Stupendously Preserved Fossil Shows Mammal Preying on Beaked Dinosaur

About 125 million years ago, a young mammal the size of an opossum bit almost three billed dinosaurs in the side times its size. The animals thus died, entangled and divided with one another, a fossilized tableau of the power shift between dinosaurs and mammals that would eventually occur some 60 million years later.

These are the certainties about the exchange in the Cretaceous until this week, a team of paleontologists unveiled the stunning fossil in a publication published in scientific reports.

The ancient creatures were a Repenomamus robustusa carnivorous mammal, and a Psittacosaurus lujiatunensis, a two-legged, beaked dinosaur that looks like a cross between a parrot and a lizard (which is also the literal meaning of its name). The R. robustus is almost complete, only missing the tip of the tail and is 18.39 inches (46.7 inches) tall cm) long. The Psittacosaurus is 47.1 inches (119.6 cm) long.

“Dinosaurs were almost invariably larger than mammals,” Jordan Mallon, a paleobiologist at the Canadian Museum of Nature in Ottawa and a co-author of the study, said in an email to Gizmodo. “So the working assumption was that the interactions between dinosaurs and mammals were one-way, meaning that the larger dinosaurs always ate the smaller mammals.”

“This new fossil shows that these ancient food webs were a little more complete than we would otherwise have thought, and that mammals were occasionally able to eat even near-adult dinosaurs,” he added.

The dainty hand of the repenomamus in the jaw of the psittacosaurus.

The dainty hand of the repenomamus in the jaw of the psittacosaurus.
photo: Gang Han

Mallon’s team believes the two animals died in the midst of the conflict when a volcanic mudflow engulfed themkilled the creatures and buried them. Because that Psittacosaurus Because there was no sign of it being bitten elsewhere, the researchers concluded that the mammal was indeed preying on a live dinosaur rather than eating a carcass.

It’s now 65 million years since the biological handover when this happened The age of dinosaurs is coming to an end and mammals are taking the lead on planet earth. You may have heard about the cause of the shift. A A large asteroid entered the Earth’s atmosphere, possibly in springand crashed into Mexico’s Yucatán Peninsula, ending the age of dinosaurs.

You may know the name of the beaked dinosaur featured in the newly announced specimen. PsittacosaurusThe latest claim to fame is the 2021 reveal of the Dinosaur Cloaca, the general purpose hole dinosaurs used for waste disposal and laying eggs.

Despite being soft tissue, the cloaca of this specimen was remarkably preserved thanks to the preservation conditions in Liaoning, China, the region where it was found. The newly announced fossil was also found in Liaoning, west of Lujiatun Village, in 2012.

The cloaca and the new fossil are both part of the Jehol biota, a fossilrich part of Northeast China with unique conservation conditions. In the paper, the researchers point out that fake fossils from the region have been reported before. However, given the entanglement of the two creatures in the new fossil, they assumed the fossil was real.

The remarkable fossil shows a mammal chasing a dinosaur.

The remarkable fossil shows a mammal chasing a dinosaur.
photo: Gang Han

Of course they examined the place where the repenomamus Bite the psittacosaursand came to the conclusion that Because of the way the mammal’s teeth sunk into the dinosaur’s ribs, the fossil was real.

Mallon told Gizmodo that it’s possible repenomamus Hunted in packs there is no evidence to support this idea and the individual repenomamus That ended gum-deep in one Psittacosaurus Midriff was able to take on such dinosaurs alone.

The fossil is amazing not only for its state of preservation, but also for its subject: interactions between ancient mammals and dinosaurs. Fossil evidence of such interactions is not common, but two such events have now occurred in 2023; Earlier this year another team of Researchers found a Microraptor Zhaoinus with the foot of a small mammal in its mouth. This fossil was found—you might have guessed it—in the Jehol biota of northeastern China.

“As prolific as the fossil beds in the Lujiatun area are, there are still many unanswered questions about this ancient ecosystem,” Mallon said. “There is a tendency in these fossil sites to preserve only the small animals that were there at the time. Presumably the larger dinosaurs escaped the volcanic mudslides that killed the smaller animals, so I’d like to learn more about the large animals that live in this area, which requires further exploration.”

prospect of paleontologists. The most intimate windows into deep time show how ancient creatures interacted, not just what they looked like. You can now remove “Mammals take on dinosaurs more than twice their size” from your 2023 bingo card.

More: Some paleontologists think they’ve found fossilized dinosaur DNA. Others are not so sure

Zack Zwiezen

Zack Zwiezen is a USTimesPost U.S. News Reporter based in London. His focus is on U.S. politics and the environment. He has covered climate change extensively, as well as healthcare and crime. Zack Zwiezen joined USTimesPost in 2023 from the Daily Express and previously worked for Chemist and Druggist and the Jewish Chronicle. He is a graduate of Cambridge University. Languages: English. You can get in touch with me by emailing

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