The brains of today's birds facilitate a level of cognitive prowess and behavioral complexity rivaled only by mammals. But how the avian brain evolved over many millions of years from an ancestral dinosaurian form has long puzzled scientists. That has now changed thanks to a spectacular fossil discovery in Brazil.

Researchers unearthed the skull of a previously unknown starling-sized bird species named Navaornis hestiae that was so well preserved, they were able to digitally reconstruct its brain and inner ear anatomy based on the shape of the braincase. It inhabited an arid environment about 80 million years ago during the Cretaceous Period, the last chapter in the age of dinosaurs.

"This finding is one-of-a-kind," said University of Cambridge paleontologist Guillermo Navalón, co-lead author of the study published on Wednesday in the journal Nature.