January 25, 2012
New Research Shows Feathered Dinosaur Could Fly
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An international team of researchers led by Brown University has shed some new light on whether the winged dinosaur Archaeopteryx could fly.
The team has determined that a well-preserved feather on the raven-sized dinosaur's wing was black, which is evidence that the feathers had traits that could help Archaeopteryx fly.
Also, the researchers determined that the fossilized feather's structure is identical to living birds, according to the research published in the journal Nature Communications.
"If Archaeopteryx was flapping or gliding, the presence of melanosomes [pigment-producing parts of a cell] would have given the feathers additional structural support," Ryan Carney, an evolutionary biologist at Brown and the paper's lead author, said in a press release. "This would have been advantageous during this early evolutionary stage of dinosaur flight."
The feather the researchers studied was discovered in a limestone deposit in Germany in 1861, which was just a few years after Charles Darwin's On the Origin of Species was published.
Researchers analyzed the feather and discovered that it is a covert, which means the feathers cover the primary and secondary wing feathers birds use in flight.
The group used a powerful electron microscope and located patches of hundreds of melanosomes still encased in the fossilized feather after two other unsuccessful attempts with different instruments.
"The third time was the charm, and we finally found the keys to unlocking the feather's original color, hidden in the rock for the past 150 million years," Carney said in a press release.
The team measured the length and width of the sausage-shaped melanosomes, which were about 1 micron long and 250 nanometers wide.
Researchers then compared Archaeopteryx's melanosomes with those found in 87 species of living birds.
"What we found was that the feather was predicted to be black with 95 percent certainty," Carney said.
The team said in order to better understand the melanosome's structure, they examined the fossilized barbules. These are tiny, rib-like appendages that overlap and interlock like zippers to give a feather its strength.
Carney said the barbules and the alignment of melanosomes are identical to those found in modern birds.
"We can't say it's proof that Archaeopteryx was a flier," Carney said in the press release. "But what we can say is that in modern bird feathers, these melanosomes provide additional strength and resistance to abrasion from flight, which is why wing feathers and their tips are the most likely areas to be pigmented."
"With Archaeopteryx, as with birds today, the melanosomes we found would have provided similar structural advantages, regardless of whether the pigmentation initially evolved for another purpose."
Image Caption: Paleontologists have long thought that Archaeopteryx fossils, including this one discovered in Germany, placed the dinosaur at the base of the bird evolutionary tree. Credit: Museum fÃ¼r Naturkunde Berlin
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