Latest Re: 'True missing link' fossil false?
gread at ACTRIX.GEN.NZ
Sat Apr 8 13:17:19 CDT 2000
National Geographic invited me to e-mail this to a friend (or two). The
surprise in the 'Archaeoraptor' fossil panel report (Nat. Geo. News, 7
April 2000) seems to be that several specimens may have contributed to
Geoff Read <gread at actrix.gen.nz>
You can see the complete version of this story complete with photos and
related links at
ARCHAEORAPTOR A COMPOSITE, PANEL OF SCIENTISTS DETERMINES
A group of scientists has confirmed that the fossil specimen
known as Archaeoraptor is a combination of at least two different
animals. They based their finding on a comparison of the
fossil with that of a new predatory dinosaur from China.
The two fossil specimens were compared and scrutinized on
Tuesday, April 4, by a panel of paleontologists and ornithologists,
headed by Hans-Dieter Sues, vice-president of collections
and research at the Royal Ontario Museum. Sues also is a
member of the National Geographic Society's Committee for
Research and Exploration.
The team concluded that the specimen is a composite of at
least two different animals. The tail clearly belongs to
the small predatory dinosaur, a dromaeosaur. The left and
right femurs are part and counterpart of each other, as
are the other leg bones, but the bones may represent a combination
of several specimens. The trunk region, shoulder girdle,
forelimbs and skull of the Archaeoraptor specimen do indeed
represent an animal new to science. This animal may have
implications for the early evolution of birds, but its relationship
to other primitive birds has not been determined, Sues said.
The Archaeoraptor specimen, unveiled at a National Geographic
Society news conference last October, was originally believed
to be a key species representing the evolutionary transition
from dinosaurs to birds.
Late last year, however, Chinese paleontologist Xu Xing
raised the question of the possibly composite nature of Archaeoraptor
after discovering that the supposed tail of the Archaeoraptor matched that
of a small predatory dromaeosaur from the same unit of rock in China.
In order to determine for certain whether the Archaeoraptor
was a composite and whether the fossil included any parts
of genuine significance, National Geographic convened the
panel of scientists. Besides Sues, the panel included James
Clark, assistant professor at George Washington University;
Catherine Forster, assistant professor, State University
of New York, Stony Brook; Mark Norell, chairman of the division
of paleontology, American Museum of Natural History; and
Storrs Olson, curator in the division of birds, National
Museum of Natural History.
Xu Xing of the Chinese Institute of Vertebrate Paleontology
and Paleoanthropology also was present at the session. Stephen
Czerkas, codirector of the Dinosaur Museum in Blanding,
Utah, presented the results of his own study of the two
fossils and his conclusion that Archaeoraptor was a composite.
PURCHASED ON OPEN MARKET
Based on information available last year, Archaeoraptor
was included in an article in the November 1999 National
Geographic and an exhibit at the National Geographic Society's
Explorers Hall. The fossil, which came from Early Cretaceous
rocks in Liaoning province, China, had been purchased on
the open market in the United States for the Dinosaur Museum.
Even before the fossil's origins were questioned by Xu Xing,
the Czerkases had decided to return it to China.
Regardless of this week's conclusion, most scientists have
been convinced for some time that birds descended from small,
meat-eating dinosaurs. They base the theory on a wealth
of fossil evidence from many locations around the world.
Source: Environmental News Network
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