They are among the largest predators to ever walk on Earth, but experts discovered that some small tyrannosaurs were the size of a Border Collie when they took their first steps.
The first known fossils of tyrannosaur embryos shed light on the early development of megafauna, which could grow to 40 feet tall and weigh eight tons.
A team of paleontologists, led by a researcher from the University of Edinburgh, made the discovery by examining the fossilized remains of a small jawbone and claw that were discovered in Canada and the United States.
The production of a 3D scan of the fine fragments showed that they belong to small tyrannosaurs – their cousins T-Rex Which, depending on the size of the fossils, was about three feet long when hatched.
The team’s findings indicate that the tyrannosaur eggs – whose remains have not been found – were about 17 inches long, which the researchers say could aid in efforts to identify such eggs in the future and gain greater insights into the nesting habits of tyrannosaurs.
The analysis also revealed that the three-centimeter-long jawbone possessed distinctive Tyrannosaurus features, including a clear chin, indicating that these physical features were present before the animals hatched.
Little is known about the early evolutionary stages of dinosaurs – which lived more than 70 million years ago – despite being one of the most studied families of dinosaurs. Most of the tyrannosaur fossils previously studied were of young adult or older animals.
The study published in Canadian Journal of Geosciences, With support from the Royal Society and Natural Sciences, the Engineering Research Council of Canada, and the National Science Foundation. Researchers from the Universities of Alberta and Calgary in Canada, Montana and Chapman University in the United States also participated.
Dr Greg Vanston, from the University of Edinburgh’s School of Geosciences, who led the study, said: “These bones are the first window into the early life of dinosaurs and they teach us the size and appearance of young dinosaurs. We now know that they will be the largest offspring of eggs ever. Like their parents – they are both good signs for finding more material in the future. ”