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Bird brains appeared before birds

Dino-bird insights New evidence has emerged that puts a dent into the reputation of the famous 'first bird' - Archaeopteryx, a feathered descendant of the dinosaurs, which lived around 150 million years ago.

Three-dimensional scans of skulls of early birds and dinosaurs suggests that at least a few species of dinos that were contemporaries of Archaeopteryx had brains with the likely neurological wiring for flight, according to a paper published in the journal Nature.

"Archaeopteryx has always been set up as a uniquely transitional species between feathered dinosaurs and modern birds, a halfway point," says Amy Balanoff of the American Museum of Natural History.

"But by studying the cranial volume of closely-related dinosaurs, we learned that Archaeopteryx might not have been so special."

Balanoff's team used computed tomographic (CT) scans to get a high-resolution image of brain size and regions in a dozen existing and extinct species.

Compared to reptiles, birds have large brains in relation to their body size -- a phenomenon called "hyperinflation" which provides them with the superior vision and coordination needed to flight.

But the comparison turned up some bad news for Archaeopteryx.

Several other non-avian dinos that were sampled, including the feathery oviraptosaur and bird-like troodontid, had in fact larger brains relative to body size than Archaeopteryx did.

"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," says Balanoff.

The finding adds to evidence that the gene pool that led to the first birds was far wider than thought.

Just a few years ago, biologists had a list of supposedly exclusive characteristics for birds, such as feathers and wishbones.

But these have been found to exist among non-avian dinosaurs, and now hyperinflated brains can be added to the list.