Gorgosaurus theropod dinosaur eating Citypes. (From the bottom left) Comparison of the sizes of Gorgosaurus (right) and Citypes (two on the left) discovered as fossils. The bone depicted is the part discovered as a fossil this time, the fossil of Gorgosaurus used in this study. Fossils of the hind limbs of two Citypes were discovered in the area highlighted by the red circle. Julius Csotony/University of Calgary, provided by Darla Zelenitsky
What did dinosaurs eat? You can determine whether a dinosaur was herbivorous or carnivore by looking at the shape of the teeth left in fossils, or infer from the tooth marks left on the bones of herbivorous dinosaurs. However, it is not easy to find out exactly what food they ate unless direct fossil evidence is found.
In December last year, a joint research team led by François Therrien, curator of dinosaur paleoecology at Canada’s Royaltyrel Museum, and Darla Zelenitsky, a professor in the Department of Earth, Energy and Environment at the University of Calgary, analyzed fossil specimens of the carnivorous dinosaur Gorgosaurus that had meal contents left in the stomach. It was published in the academic journal ‘Science Advances’. (doi: 10.1126/sciadv.adi0505)
Gorgosaurus is a tyrannosaurus carnivorous dinosaur that lived in present-day North America during the late Cretaceous period of the Mesozoic Era, about 75 million years ago. Adults grow up to 8~9m. The specimen analyzed by the research team this time was a young dinosaur measuring 4 meters in length and weighing about 335 kg, which is only 13% of the adult weight.
While organizing fossil specimens, the research team discovered a fossil of the hind limbs of a baby dinosaur inside the ribcage of a young Gorgosaurus. The last meal in the stomach of Gorgosaurus became a fossil.
As a result of the analysis, it was revealed that the dinosaur inside the stomach was a theropod dinosaur called Citypes and contained the hind legs of two baby dinosaurs less than one year old. “It is possible that Gorgosaurus only ate the hind legs (the meaty part) of small prey,” Professor Zelenitsky said in a press release.
Until now, it has been known that adult Tyrannosaurus carnivorous dinosaurs generally eat large herbivorous dinosaurs. Through this discovery, it was revealed that Tyrannosaurus carnivorous dinosaurs were mid-predators that hunted small dinosaurs during their adolescence, but as they grew up, their type of prey changed to top predators that hunted large herbivorous dinosaurs.
Regarding this result, the research team analyzed that young and adult carnivorous dinosaurs did not compete with each other for food because they hunted prey that occupied different positions in the ecosystem, and that this “may have been the key to the evolutionary success of Tyrannosaurus.”
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February issue of Science Donga, [과학뉴스 ]The last meal of the carnivorous dinosaur Gorgosaurus was the hind leg of the dinosaur!
