Some nonavian dinosaurs, including carnivorous tyrannosaurs, may have had brains that were hardwired for flight long before even the earliest known birds started flapping their wings, a new study finds.
Scientists used high-resolution CT scanners to closely study the craniums of modern birds, nonavian dinosaurs and Archaeopteryx, considered by some to be one of the earliest known birds. They found that characteristics of the typical "bird brain" could be found much earlier in history than was previously thought.
"What we think of as birdlike features they keep falling down the evolutionary tree," said study lead author Amy Balanoff, a research associate at the American Museum of Natural History and a postdoctoral researcher at Stony Brook University, both in New York. [Images: Dinosaurs That Learned to Fly]
Archaeopteryxlived roughly 151 million to 149 million years ago, during the late stage of the Jurassic era. This early bird specimen has been branded as an evolutionary bridge between dinosaurs and modern birds, due to its signature blend of avian and reptilian features. The new findings, however, question whether Archaeopteryx, which was about the size of a raven, really was an evolutionary intermediate.
"Archaeopteryx has always been held up as a transitional species between nonavian dinosaurs and birds, but our study shows Archaeopteryx isn't unique in being in that space between more primitive dinosaurs and birds," Balanoff told LiveScience. "We found all these other closely related species that also fall in that close transitional space."
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