The oldest known bird, Archaeopteryx lithographica, lived roughly 150 million years ago and had modern feathers. But no one knows what earlier feathers may have looked like.
"To have an incredibly new and complex thing suddenly arise with no known antecedents is tough to explain," says Richard O. Prum, an ornithologist at the University of Kansas in Lawrence. Prum and his coworkers from the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing now report they've found feather antecedents on the remains of Sinornithosaurus millenii, a 124-million-year-old raptor dinosaur from Liaoning, China.
Although the Sinornithosaurus fossil is younger than that of Archaeopteryx, the newly described s