The work of a paleontologist is often like solving a puzzle with no picture on the box and most of the pieces missing. From scattered bones and teeth, scientists studying fossils extrapolate entire long-dead creatures, and even relationships between different species. But every now and then, researchers get a lucky break in the form of nearly complete skeletons, their bodies preserved in a way that offers a glimpse into their behavior in life.
This could be the case with a recently described fossil of a badger-like mammal and a Labrador retriever-sized dinosaur, locked in what appears to be an eternal tussle. A mixed team of Canadian and Chinese researchers published their findings in the journal Scientific Reports on Tuesday, along with a section of the study devoted to addressing concerns that the fossil is a fake.
The prehistoric skirmish took place about 125 million years ago in what is now northeastern China, and appears to be something of a dinosaur-era man-bites-dog story. Usually in that period, according to conventional wisdom, mammals were gentle, eking out a tenuous existence as terrifying reptiles shook the earth around them. But the unlikely fossil depicts a battle between a mammal called Repenomamus robustus and a bipedal, plant-eating relative of Triceratops called Psittacosaurus lujiatunensis.
Size-wise, the dinosaur had an advantage, but Repenomamus, preserved with its teeth stuck into the ribcage of Psittacosaurus, seems to have punched above its weight. The dinosaur’s bones show no signs of being gnawed by scavengers, indicating that the Repenomamus encounter occurred when the Psittacosaurus was still alive.
“There are examples today of small carnivorous mammals taking down much, much larger prey,” said Jordan Mallon, a paleontologist at the Canadian Museum of Nature and co-author of the study. He showed wolverines taking down a caribou. He added, “We think that Repenomamus was probably a similarly small, feisty predator that was willing to take down prey much larger than itself if it had to.”
Keeping the animals meso-manala required a great deal of luck (or bad luck, from the animals’ point of view). It started with a volcanic eruption, releasing ash. This ash could have been converted into a landslide by seasonal flooding or heavy rains. Then, while this Repenomamus and Psittacosaurus were fighting, “this mudflow kind of caught them off guard and preserved them for 125 million years,” Dr. Mallon said.
The fossil was discovered in 2012 by farmers in the Chinese province of Liaoning and obtained by Gang Han of the Hainan University of Science and Technology, co-author of the study. The find was incredible, and there are many cases when such discoveries turned out to be too good to be true. Fossil fakes, including separate specimens put together to complete a skeleton or scene, are a “big problem”, Dr Mallon said. “This was a concern that we had, and so we had to do our homework to at least convince ourselves” that it was legitimate.
Dr Mallon said the researchers dug into the rock surrounding the fossils and found that the mammal’s left lower jaw “had plunged into the rock and actually bit the dinosaur’s ribs”, rather than simply being put together by a fossil forger. . . The researchers also analyzed the rock in the fossil and rock from the fossil beds where it was reportedly found; they matched. Based on this independent evidence, “we feel pretty satisfied that this is a genuine fossil and it’s not a fake,” Dr. Mallon said.
Or if it’s a fake, he said, it’s “the best I’ve ever seen.”
David Grossnickle, an evolutionary biologist at the University of Washington, who was also not involved with the study, said that while in the “worst case scenario,” parts of the fossil specimen may have been forged, the mammal skull biting into the bone of a dinosaur. appears to be real, and that piece alone is “still an incredible fossil.”
If no convincing challenge to its authenticity is presented, the fossil offers tantalizing evidence of how mammals and dinosaurs interacted.
“We rely on spectacular fossils like this to really fill in the gaps of how these ancient ecosystems functioned, because we can’t always rely on the bones alone to tell us these stories,” Dr. Mallon said.
Michael Pittman, a paleontologist at the Chinese University of Hong Kong who was not involved with the study said that the immortalized bite did not necessarily mean that Repenomamus hunted dinosaurs for food and that the animals may have engaged in less of a predator. removal and more “battle”.
But the study may contribute to the “growing evidence that Mesozoic mammals were more ecologically diverse than we classically thought,” Dr. Grossnickle said, “and get some revenge, I guess, on those big bad dinosaurs.”