COLOR WERE THE DINOSAURS?
September 26, 2010
has seen Barney knows that some dinosaurs are purple. And movies such
as Jurassic Park and most children's' books about dinosaurs imply
that these prehistoric leviathans were brightly colored. But how can we
tell what color an animal was from a bone that has been buried for a hundred
were the dinosaurs? Some paleontologists have assumed that the body color
patterns of terrestrial animals now known only as fossils were comparable
to those of modern-day vertebrates, but documenting color in particular
species was considered impossible. During the past year, however, independent
studies by scientists from China, England, and the United States have
demonstrated that extinct relatives of the dinosaurs had body color and
have even suggested what some of the body color patterns were.
need to be considered when understanding how paleontologists know that
dinosaurs had body coloration. First, the earliest birds were a direct
evolutionary offshoot of the dinosaurs. Therefore, birds are more closely
related to dinosaurs, as well as to alligators and crocodiles, than to
today's modern reptiles such as snakes and lizards. Thus, some of the
findings about the skin characteristics of dinosaurs have been based on
examining feathers of ancient birds.
point is that some of the research has involved highly technical laboratory
equipment at microscopic levels that revealed the presence of structures
that are unimaginably small. The investigators examined the shape, size,
and microstructural characteristics of fossilized melanosomes. Melanosomes
are tiny bodies that are inside the cells of today's animals and that
can produce color. Jakob Vinther of Yale University and colleagues examined
fossilized feathers and found preserved melanosomes that had structural
arrangements similar to those that produce color in modern birds. The
discovery indicated that earlier birds and dinosaurs potentially used
Quanguo Li of the Beijing Museum of Natural History and colleagues provided
confirmation of variable plumage color in a feathered dinosaur from the
Late Jurassic in China. Although it had feathers covering its body, it
was not a flying animal. The specimen's face was dark gray with reddish
brown speckling, a reddish brown crown, and white limb feathers with black
markings on the tips. The investigators suggest that color may have been
important during early feather evolution as a signaling mechanism in a
manner similar to that of modern birds. Body colors can be important for
attracting mates, in threat displays, and for certain forms of camouflage.
Fucheng Zhang and Zhonghe Zhou of the Institute of Vertebrate Paleontology
and Paleoanthropology, Chinese Academy of Sciences, Beijing, Michael J.
Benton, University of Bristol, UK, and colleagues used scanning electron
microscopy to study fossilized material from the Early Cretaceous of China.
They examined skin structures, including the feathers of nonflying dinosaurs
with pennaceous feathers. These are the feather type most people are familiar
with, in which the feather has a main shaft with lateral vanes extending
out from it. They also examined dinosaurs without true pennaceous feathers.
The investigators determined that the melanosome structure was the same
as that found in modern birds.
that a type of pigment called phaeomelanin, which is reddish brown to
yellow, was present, as well as eumelanin, a pigment that is black gray.
The phaeomelanosomes were the first ever discovered in fossil material.
From a paleontological perspective, the research is significant in understanding
the origins and relationships between birds and dinosaurs. Identifying
the microscopic structures in the skin of nonflying dinosaurs as a likely
evolutionary forerunner of true feathers is also important.
But for those
of us who have been and continue to be fascinated with dinosaurs and who
like looking at artists' renditions of what they looked like, it is comforting
to know that some may have been colorful. To imagine a bright green Tyrannosaurus
rex with red eyes and a yellow stripe down its back attacking a blue brontosaurus
with red splotches is far more exciting than to imagine the same scenario
if those two animals are both a dull gray.
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