Posted on 06/15/2006 2:56:31 PM PDT by nickcarraway
Scientists have uncovered remarkably preserved fossils – including feathers and webbed feet – of the oldest known relatives of modern birds, which also shores up the theory that birds evolved from aquatic environments.
Little is known about birds from the age of dinosaurs, since fossils that date back to the early Cretaceous Period – some 105 to 115 million years ago – are have rarely been found, the discovery reported in Friday's issue of the journal Science is particularly exciting for those trying to fill gaps in the avian family tree.
“I was totally blown away. I was stunned,” said Matthew Lamanna, assistant curator of vertebrate paleontology Carnegie Museum of Natural History in Pittsburgh, recalling his first glimpse of the fossils.
Lured by photographs of a fossilized bird wing, plants and colourful insects in 2003, Dr. Lamanna would go on to become a co-author of the study with a group researchers from China and the United States.
“We were lucky far beyond our expectations,” said report co-author Hai-lu You of the Chinese Academy of Geological Sciences of the treasure trove of fossils. “A world lost for more than 100 million years was being revealed to us.”
The fossil hunters describe five, tern-sized specimens of Gansus yumenensis, an amphibious bird, found near the town of Changma in northwestern China.
The site is an ancient lake bed where a partial leg first turned up in 1981. Over time, researchers painstakingly cut through the hard soil – taking some slabs and some samples as fine as paper – looking for more fossils. They found a second Gansus specimen in 2002.
Eventually the site would turn up 50 bird specimens, most of them Gansus. The fine sediment helped preserve the uncrushed and three-dimensional fossils, including wing feathers, down and skin between toes.
With most parts of Gansus accounted for – minus the skull and neck – scientists reconstructed the bird and produced something that looks strikingly similar to the modern loon.
Despite features that suggest flight, the scientists noted that pelvic limb elements showed characteristics of amphibious birds. That contrasts, however, with the long-standing belief that the Gansus acted more like a sandpiper by wading into water and probing the sediment near shore for food.
“Its anatomy, however, demonstrates that it was more similar to, but not as adept as, foot-propelled diving birds such as grebes, loons, and diving ducks,” the study concluded.
The webbing on the feet also supports evidence of footprints found elsewhere in Asia among early Cretaceous birds.
These birds, 10 million years older than oldest avian fossils previously discovered, were a kind of missing link in the evolutionary tree of the modern bird. The roots of that tree are now clearly aquatic.
Gansus, which belongs to the Ornithuran lineage, including modern birds, was on scene during the age of dinosaurs when another type of ancient bird ruled the sky.
The Enantiornitheans – or "opposite birds” – were so called because their shoulder joint is the opposite of modern birds. They are common in fossil sites, including the area where the first feathered dinosaur specimen appeared in northeast China a decade ago.
The opposite birds disappeared at the end of the Cretaceous period, and nobody really knows why.
While most of the bird specimens found at the Changma site seem to be Gansus, there are also an abundance of plants, insects, turtles, salamander and fish, which provides more good news for scientists.
“We'll be able to build a picture of the ecosystem the Gansus lived in,” Dr. Lamanna said.
Very interesting article.
Oldest known Byrd found in W. Virginia.
"Ever notice that Jack Nicholson is starting to look like me?"
soon to be soup.
Don't eat 'em! You'll get bird flu!
Well DUH. The other birds stayed so they did the opposite.
Rodan! meets Godzirra.
Ancestor of the ptarmigan.
Gods, Graves and Glyphs ping.
Thanks Nick! Also Coyoteman for the other FR topiclink. There's some other stories about this on the world wide webbed.
[rimshot!]
My favorite (so far) was the Telegraph's, "Pteroducktyl - the missing link". :'D
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