Fossilised fragments of a skeleton, hidden within a rock the size of a grapefruit, have helped upend one of the longest-standing assumptions about the origin of modern birds.
Researchers from the University of Cambridge and the Natuurhistorisch Museum Maastricht found that one of the key skull features that characterises 99% of modern birds — a mobile beak — evolved before the mass extinction event that killed all large dinosaurs, 66 million years ago. This finding also suggests that the skulls of ostriches, emus and their relatives evolved ‘backwards’, reverting to a more primitive condition after modern birds arose.
For more than a century, it had been assumed that the mechanism enabling a mobile beak evolved after the extinction of the dinosaurs. However, the new discovery ( Nature), suggests that our understanding of how the modern bird skull came to be needs to be re-evaluated, says a release.