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Sometime in the Cretaceous period, 120 million years ago, a dinosaur wolfed down its last meal – a small mammal the size of a mouse. And it’s still there.
A researcher with a sharp eye spotted the mammal’s foot preserved inside the intestines of a fossilized Microraptor zhaoianus, a feathered therapsut less than a meter (3 feet) long.
“At first I couldn’t believe it. It was a small rodent-like mammal foot about a centimeter (0.4 inches) long perfectly preserved inside a Microraptor skeleton, says Hans Larsson, a professor of biology at McGill University’s Redpath Museum in Montreal. Larsson came across the fossil while visiting museum collections in China.
“These findings are the only solid evidence we have about the food consumption of these long-extinct animals – and they are exceptionally rare,” Larsson said in a press release.
The research, which was published in the Journal of Vertebrate Paleontology on December 20, said this was only the 21st known example of a fossilized dinosaur with its last meal preserved.
It is rarer still to find that a mammal was on the menu; there is only one other such example in the fossil record.
“We already know about Microraptor specimens preserved with parts of a fish, a bird and a lizard in their stomachs. This new find adds a small mammal to their diet, suggesting that these dinosaurs were opportunistic and not picky eaters,” said Larsson, a co-author of the study, in a statement.
“Knowing that Microraptor was a generalist predator provides a new perspective on how ancient ecosystems may have functioned and a possible insight into the success of these small, feathered dinosaurs,” he explained.
Generalist predators, such as foxes and crows, are important stabilizers in today’s ecosystems because they can feed on several species, says the press release. According to the research, Microraptor is the first known example of a generalist predator in a dinosaur age.
It was possible that other dinosaurs from the therapod family, which included Tyrannosaurus rex, may also have shared a similarly murky diet, the study said.
The Microraptor fossil was discovered in the rich fossil deposits of Liaoning in northeastern China in the early 2000s. The specimen, which has feathers on its wings and legs, was one of the first feathered dinosaurs to be discovered.
“Although this mammal certainly would not have been a human ancestor, we can look back at some of our ancient relatives being a meal for hungry dinosaurs,” said study co-author Dr. David Hone, a reader in zoology at Queen Mary University of London, said in a statement.
“This study paints a picture of a fascinating moment in time — one of the first records of a dinosaur eating a mammal — even if it’s not quite as terrifying as anything else in ‘Jurassic Park.'”