A decade of new fossil discoveries that have more than doubled the number of known tyrannosaur species has changed perceptions of the huge dinosaur with the tiny arms, a release from the American Museum of Natural History says.
Older and smaller tyrannosaurs have made the evolutionary tree of this group richer and more complex, and innovative research has added an enormous amount of information about tyrannosaurs, so much so that the group could now be considered an exemplar for paleontology research, scientists say.
"T. rex is the most iconic of all dinosaurs," Mark Norell, curator in the Division of Paleontology at the museum, says. "Its star power has allowed a research focus into questions not normally undertaken with fossils, questions like bone growth, biomechanics, and neurology."
"We know more about tyrannosaurs than any other group of dinosaurs -- even more than some groups of living organisms," Stephen Brusatte, a graduate student affiliated with the museum, said.
"Over the past year, five new species of tyrannosaurs have been described, and over the last ten years we have found the oldest and smallest members of the group," he said. "Now we can understand the family tree of tyrannosaurs in unprecedented detail.
"T. rex is really just the tip of the iceberg of tyrannosaur diversity, and honestly, is quite abnormal when compared with other members of the group. For most of their evolutionary history, tyrannosaurs were small and living in the shadow of other giant apex predators," Brusatte said.
"They stayed small until the end of the Cretaceous -- the final 20 million years of dinosaur history."