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By Patricia Reaney
LONDON
(Reuters) - A volcanic eruption in northern China 150 million
years ago has provided scientists with a treasure trove
of fossils showing that salamanders originated in Asia,
scientists said Wednesday.
Hot
ash from the volcano spewed into a small lake near Fengshan
in Hebei Province about 250 miles north of Beijing and petrified
more than 500 salamanders in the amphibian equivalent to
Pompeii.
The
remains are 85 million years older than previous specimens
and fill a huge gap in fossil records -- an important tool
for understanding the evolution of the mythical lizard-like
creatures.
"The
simple, take-home message is that there is an Asian origin
for all salamanders," said Neil Shubin of the University
of Chicago.
From
what they have uncovered Shubin and Ke-Qin Gao, of the American
Museum of Natural History in New York, believe that salamanders
evolved earlier than previously thought and that the creatures
have changed little since they roamed the Earth alongside
dinosaurs.
"For
the first time we have a large supply of salamander samples
to understand their evolution," Gao said in a telephone
interview.
The
fossils, described in the latest edition of the science
journal Nature, show all the stages of the lives of the
amazing creatures that survived the event that wiped out
the dinosaurs. Ironically, and to the puzzlement of scientists,
they are disappearing today.
Salamanders
are one of three types of amphibians but Gao said they are
the least understood. They are a type of living fossil because
they have such a primitive body type yet have the poorest
fossil record.
"Now
we not only have the earliest fossil record but also a very
large sample and several kinds of salamander all in one
site," Gao explained.
One
of the most intriguing features about salamanders is how
little they have changed and how different types of the
creatures evolved the same features independently in a process
called parallel evolution.
The
fossils may shed some light on parallel evolution and could
help researchers understand another perplexing feature about
the creatures -- how the adult animal can retain juvenile
characteristics.
"Whether
you look at a salamander you find under a rock in the local
forest preserve or in a rock in China dating back 150 million
years, they look alike. In fact, they look alike in great
detail -- the bones in their wrists are the same, the way
their skulls are formed -- intricate details are the same,"
Shubin added in a statement.
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