Fossils show living birds descended from waterfowl

WASHINGTON, June 16: A set of 110-million-year-old fossils from China is the earliest example of a modern-looking bird and strongly suggests ancestors of all living birds were waterfowl, researchers said.

The pigeon-sized bird probably resembled a tern or a loon,the researchers said. Called Gansus yumenensis, it would have been an accomplished flyer and diver and could well be one of the ancestors of modern birds, the researchers report in today's issue of the journal Science.

''Every bird living today, from ostriches ... to bald eagles, probably evolved from a Gansus-like ancestor,'' Matthew Lamanna of Carnegie Natural History Museum in Pittsburgh told a news conference.

Peter Dodson, professor of anatomy the University of Pennsylvania, who oversaw the research, said, ''Gansus is very close to a modern bird and helps fill in the big gap between clearly non-modern birds and the explosion of early birds that marked the Cretaceous period, the final era of the Dinosaur Age.'' The five skeletons come from an exceptionally rich fossil bed in China's Gansu Province, in a poor farming area near Changma, 2,000 km west of Beijing.

In the Cretaceous period, 100 million years ago, it would have been a lake, surrounded by lush plant life, filled with crocodiles and fish, and with dinosaurs and early mammals prowling on land.

Now the lake bed survives as layers of rock.

''You can walk up to a rock and peel off sheet after sheet like paper until you get to a fossil,'' said Jerald Harris of Dixie State College of Utah.

Hai-lu You of the Chinese Academy of Geological Sciences was studying at the University of Pennsylvania when many earlier fossil birds were discovered in China's northeastern Liaoning Province. He remembered that the rock beds in Gansu were similar and took an expedition there.

They struck paleontological gold and quickly gathered five nearly complete fossils of the early bird.

A computer program reconstructed the bird evolutionary tree and suggests the birds that gave rise to modern birds were waterfowl.

Gansus looks more like a modern bird than some birds that lived later in the Cretaceous period.

Its wings, legs and webbed feet closely resemble those of living loons and diving ducks, with a few exceptions. The birds had not yet evolved the hollow, air-filled bones that make modern birds to light and nimble, and it still had tiny claws at the end of its wings that probably would have made it slightly clumsy in flight, Harris said.

Reuters