The first evidence that relatives of Tyrannosaurus rex lived in the Southern Hemisphere is a foot-long piece of bone discovered in Australia.
A foot-long (30 centimeter) piece of bone unearthed in Australia is the first evidence that ancestors of the mighty T. rex once lived in the Southern Hemisphere.
The remains are from an animal much smaller than the famed predator, but add to the knowledge of how this type of dinosaur evolved.
"The new discovery tells us that 110 million years ago, in the middle of their history, tyrannosaurs were everywhere. So the question is, why did they achieve giant size as apex predators in the north, but dwindle away in the south?" Benson said in an interview via e-mail.
Dinosaurs dominated the land for 170 million years, holding the place in the ecology that mammals do today, Benson explained. Learning about how species change and diversify, and about mass extinctions in the past, can help us understand modern threats, he said.
In addition, he said, learning about ancient creatures helps in understanding the evolution of modern animals.
"For instance, in recent history paleontologists established that dinosaurs gave rise to birds. Prior to this, birds were a mystery," Benson explained. "They have lots of distinctive features, feathers, warm-blood, air-filled bones, but there was no consensus on where they came from. Now we know, we can find out how they evolved.
"Tyrannosaurs are relatively close to birds so knowing about then gives us one piece of the puzzle," he said.