Megan Gannon, News Editor
Date: 28 March 2013 Time: 11:41 AM ET
The discovery of microscopic color-making structures in
fossilized feathers has recently made it possible for scientists to picture
dinosaurs and ancient birds in their natural hues.
But a group of researchers warns we might not be able to
paint a Microraptor shimmery
black or give the giant
penguin a maroon and gray coat just yet.
To reconstruct the elusive color of feathered dinosaurs,
scientists have zeroed in on melanosomes, melanin-loaded organelles typically
present in the cells of the skin, hair and feathers whose colors (which range
from black to brown to reddish) are each associated with a specific geometry.
Though the visible color of melanosomes often degrades over time, their
preserved size, shape and arrangement and can give some hints about their
original color.
But the melanosomes encased in feather fossils today could
have a distorted shape that leads scientists to the wrong conclusion about
their true color, according to the new study.
Since scientists don't have hundreds of millions of years
to watch how feather fossilization takes place from start to finish, Maria
McNamara, of the University of Bristol, and her colleagues simulated a long
burial by popping bird feathers into an autoclave, subjecting them to
temperatures up to 482 degrees Fahrenheit (250 degrees Celsius) and intense
pressure, about 250 times that of the atmosphere. The researchers found that
the melanosomes shrank under these harsh conditions.
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