A dinosaur fossil found in the Alberta badlands has revealed new details about the diet of young meat-eating tyrannosaurs.
The research, published Friday in the journal Science Advances, is based on a well-preserved Gorgosaurus libratus specimen discovered in 2009 by a technician from the Royal Tyrrell Museum in Drumheller, Alta.
B次元官网网址淲e describe the first tyrannosaur skeleton found with prey items preserved inside the stomach,B次元官网网址 Darla Zelenitsky, an associate professor in the department of earth, energy and environment at the University of Calgary, said in an interview.
B次元官网网址淚tB次元官网网址檚 a juvenile, or teenage, gorgosaurus B次元官网网址 that had eaten two young and small birdlike dinosaurs called Citipes.B次元官网网址
Gorgosaurus was a tyrannosaur that lived 75 to 77 million years ago, before the Tyrannosaurus rex, in what is now southern Alberta. The specimen was found in Dinosaur Provincial Park, about 220 kilometres east of Calgary.
The four-metre long tyrannosaur had an estimated weight of 335 kilograms and, based on the research, would have been about five to seven years old when it died.
Zelenitsky said the fossil represents the first solid evidence of the diet of juvenile tyrannosaurs.
B次元官网网址淚tB次元官网网址檚 really an exciting find, because itB次元官网网址檚 unique and very unusual to find something like this, especially so well preserved.B次元官网网址
Co-author Fran莽ois Therrien, curator of dinosaur palaeoecology at the Royal Tyrrell Museum, said itB次元官网网址檚 an important discovery for several reasons.
B次元官网网址淪keletons of young tyrannosaurs are extremely rare,B次元官网网址 he said. B次元官网网址淭heir bones are smaller and more fragile, so either they didnB次元官网网址檛 get fossilized back in (the) Cretaceous or they just get destroyed before we actually find them in the badlands.B次元官网网址
He said a technician noticed some toe bones while the specimen was being cleaned.
B次元官网网址淭he toe bones were definitely too small to belong to the tyrannosaur and they were coming through the rib cage from inside the animal,B次元官网网址 Therrien said.
They decided to prepare the specimen from the inside out and discovered that the bones of the two small dinosaurs were preserved in the stomach area.
B次元官网网址淭hat was truly amazing, because the last meal B次元官网网址 or in-place stomach contents B次元官网网址 of a tyrannosaur had never been discovered before, so that was really exciting,B次元官网网址 Therrien said.
The research, he added, took many years because there were so many pieces to put together. That included identifying the bones in the stomach, determining the age of those bones and the tyrannosaur, and figuring out how long the bones had been in the stomach.
Therrien said it shows a change in diet for tyrannosaurs as they matured.
B次元官网网址淔or a long time, weB次元官网网址檝e known that adult and juvenile, or young, tyrannosaurs were very, very different physically.B次元官网网址
Adult tyrannosaurs, he said, were large animals with massive skulls and robust teeth that fed on plant-eating duckbill and horned dinosaurs, while juveniles were lightly built and athletic with blade-like teeth and long legs.
B次元官网网址淲e suspected that they were hunting something else, but we did not know what. Now this specimen finally shows young tyrannosaurs hunted small and young dinosaurs.B次元官网网址
Therrien said a transition from juvenile to adult, similar to people going through puberty, likely took place for the tyrannosaur around the age of 11.
Researchers determined that the young dinosaur was quite surgical in how it ate its prey.
B次元官网网址淚t went around and dissected away the back legs, swallowed those whole and basically didnB次元官网网址檛 eat anything else of the carcass,B次元官网网址 said Therrien. B次元官网网址淚t took the hind legs and nothing else, probably because that was the meatiest part of the animals.B次元官网网址
Zelenitsky added the young gorgosaurus appeared to be quite a fussy eater.
B次元官网网址淚magine that as a teenager,B次元官网网址 she said with a laugh. B次元官网网址淭his gorgosaurus had an appetite for Citipes drumsticks, I guess.B次元官网网址
The research showed it had eaten the two birdlike dinosaurs in separate feeding events.
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