Early Bird Fossil: Is Aurornis Xui The World's First Bird Or A Dinosaur?
An early bird fossil discovered in China last year is now thought to belong to the first known bird. The small, feathered bird, called Aurornis xui, has displaced Archaeopteryx as the earliest known bird, according to a new paper published in Nature.
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Aurornis is 160 million years old and from the Jurassic period. That puts it about 10 million years before Archaeopteryx, a feathered dinosaur previously thought to be the oldest bird.
"Our analyses indicate it as the most primitive bird known," said Andrea Cau, a vertebrate paleontologist and co-author of the Nature paper. "It was a small feathered dinosaur that lived in what is now China about 160 million years ago. It looked like a ground bird, but with a long tail, clawed hands and toothed jaws."
But are Aurornis and Archaeopteryx birds or are they dinosaurs? It's a question of considerable scientific debate.
Archaeopteryx was discovered in Germany in 1861. It had wings and feathers, like a bird, but it also had dinosaur traits like a bony tail and three-fingered claws. Scientists considered it a bird, or a transitional species between dinosaur and bird.
Aurornis xui was named after the Latin word for "daybreak" and in honor of Chinese paleontologist Xu Xing, who claimed in 2011 Archaeopteryx was not only not a bird, but that it was not even an ancestor to modern birds.
The Nature paper claims that Archaeopteryxwas one of the earliest birds, but that Aurornis xui has now trumped it as the first bird.
Paul Barrett at the Natural History Museum in London, said that the discovery of Aurornis xui emphasizes "how grey the dividing line is between birds and dinosaurs. There's such a gradation in features between them that it's very difficult to tell them apart. It only takes relatively small changes in our knowledge of these to flip around some of the evolutionary relationships between them."
Barrett concluded, "It's fair to call it a very primitive bird. But what you call a bird comes down to what you call a bird."
Luis Chiappe, a paleontologist at the Natural History Museum of Los, says that Aurornis is "bird-like," and that he tends to think of it not as a bird but "one of those true very close ancestors of bird."
"It pushes [back] the origins of birds -- or origin of animals that are very closely related to the bird," said Chiappe. "And that's quite exciting."
"Around the origin of birds 160 million or so years ago," Chiappe added. "There were many fossils that were experimenting with birdness -- getting more and more bird-like. What exactly the line is that made it to birds is not entirely clear...and this is just one candidate."
To further complicate the matter, Chiappe says there may be a bit of funny business going on with the Chinese-discovered Aurornis fossil. He told the Los Angeles Times that the fossil was so well preserved that it may be too good to be true. Chiappe noted that 80 percent of fossils in Chinese museums are suspected of being "enhanced" in some way, and that he'd like to see the actual fossil himself.
Scientists at the Yizhou Fossil and Geology Park in China bought the fossil from a local dealer, who claimed it had been unearthed in the northeast province of Liaoning.
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