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NYTimes.com Article: Fossil of 4-Winged Dinosaur Casts Light on Birds and Flight



This article from NYTimes.com 
has been sent to you by dinogeorge@aol.com.


This appeared in the NYTimes today. Thought I'd send it to the list to test 
whether such articles will arrive there in readable form.

dinogeorge@aol.com


Fossil of 4-Winged Dinosaur Casts Light on Birds and Flight

January 23, 2003
By JOHN NOBLE WILFORD 




 

Scientists in China have found the fossils of a feathered
creature, identified as a small dinosaur, that they say
casts new light on the origin of birds and their ability to
fly. 

With two sets of wings, one on the forelimbs and the other
on its legs, it was a strange-looking animal, something
like a scaled-up, three-foot-long dragonfly, but with
feathers. All four wings were covered with feathers
arranged in a pattern similar to that on modern birds. Even
its long tail was fringed with feathers. 

Reporting the discovery in today's issue of the journal
Nature, the Chinese paleontologists said the animal
probably used its four wings to glide from tree to tree,
much as flying squirrels do today. This represented, they
said, a previously unknown intermediate stage in the
evolution of birds and flight. 

"The significance of the new fossils is far beyond the
strange appearance," the leader of the discovery team, Dr.
Xing Xu of the Institute of Vertebrate Paleontology and
Paleoanthropology in Beijing, said in a statement. "It
brings important information to the long-debated issue of
avian flight origin." 

Some scientists said the new evidence could yield the
answer to the question of how birds first took to flight:
from the ground up, or from the trees down? Did some fleet
reptiles flap their feathered forelimbs to run faster and
faster, until they became airborne? Or did some
tree-dwelling reptiles glide through the forest canopy,
eventually turning the experience into powered flight? 

Only a week ago, other scientists had advanced indirect
evidence that seemed to support the ground-up hypothesis.
Observations of chukar partridges, a modern flightless
bird, suggested that flight may have evolved in two-legged
dinosaurs that flapped their feathered forelimbs to get
better traction in climbing slopes. 

But Dr. Richard O. Prum, an ornithologist at the University
of Kansas, said the four-winged dinosaur, which lived about
125 million years ago, "provides striking support for the
arboreal-gliding hypothesis of the origin of bird flight." 

"Clearly these were bizarre creatures and an important
discovery," said Dr. Mark A. Norell, a paleontologist at
the American Museum of Natural History in New York. But he
said it was premature to speculate on the implications of
the wings for early bird flight. 

The discovery team wrote that the "forelimb and the leg
feathers would make a perfect aerofoil together." The team
said the findings were important for understanding how
ancestors of birds, widely thought to be dinosaurs, "first
learned to glide by taking advantage of gravity before
flapping flight was acquired in birds." 

Even though he disputes the predominant view of a direct
link between dinosaurs and birds, Dr. Alan Feduccia, an
ornithologist at the University of North Carolina at Chapel
Hill, called the newfound fossil "a new kind of animal that
we've never seen before." Its characteristics, he said,
"argue against a ground-up origin of flight." 

Dr. Xu's team noted that the presence of feathers on the
legs would be a hindrance to running fast. It thus
"provides negative evidence for the ground-up hypothesis." 

In an accompanying article in Nature, Dr. Prum cautioned
that "substantial questions remain" concerning how the
fossil animal used its four wings and whether its shoulders
and wings would have sustained powered flight. 

Dr. Xu said the new fossil represented a distinct species
of the small predatory dinosaurs known as dromaeosaurs. It
has been given the name Microraptor gui, honoring the
Chinese paleontologist Gu Zhiwei. 

The outlines of four feathered wings, the Chinese
scientists said, showed clearly in all six specimens found.
The specimens were uncovered recently in Liaoning, a
fossil-rich province of northeastern China. Each creature
was about three feet long from head to the tip of its long
tail, but its body was only about the size of a pigeon's. 

The Chinese scientists said it was hard to imagine from
some of the fossil remains that these little animals were
ground dwellers and could run fast on two legs, as
postulated in the ground-up theory. 

The Liaoning fossil beds have yielded much of the evidence
for feathered dinosaurs and a dinosaur-bird link. Last
year, other Chinese scientists reported finding a larger,
unnamed dromaeosaur with modern-type feathers on its
forelimbs. 

Stephen Czerkas, director of the Dinosaur Museum in
Blanding, Utah, said recently that this evidence suggested
that winged dromaeosaurs might have been able to fly. In
that case, he argued, the dromaeosaurs were not dinosaurs
but birds. 

As long ago as 1915, an American naturalist, William Beebe,
conceived of the idea that perhaps the earliest birds had
four wings. The notion came to him from studying what
appeared to be vestiges of such a configuration on young
chicks. He was wrong about this particular evidence, but
may have been prescient after all. Microraptor gui, Dr.
Prum said, "looks as if it could have glided straight out
of Beebe's notebooks."

http://www.nytimes.com/2003/01/23/science/23DINO.html?ex=1044441740&ei=1&en=8ee6dd3aedee8b70



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