Many dinosaurs developed the brain structure necessary for flight long before they evolved the ability to fly according to a new study from Dr. Amy Balanoff, a postdoctoral researcher at Stony Brook University. As Denise Chow at Fox News Science reports, it turns out that the transition from dinosaur to bird was far broader than initially thought.
“What we think of as birdlike features they keep falling down the evolutionary tree," Balanoff told Chow. "What's really interesting about birds is that as their brain develops, it fills so much of the cranial cavity that it creates an impression on the surrounding bones… if you fill that space in and get rid of the bones, you have a cast of what the brain looked like during life."
CT scans used to measure disnosaurs' brain
Balanoff and her fellow researchers didn’t literally fill cranial cavities with casting materials, but instead used a series of CT scans to measure the cavities of dozens of specimens, and what they found was that features normally associated with flight, especially a large frontal lobe, were already present in many dinosaur brains. They also found some evidence of a feature called the wulst, which is present in some, though not all, of the transitional species that they looked at. The wulst is vital for the rapid information processing and motor control necessary while in flight.
“The story of brain size is more than its relationship to body size," said co-author Dr. Gabriel Bever, an assistant professor at New York Institute of Technology. "If we also consider how the different regions of the brain changed relative to each other, we can gain insight into what factors drove brain evolution.”
Archaeopteryx: an example of transitional animal
Before these findings, paleontologists normally held up a species called Archaeopteryx as an example of a transitional animal, something in between dinosaurs and birds, but now it turns out that Archaeopteryx isn’t quite as unique as previously thought. It appears that there were multiple dinosaur species evolving along similar lines, and that their brains were all changing in a way that would make it possible for them to evolve the ability to fly.
“Our study shows Archaeopteryx isn't unique in being in that space between more primitive dinosaurs and birds," said Balanoff. "We found all these other closely related species that also fall in that close transitional space."