Researchers at University of Southampton have come up with a detailed family tree that shows how massive, ground-dwelling dinosaurs shrunk over a period of 50 million years to evolve into agile flying birds.
"These bird ancestors also evolved new adaptations, such as feathers, wishbones and wings, four times faster than other dinosaurs," says co-author Darren Naish, Vertebrate Palaeontologist at the University of Southampton.
"Birds evolved through a unique phase of sustained miniaturisation in dinosaurs," says lead author Associate Professor Michael Lee, from the University of Adelaide's School of Earth and Environmental Sciences and the South Australian Museum.
The study concluded that the branch of dinosaurs leading to birds was more evolutionary innovative than other dinosaur lineages. "Birds out-shrank and out-evolved their dinosaurian ancestors, surviving where their larger, less evolvable relatives could not," says Associate Professor Lee.
The study is published in the Journal Science.