Washington: Some non-avian dinosaurs evolved the brainpower necessary to fly before they actually took to the air as birds, a new study has revealed.
Based on high-resolution X-ray computed tomographic (CT) scans, the study, takes a comprehensive look at the so-called `bird brain.`
In the new study, scientists have revealed that at least a few non-avian dinosaurs had brains that were as large or larger than that of Archaeopteryx, indicating that some dinosaurs already suspected of possessing flight capability would have had the neurological hardwiring necessary for this behaviour.
Lead author Amy Balanoff, a research associate at the American Museum of Natural History and a postdoctoral researcher at Stony Brook University, said that Archaeopteryx has always been set up as a uniquely transitional species between feathered dinosaurs and modern birds, a halfway point.
She said that by studying the cranial volume of closely related dinosaurs, we learned that Archaeopteryx might not have been so special.
The researchers used CT scanners at the University of Texas, Ohio University, Stony Brook University, and the Museum to peer inside the braincases of more than two dozen specimens, including modern birds, Archaeopteryx, and closely related non-avian dinosaurs like tyrannosaurs. By stitching together the CT scans, the scientists created 3-D reconstructions of the skulls` interiors.
In addition to calculating the total volume of each digital brain cast, the research team also determined the size of each brain`s major anatomical regions, including the olfactory bulbs, cerebrum, optic lobes, cerebellum, and brain stem.
The researchers found that in terms of volumetric measurements, Archaeopteryx is not in a unique transitional position between non-avian dinosaurs and modern birds.
Several other non-avian dinosaurs sampled, including bird-like oviraptorosaurs and troodontids, actually had larger brains relative to body size than Archaeopteryx.
Balanoff added that if Archaeopteryx had a flight-ready brain, which is almost certainly the case given its morphology, then so did at least some other non-avian dinosaurs.
The researchers also examined another factor that is important to flight in modern birds: a neurological structure called the wulst, which is used in information processing and motor control.
The team identified an indentation in the digital brain cast of Archaeopteryx that might be homologous to the wulst seen in living birds. But this indentation is not found in non-avian dinosaurs that have bigger brains than Archaeopteryx, presenting the research team with a new question to explore in the future.
The study has been published in Nature.