Here is a Yahoo story at:
http://dailynews.yahoo.com/headlines/sc/story.html?s=v/nm/19990630/sc/science_dinosaurs_1.html
which has been repeated on a number of news sites, and is based on a
forthcoming NATURE article.
It seems the Chinese so-called "feathered dinosaurs" Caudipteryx and
Protarchaeopteryx, which were already younger than Archaeopteryx which
had advanced flight feathers, are now another 20 million years younger
than was first thought!
So what becomes of the many confident pronouncements that this
definitely was a feathered dinosaur?
There always were a minority of fossil bird experts like Feduccia who
maintained all along, because of the dating problem, that these were more
likely to be flightless birds, e.g.:
"`This is a very interesting find,' Feduccia said yesterday in an interview,
`but these fossils certainly look like flightless birds to me. I still believe that
although birds and dinosaurs may share a common ancestor, these fossils
more closely resemble many other feathered birds that later lost the ability
to fly, like ostriches and emus and kiwis. These fossils could well be
secondary flightless birds, and they certainly don't have to be dinosaurs.'"
(Perlman D., "Feathered Fossils Give Theory Wings: Find called proof
birds descended from dinosaurs," San Francisco Chronicle, Wednesday,
June 24, 1998.
http://www.sfgate.com/cgi-bin/article.cgi?file=/chronicle/archive/1998/06/24/MN26880.DTL)
I doubt that this "refugium" claim will hold water enough to save these
fossils as bird ancestors, but maybe those who have staked their reputation
on it will just keep on claiming it. A mainland area might be isolated for a
long time, but surely not for 20 million years! My guess is that these will be
reclassified as real birds, which lost their ability to fly, like the ostrich and
emu.
But in case there is any misunderstanding, please note that I personally
think it probable that birds were mediately created from a small, specially
prepared dinosaur line, but I have always doubted that these Chinese so-
called "feathered dinosaurs" had anything to do with it.
Steve
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Yahoo! News Science Headlines
Wednesday June 30 2:05 PM ET
Feathered Dinosaurs Are Not So Old, Research Shows
[...]
By Patricia Reaney
LONDON (Reuters) - Fossils of feathered dinosaurs and flowering plants,
considered an extremely important discovery when they were unearthed in
the Liaoning province in China, are not as old as scientists had thought,
researchers said Wednesday.
The discovery of fossil remains of species with distinctive feathers and
dinosaur features and the world's oldest flowering plant in China were
among the biggest finds in recent years.
Scientists had estimated the diverse fauna found in ancient lake beds in
Liaoning province were from the late Jurassic period -- about 140 million
years ago.
But new dating methods, published in the science journal Nature, of
sediment in which the fossils were found, puts them in the Cretaceous
period, 20 million years later than previous estimates.
"Probably no other story has created so much attention in the last couple of
years as the feathered dinosaurs or the world's oldest flowering plant or
some other aspect of this fauna from China," Carl Swisher III, of the
Berkeley Geochronology Center in California, said in a telephone
interview.
"Most people thought it was quite old but these dates directly associated
with the fauna suggest it is not as old as originally thought."
Swisher and his colleagues based their dates on measurements taken from a
mineral found in volcanic ash used in dating isotopic age.
In addition to accurately dating Caudipteryx and Protarchaeopteryx, two
species found in Liaoning that represent a link between dinosaurs and birds,
the research sheds new light on plant and animal evolution.
Zhexi Luo, of the Carnegie Museum of Natural History in Pittsburgh, said
any new information about the transition between the Late Jurassic and
Early Cretaceous periods, which saw the evolution of feathered dinosaurs,
flowering plants and the diversification of different mammal groups, is
important.
"The western Liaoning province and its neighboring areas are a refugium --
an isolated area in which a population survived much longer than elsewhere
-- for these relict (ancient animal or plant remains) lineages from a bygone
area," he said in a commentary in Nature.
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"We've got to have some ancestors. We'll pick those. Why? Because we
know they have to be there, and these are the best candidates. That's by
and large the way it has worked. I am not exaggerating." (Nelson G.,
interview with journalist Tom Bethell, The Wall Street Journal, December
9, 1986, in Johnson P.E., "Darwin on Trial," InterVarsity Press: Downers
Grove Ill., Second Edition, 1993, p76)
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