Fossil from Alberta badlands finds prey inside the stomach of young tyrannosaur | CityNews Calgary

A dinosaur fossil discovered within the Alberta badlands has revealed new particulars concerning the weight loss program of younger meat-eating tyrannosaurs.

The analysis, revealed Friday within the journal Science Advances, relies on a well-preserved Gorgosaurus libratus specimen found in 2009 by a technician from the Royal Tyrrell Museum in Drumheller, Alta.

“We describe the first tyrannosaur skeleton found with prey items preserved inside the stomach,” Darla Zelenitsky, an affiliate professor within the division of earth, power and surroundings on the University of Calgary, mentioned in an interview.

“It’s a juvenile, or teenage, gorgosaurus … that had eaten two young and small birdlike dinosaurs called Citipes.”

Gorgosaurus was a tyrannosaur that lived 75 to 77 million years in the past, earlier than the Tyrannosaurus rex, in what’s now southern Alberta. The specimen was present in Dinosaur Provincial Park, about 220 kilometres east of Calgary.

The four-metre lengthy tyrannosaur had an estimated weight of 335 kilograms and, based mostly on the analysis, would have been about 5 to seven years previous when it died.

Zelenitsky mentioned the fossil represents the primary stable proof of the weight loss program of juvenile tyrannosaurs.

“It’s really an exciting find, because it’s unique and very unusual to find something like this, especially so well preserved.”

Co-author François Therrien, curator of dinosaur palaeoecology on the Royal Tyrrell Museum, mentioned it’s an vital discovery for a number of causes.

“Skeletons of young tyrannosaurs are extremely rare,” he mentioned. “Their bones are smaller and more fragile, so either they didn’t get fossilized back in (the) Cretaceous or they just get destroyed before we actually find them in the badlands.”

He mentioned a technician observed some toe bones whereas the specimen was being cleaned.

“The toe bones were definitely too small to belong to the tyrannosaur and they were coming through the rib cage from inside the animal,” Therrien mentioned.

They determined to organize the specimen from the within out and found that the bones of the 2 small dinosaurs have been preserved within the abdomen space.

“That was truly amazing, because the last meal — or in-place stomach contents — of a tyrannosaur had never been discovered before, so that was really exciting,” Therrien mentioned.

The analysis, he added, took a few years as a result of there have been so many items to place collectively. That included figuring out the bones within the abdomen, figuring out the age of these bones and the tyrannosaur, and determining how lengthy the bones had been within the abdomen.

Therrien mentioned it exhibits a change in weight loss program for tyrannosaurs as they matured.

“For a long time, we’ve known that adult and juvenile, or young, tyrannosaurs were very, very different physically.”

Adult tyrannosaurs, he mentioned, have been giant animals with large skulls and sturdy enamel that ate up plant-eating duckbill and horned dinosaurs, whereas juveniles have been frivolously constructed and athletic with blade-like enamel and lengthy legs.

“We 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.”

Therrien mentioned a transition from juvenile to grownup, just like folks going by way of puberty, possible came about for the tyrannosaur across the age of 11.

Researchers decided that the younger dinosaur was fairly surgical in the way it ate its prey.

“It went around and dissected away the back legs, swallowed those whole and basically didn’t eat anything else of the carcass,” mentioned Therrien. “It took the hind legs and nothing else, probably because that was the meatiest part of the animals.”

Zelenitsky added the younger gorgosaurus seemed to be fairly a fussy eater.

“Imagine that as a teenager,” she mentioned with amusing. “This gorgosaurus had an appetite for Citipes drumsticks, I guess.”

The analysis confirmed it had eaten the 2 birdlike dinosaurs in separate feeding occasions.

This report by The Canadian Press was first revealed Dec. 8, 2023.

Colette Derworiz, The Canadian Press