Navaornis skull (VIDEO) University of Cambridge This video is under embargo. Please login to access this video. Caption A ‘one of a kind’ fossil discovery could transform our understanding of how the unique brains and intelligence of modern birds evolved, one of the most enduring mysteries of vertebrate evolution. Researchers have identified a remarkably well-preserved fossil bird, roughly the size of a starling, from the Mesozoic Era. The complete skull has been preserved almost intact: a rarity for any fossil bird, but particularly for one so ancient, making this one of the most significant finds of its kind. Credit Guillermo Navalón Usage Restrictions Please credit Guillermo Navalón License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.