The stomach of the teenage tyrannosaur Gorgosaurus libratus is a reward that retains on giving. A group of paleontologists in Canada discovered the stays of two meals preserved inside of its stomach cavity, together with the partially digested drumsticks of two birdlike dinosaurs. The findings have been described in a examine printed December 8 within the journal Science Advances and is the primary identified time that well-preserved intestine continents have been found in a fossilized tyrannosaur.
[Related: The ghosts of the dinosaurs we may never discover.]
Gorgosaurus lived about 75 million years in the past, or a number of million years earlier than its extra well-known relative the Tyrannosaurus rex. In the examine, the Gorgosaurus was estimated to be between 5 and 7 years previous when it died, or a teenager in dinosaur years. It in all probability weighed about 738 kilos, or 13 % of the physique mass of a absolutely grown Gorgosaurus. Adults have been about 33 toes lengthy and weighed upwards of 2,200 kilos.
The fossil was first found in 2009 by workers from the Royal Tyrrell Museum of Palaeontology in Dinosaur Provincial Park in Alberta. Technicians observed unusual options poking out of the fossil’s rib cage whereas they have been making ready it. These turned out to be small toe bones. Gut contents like these are hardly ever preserved in dinosaur fossils, however this specimen had the dismembered stays of two herbivorous dinosaurs–Citipes elegans.
The tyrannosaur solely ate the hind limbs of every tiny Citipes and they seem like the final and second-to-last meal that the Gorgosaurus consumed earlier than it died.
“It must have killed… both of these Citipes at different times and then ripped off the hind legs and ate those and left the rest of the carcasses,” examine co-author and University of Calgary paleontologist Darla Zelenitsky informed CNN. “Obviously this teenager had an appetite for drumsticks.”
Tyrannosaurs digested the bones of their prey of their stomach, as an alternative of regurgitating them the best way present-day birds do. Since the weather of the 2 Citipes people are at completely different levels of digestion, the group concludes that these have been two completely different meals eaten hours or days aside.
This specimen additionally reveals direct proof that younger Gorgosaurus had completely different diets than adults. Fully grown Gorgosaurus are identified to have hunted megaherbivore dinosaurs together with ceratopsians (horned dinosaurs) and hadrosaurs (duck-billed dinosaurs), based mostly on the tooth marks left behind on bones. They used their large skulls and tooth to seize their giant prey, chomp by way of bone, after which scrape and tear the flesh.
[Related: Scaly lips may have hidden the T-rex’s fearsome teeth.]
Juveniles weren’t but constructed to hunt such giant prey. They had extra slim skulls, blade-like tooth, and lengthy and slender hind limbs. This made them higher fitted to capturing and dismembering small and younger prey just like the Citipes discovered on this specimen. The group additionally believes that this type of prey was a most popular snack for these teenage dinos.
“This is a great case of showing small tyrannosaurids fed on small dinosaurs, much smaller than themselves,” University of Maryland paleontologist Thomas Holtz informed The Washington Post., “Whereas the grown-up versions, we have the evidence of their bite marks on big adults that were about the same size as adults.”
The dietary shift in the direction of consuming larger prey seemingly started across the age of 11. This is when the tyrannosaurs’ skulls and tooth began to get extra sturdy. Differences in food plan present a aggressive benefit by lessening competitors for sources in fashionable ecosystems. This similar technique might have been utilized when tyrannosaurs like Gorgosaurus lived. It would have allowed juveniles and adults to coexist in the identical ecosystem with much less battle. Occupying completely different ecological niches throughout their lifespan was seemingly one of the keys to tyrannosaurs’ evolutionary success as some of Earth’s carnivores.