SCIENCE PALEONTOLOGY : Fossil May Be Link Between Dinosaurs and Birds

A 135-million-year-old fossil found in 1987 in China has turned out to be the skeleton of the oldest bird ever found that lived in trees and flew like modern birds, scientists are announcing today.

Paleontologist Paul Sereno of the University of Chicago said the sparrow-sized animal had some dinosaur-like features and probably represents a transitional period during which birds were evolving into the creatures that we see today. The recent discovery is 10 million years younger than the oldest bird fossil, and that beast was quite different.

The older archaeopteryx lived on the ground, could probably climb trees, but could not fly. It bore little similarity to modern birds.

The newly discovered skeleton is fairly complete because it was preserved in the fine sediments of an ancient lake bed that hardened into rock. A lack of water current and oxygen reduced decay and kept the bones undisturbed, although the skull bones apparently floated apart before fossilizing, making the reconstruction slightly more difficult.

The discovery is being presented today at the annual meeting of the Society of Vertebrate Paleontology in Lawrence, Kan.

Sereno, who was asked by Chinese authorities to help study the fossil, said the reconstructed bird shows that the earliest birds were skilled fliers that were at home in trees, and not primarily land-dwelling animals as some scientists have maintained.

“If you saw this bird perched in a tree it would probably appear modern, with flying and perching abilities virtually identical to today’s birds,” Sereno said in a statement.

Yet the tiny bird, which has not yet been named, also had many primitive features, including three-clawed fingers along its wings that Sereno described as “very dinosaur-like.”

“It’s a surprise that this bird’s flight structures could be so well evolved while it still retains many of archaeopteryx’s dinosaur-like features,” Sereno said. “It’s exciting to find such a clear intermediary step between dinosaurs and the birds of today.”

Some experts take that a step further and maintain that today’s birds are so similar to dinosaurs that it is a mistake to say that the dinosaurs died out 65 million years ago. The birds of today, they argue, are simply descendants of earlier dinosaurs.

The unnamed bird, found near a farmer’s field in Liaoning Province in northeastern China, is 10 million years older than another tree-dwelling specimen found in Spain two years ago. Both birds suggest that creatures with modern flight capabilities originated much earlier than had been thought. Many experts had believed that early birds did not live in trees and used their wings only to flap themselves along the ground, possibly as recently as 75 million years ago.

Sereno and Cheng-gang Rao, curator of Beijing’s Natural History Museum, have been studying the fossil for several months at the University of Chicago. The fossil will be returned to the Beijing museum after the study is completed.

The research is supported partly by the National Geographic Society.