A fossil of the first type of mammal and dinosaur from about 125 million years ago “locked in death” challenges the idea that dinosaurs ruled the land, researchers wrote in a study published Tuesday.
The new fossil, discovered on May 16, 2012, in China’s Liaoning Province, shows a mammal attacking a dinosaur about three times its size. The obvious aggressor was the mammal, carnivorous Repenomamus robustus, researchers wrote in the journal Scientific Reports.
“The mammal died by biting two left dorsal ribs of the dinosaur; its mandible falls down into the induction sediment to firmly strike the bones,” the study’s authors wrote.
The discovery of the two creatures is among the first evidence of actual predatory behavior by a mammal on a dinosaur, Dr. Jordan Mallon, a paleontologist with the Canadian Museum of Nature and co-author of the study, said in a press release.
Repenomamus robustus is a badger-like animal that was among the largest mammals that lived during the Cretaceous period.
The dinosaur was identified as Psittacosaurus, a herbivore about the size of a large dog.
Paleontologists previously believed that Repenomamus preyed on dinosaurs because of fossilized bones found in the stomach of the mammal.
“The coexistence of these two animals is not new, but what is new to science through this amazing fossil is the predatory behavior it shows,” said Mallon.
Experts believe that the attack was preserved when the two animals were caught in a volcanic flow. The area where the fossil was found is known as the “Pompeii of China” because of the many animal fossils buried in a mass of mudslides and debris after one or more volcanic eruptions.
After the discovery, scientists worked to confirm that the fossil was not a forgery. The researchers said that the embedded skeletons and the completeness of the skeletons indicate that the discovery is legitimate and that the animals were not transported before burial.
Steve Brusatte, a paleontologist at the University of Edinburgh who was not involved in the research, tweeted about the discovery, suggesting it was like Wile E. Coyote catching the rover. He said the discovery “turned the old story of dinosaur dominance on its head.”