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China Yields East Asia's Earliest Fossilized Frog



Xinhuanet
http://news.xinhuanet.com/english/2001-11/19/content_124207.htm
BEIJING, November 19, (Xinhuanet) -- Chinese scientists announced that they
have discovered the earliest frog fossils in Asia, whichthey believe would
solve the riddles in life evolution.

"Hundreds of Cretaceous amphibian fossils have been unearthed from a famous
dinosaur fossil beds at Sihetun in western part of Liaoning province since
2000," said Wang Yuan, expert from the Chinese Academy of Sciences (CAS),
"among them there is a rare fossilized frog dating back to 125 million years
ago."

The well-preserved specimen was then named "Sanyanlichan", documenting the
earliest and sole definite discoglossid fossil in Asia, and the second fully
articulated specimen of Mesozoic age known for the group, according to Wang.

  Wang, associate research fellow in the Institute of Vertebrate
Paleontology and Paleoanthropology in CAS, said that the specimen's most
prominent character is the nine presacral vertebrates, one more than any
extant frogs, indicating the early devolvement of frogs.

  He said that the finding would provide important evidence for the 
study
of amphibian evolution and biogeographic history. The study of amphibian is
of remarkable significance because the animal is a linkage between aquatic
and terraneous life forms, representing a great success in evolution.

  The family Discoglossidae, with "Sanyanlichan" as ancestor, is a group
of primitive frogs that includes the popular midwife toad (Alytes), males of
which carry eggs around their legs, and the fire-bellied toad (bombina), the
ventral surface of which is brightly colored for aposematic display.

  Fossil beds in western Liaoning Province gains its fame by producing
exceptionally well-preserved vertebrate fossils, including primitive birds,
feathered dinosaurs, mammals and other important fossils.

  "The finding also contributes to detect pollution degree of 
environments
by studying malformation rates of amphibian babies," said Wangyuan.

  According to Wang, the amphibians' fossils are difficult to be 
preserved
for its gentle bones, vulnerable to bacilli and other breakage.

  In Mesozoic times, when dinosaurs thrived, western part of Liaoning is
supposed to have a lot of water, and the eruption of volcano or suddenly
deposits of muddy stream procured the formation of frog fossils the
scientists unearthed today, experts said. Enditem

TAKAHASHI ,KAZUO
http://www.NetLaputa.ne.jp/~pantheon/
pantheon@kw.netlaputa.ne.jp