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NSF PR 99-3 - January 21, 1999
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Rare Fossil Shows Theropod Dinosaurs Are Fast, Dangerous
'Turbocharged' Reptiles
Oregon State University (OSU) scientists funded by
the National Science Foundation (NSF) have completed
a study of what they say is the world's most perfectly
preserved fossil of a theropod, or meat-eating dinosaur.
They believe it provides an unprecedented view of
the biology of these ancient reptiles.
The bottom line? You wouldn't want to meet a theropod
in a dark alley. The research, to be published in
this week's issue of the journal Science,
offers insights into dinosaur metabolism, the warm-blooded
versus cold-blooded debate, the question of whether
or not dinosaurs might have been the ancestors of
birds, and the biology that helped them dominate the
world—and eventually may have led to their extinction.
"This exquisitely preserved fossil shows that theropod
dinosaurs had the ventilatory machinery to support
periods of high activity, but that they lacked bird-style
lungs or other anatomical features suggestive of a
sustained high metabolic rate," according to Zoe Eppley,
program director in NSF's division of integrative
biology and neuroscience, which funded the research.
"This find adds further support to the view that these
dinosaurs were not warm-blooded."
This fossil is helping confirm that "the dinosaurs
were indeed, by definition, cold-blooded, and that
in all likelihood, birds are not the descendants of
any known group of dinosaurs," said Nicholas Geist,
a paleobiologist at OSU. "The extraordinary condition
of this fossil allows us to 'hang some meat on the
bones' of these animals and bring them back to life
a bit. It's almost like a dinosaur dissection."
What that analysis reveals, Geist said, is an animal
that had the best of both worlds. Like other cold-blooded
animals, theropod dinosaurs had low metabolic rates
while at rest, an excellent strategy for conserving
energy. But their enhanced lung ventilation capacity
gave them the potential for the aggressive, extended
activity typical of birds and mammals. "Theropod dinosaurs
were fast, dangerous animals," Geist said, "certainly
not slow or sluggish. They could conserve energy much
of the time and then go like hell whenever they wanted
to. That might go a long way towards explaining why
they were able to dominate mammals for 150 million
years."
Geist and OSU colleague Terry Jones made these observations
after study in Salerno, Italy, of a fossil first discovered
just a few years ago of a baby Scipionyx, a meat-eater
that lived about 110 million years ago and bore some
similarity to a velociraptor. "Besides an intact skeleton,
this fossil shows remnants of liver, large intestine,
windpipe and even muscles," Jones said. "The baby
dinosaur probably died in a shallow, still, saltwater
marsh that preserved its structure incredibly well.
It's like a Rosetta stone for paleontology, and shows
us more about dinosaur biology than we ever knew before."
This type of physiology would provide some metabolic
advantages unlike that of any animal still alive today,
Jones said. "But for various reasons it only works
well in a warm climate, which most of the world had
during the age of dinosaurs. When the climate turned
colder or more seasonal variation developed, what
had once been the advantage of the dinosaurs became
their problem."
Adds Geist, "A lot of people who only see cold-blooded
reptiles moving slowly in temperate zones have no
concept of what they can do in warmer climates and
how well they can function. Then if you add in the
lung capacity that we're finding for meat-eating dinosaurs,
what you have is a turbocharged reptile. If you could
go back in time and see one, that's probably the last
thing you'd ever see."
Editors: Two color photographs in digital
format of the Scipionyx fossil can be obtained by
contacting Ute Vergin at 541-737-0785, or downloading
directly from the Web at:
http://www.osu.orst.edu/dept/ncs/photos/index.html
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