The New York Times, January 26, 1999, Tuesday, Science Desk
HEADLINE: Turning Dinosaur Theory on Its Paleobiological Tail
BYLINE: By MALCOLM W. BROWNE
By shining ultraviolet light on the fossil of a baby dinosaur that
had collected dust in a file drawer in Italy for 15 years,
paleontologists have discovered astonishingly well-preserved anatomical
details that have rekindled one of the most intense debates in
The discovery has cast doubt on two widely held theories: that
dinosaurs were warmblooded and that they were the ancestors of birds.
Many paleontologists in recent years have come to accept the theory
that at least some dinosaurs could maintain steady body temperatures by
themselves. Many paleontologists are also convinced that birds are
closely related to dinosaurs, probably as their direct descendants. Part
of the evidence for this is the striking similarity of the skeletons of
some dinosaurs to those of birds. The baby dinosaur recently
examined was first found embedded in a limestone formation north of
Naples in 1983. Last year, after its rediscovery in the Archeological
Administration in Salerno, paleontologists who examined it were
astonished to find that much of its flesh, including many of its
internal organs, had been preserved in fossil form -- an extraordinary
discovery. The unique fossilized dinosaur, named Scipionyx samniticus,
has by far the best preserved fossil organs of any dinosaur ever found,
Since the initial investigation, which was reported a year ago, a
team of paleontologists headed by Dr. John A. Ruben of Oregon State
University at Corvallis and Dr. Willem J. Hillenius of the College of
Charleston, S.C, has examined the fossil under ultraviolet radiation.
Friday the journal Science published the result: a spectacular picture
in fluorescing colors, in which the little animal's organs stand out as
vividly as color-coded engineering diagrams.
"It's amazing," said Dr. Larry Martin, a paleontologist at the
University of Kansas. "It's essentially a dinosaur that's been
Paleontologists who have seen the ultraviolet pictures of Scipionyx
agree that they are uniquely revealing. But experts are far from
agreeing on the interpretation of the images.
Dr. Ruben and his colleagues argue that the fossil provides strong
evidence that dinosaurs had a breathing mechanism similar to that of
modern crocodiles and completely different from that of birds. From this
and some other evidence, they deduced that theropod ("beast footed")
dinosaurs, including the mighty Tyrannosaurus rex, were coldblooded, but
were capable of spurts of intense activity.
A member of Dr. Ruben's group, Nicholas R. Geist, said, "What you
have is a turbocharged reptile."
Scipionyx, which in life probably somewhat resembled the fierce
velociraptors depicted in the movie "Jurassic Park," lived about
million years ago. This specimen, an infant that apparently died shortly
after it was hatched, failed to attract much scientific interest at the
time it was found.
But it was later discovered that its different body parts were
selectively mineralized by different chemicals in the marine sediments
in which it was buried. This causes the fossilized organs to fluoresce
in different colors when exposed to ultraviolet.
The animal's colon glows bright yellow and appears to lie very close
to its spinal column. In modern reptiles, the colon is arranged like
this only in crocodiles, Dr. Ruben said.
In another possible similarity with crocodiles, scientists found
evidence in the infant dinosaur of a specialized breathing device called
a hepatic piston. In the crocodile, Dr. Ruben said, the piston is a
large liver driven by muscles that pull it in and out to move air
through the lungs. The colon lies near the crocodile's spine to leave
room for the liver to move freely.
Scipionyx's lungs themselves were not preserved, but Dr. Ruben
identified a large organ that glows blue under ultraviolet light as its
liver. The relative positions and sizes of these and other organs mark
them as crocodilian in type, he said.
By contrast, Dr. Ruben said, a bird's colon extends right through the
middle of its abdominal cavity.
"It seems clear," he said in an interview, "that a bird's
different system of breathing, in which air is continuously drawn
through its lungs, could not have evolved from the hepatic-piston system
we see in this theropod dinosaur."
The indications, however faint, that Scipionyx had diaphragmatic
muscles to assist its liver piston in breathing suggest that the animal
may have been an ectotherm (coldblooded), but was capable of sustaining
oxygen consumption rates and activity levels beyond those of modern
reptiles, Dr. Ruben said.
These views were strongly endorsed by Dr. Alan Feduccia, an
ornithologist at the University of North Carolina, who has long argued
that birds could not have descended from dinosaurs.
"I think John Ruben has done a remarkable job -- a nice piece of
detective work on a beautiful specimen," Dr. Feduccia said.
But Dr. Lawrence Witmer, an evolutionary biologist at Ohio
University's College of Osteopathic Medicine in Athens, was one of the
experts who challenged Dr. Ruben's conclusions.
"We have a ton of evidence for the view that birds descended from
theropod dinosaurs, and John Ruben's conclusions fly in the face of this
abundant evidence," Dr. Witmer said.
"He raises some intriguing points," he added, "but I'm
that we're really seeing a hepatic piston in this fossil. Remember,
we're seeing it in crushed form. Also, how do we know that bird
breathing systems could not have evolved from crocodile-like systems?
The history of life has often confounded theory."
He said that Dr. Ruben's ideas might turn out to be correct, but that
further evidence was needed to settle some large doubts.
Dr. Martin, of the University of Kansas, suggested, however, that the
evidence already appeared to be in hand.
Regarding the conclusions of the Oregon State University team, he
said: "There's actually no way they could be wrong about this. The
Scipionyx specimen has the best preservation ever seen. It's one of the
biggest discoveries of this decade. It tells us more about dinosaurs
than any other specimen.
"The positions of the dinosaur's windpipe and colon serve as
independent checks that the animal did not have a bird's breathing
apparatus," he said. And, he said, the external shape of theropod
dinosaurs, "with deep, narrow body walls, is exactly the design you
would expect for an animal with a hepatic piston."
As for the scientists who hold to the bird-dinosaur connection, he
said: "They're really cast in stone. Despite this new evidence, it's
going to be very hard for them to change their minds now."