaller, researchers believe it attacked the dinosaur when both were trapped in the volcanic flow, according to study author Jordan Mallon, a paleobiologist at the Canadian Museum of Nature. The mammal sits atop the dinosaur, its paws clutching the reptile’s jaw and one hind leg while its teeth sink into the rib cage.
“I’ve never seen a fossil like this,” Mallon said.
It had previously been suggested that mammals ate dinosaur meat: another fossil showed that a mammal had died with dinosaur remains in its stomach.
But this new discovery also suggests that mammals may have been hunting dinosaurs many times larger than them, rather than just feeding on already dead dinosaurs, Mallon explained.
“It messes up the old story,” Brusatte said. “We used to think of the age of the dinosaurs as a time when dinosaurs ruled the world and small mammals lurked in the shadows.”
The study’s authors acknowledged that there had been some known false fossil finds in this region of the world, which Mallon called worrisome when they began their research. But after preparing the skeletons himself and analyzing the rock samples, he said they are confident the fossil – discovered by a farmer in 2012 – is real and would like other scientists to examine the fossil.
The mammal in the fossil duo is the carnivorous, house-cat-sized Repenomamus robustus, Mallon said. The dinosaur – Psittacosaurus lujiatunensis – was about the size of a medium-sized dog with a parrot-like beak.
This species was herbivorous, but other dinosaurs were carnivores or ate both. Ultimately, dinosaurs would probably have eaten mammals even more often than vice versa, Mallon said.
“And yet we now know that mammals were at least sometimes able to defend themselves,” he added.