[Paleopsych] NYT: The Making of a Vegetarian: A Dinosaur Is Caught in the Act
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Sat May 7 00:07:18 UTC 2005
The Making of a Vegetarian: A Dinosaur Is Caught in the Act
New York Times, 5.5.5
[I will be glad to send along any Creationist response that is specific to this
discovery, as opposed to general critiques of evolution, of which I have read
and sent many.]
By JOHN NOBLE WILFORD
Without government nutrition guidelines, a doctor's advice or some
primeval diet fad, entire species of dinosaurs sometimes forsook their
predatory, meat-eating lifestyle and evolved into grazing vegetarians.
Scientists now think they have found rare evidence of a species
undergoing just such a dietary transition 125 million years ago.
Paleontologists in Utah announced yesterday that they had discovered a
new species of dinosaurs in an intermediate stage between carnivore
and herbivore, on the way to becoming a committed vegetarian. They
could only speculate on the reasons for the change, but noted that it
occurred in a time of global warming and the arrival of flowering
plants in profusion, a tempting new food source.
Dr. James I. Kirkland, a paleontologist with the Utah Geological
Survey, said the new species, named Falcarius utahensis, was uncovered
two years ago at a remote dig site near the town of Green River. The
animal, about 13 feet long and 4½ feet tall, was a primitive member of
the therizinosaur group of feathered dinosaurs.
Under closer examination, Dr. Kirkland said, the Falcarius fossils
showed "the beginnings of features we associate with plant-eating
dinosaurs." The teeth were not the sharp, bladelike serrated teeth of
the typical predator, but smaller and adapted for shredding leaves. "I
doubt that this animal could have cut a steak," he said.
Other characteristics of an animal in transition to herbivory included
an expansion of the gut to digest the mass of fermenting plants,
stouter legs for supporting a bulkier body instead of the slender legs
of a fast-running predator, and a lengthening of the neck, perhaps to
reach for leaves higher in the trees.
Dr. Scott D. Sampson, chief curator of the Museum of Natural History
at the University of Utah, said the new fossils were "amazing
documentation of a major dietary shift" and promised to "tell us how
this shift happened."
The scientists described and interpreted the findings in interviews
and a teleconference from Salt Lake City. A detailed report is being
published today in the journal Nature.
Dr. Mark A. Norell, a dinosaur specialist at the American Museum of
Natural History who was not involved in the research, said the fossils
were well preserved and the teeth appeared to be similar to those of
plant-eating dinosaurs. But he questioned how much scientists would be
able to learn from the specimen about the change from meat eating to
Dr. Sampson said, "Falcarius represents evolution caught in the act, a
primitive form that shares much in common with its carnivorous kin,
while possessing a variety of features demonstrating that it had
embarked on the path toward more advanced plant-eating forms."
Dr. Norell agreed that the new species "is a very important and
interesting animal," primarily because it is a rare early example of
the therizinosaur group in North America. Falcarius is anatomically
more primitive than the better-known therizinosaurs that were
prevalent in China about 90 million years ago and had already evolved
as plant eaters.
Lindsay E. Zanno, a doctoral student in paleontology at Utah, said
Falcarius was "the most primitive known therizinosaur, demonstrating
unequivocally that this large-bodied group of bizarre herbivorous
dinosaurs" came from predatory carnivores like the swift, fierce
Velociraptor. Falcarius and Velociraptor had a common ancestor.
Scientists say all the vegetarian dinosaurs evolved from ancestors
that were carnivores. Some 230 million years ago, the first dinosaur
was presumably a small-bodied, fleet-footed predator. Then two major
groups of dinosaurs, the gigantic species and the smaller duck-billed
grazers, evolved as plant eaters.
As for Falcarius, scientists are not sure what it ate, meat or plants
or both, and they suspect that the transition extended over several
But with Falcarius, Dr. Sampson said, "we have actual fossil evidence
of a major dietary shift, certainly the best example documented among
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