March 9, 2012
Microraptor Had Black, Iridescent Feathers, Scientists Report
A four-winged, feathered dinosaur that was the size of a pigeon and lived approximately 130 million years ago had black feathers with an iridescent sheen, a team of US and Chinese researchers has revealed.
In their study, scientists from the Beijing Museum of Natural History, Peking University, the University of Texas at Austin, the University of Akron, and the American Museum of Natural History (AMNH) analyzed a specimen of the Microraptor, a non-avian dinosaur that in 2003 became the first four-winged dinosaur ever discovered.
According to a Thursday press release from the University of Texas, the researchers compared the patterns of pigment-containing organelles known as melanosomes from a Microraptor fossil with those found in the birds of today. The AMNH, in a separate statement, said that they compared the shape and density of the fossil against a melanosome database of modern birds at the Beijing Museum of Natural History.
Their research, the museum said, revealed that the Microraptor was "completely black with a glossy, weakly iridescent blue sheen" which university representatives compared to "the feathers of a crow." The discovery makes the Microraptor the earliest known species to have iridescent color in its feathers.
The researchers also discovered that Microraptor had a narrow tail with a pair of streamer feathers on it.
"A new reconstruction of the dinosaur will help scientists approach the controversy of how dinosaurs began the transition to flight," the University of Texas press release said. "Once thought to be a broad, teardrop-shaped surface or with a shape more like that of a paper airplane meant to help generate lift, Microraptor's tail fan is actually much narrower with two elongate feathers off of its tip. The researchers believe the tail feathering may have been ornamental and probably evolved for courtship and other social interactions and not as an adaptation for flight."
"This study gives us an unprecedented glimpse at what this animal looked like when it was alive," said Mark Norell, chairman of the AMNH's Division of Paleontology and one of the authors of a paper detailing the findings, which will be published in Friday's edition of the journal Science.
"There's been a lot of speculation about how the feathers of Microraptor were oriented and whether they formed airfoils for flight or whether they had to do with sexual display," he added. "So while we've nailed down what color this animal was, even more importantly, we've determined that Microraptor, like many modern birds, most likely used its ornate feathering to give visual social signals."
Melanosomes, the natural history museum notes, are usually round or cigar-like in shape and are so small that roughly 100 of them could fit across a single strand of human hair. They say that recently, paleontologists have begun using scanning electron microscopes to get a closer look at "well-preserved fossilized feather imprints," and they can tell whether or not the fossils were iridescent when they observe these pigment-containing organelles "organized in stacked layers" and, in this case, "uniquely narrow."
Image 1: Artist's rendering of Microraptor in its ancient habitat, iridescent plumage showing. Credit: Jason Brougham/UT-Austin
Image 2: Reconstruction of Microraptor based on new specimen and overlays of previous specimens. Credit: Mick Ellison/AMNH
Image 3: Detail of the tips of Microraptor's well-preserved leg feathers, from beneath its tail. Credit: Mick Ellison/AMNH
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