Sunday, March 12, 2006

Laotian Rodent Proves Living Fossil


When wandering through a hunter's market in Laos, Robert Timmins of the Wildlife Conservation Society happened upon a previously unknown rodent. Called kha-nyou by locals--or rock rat--the long-whiskered and furry-tailed rodent was reputed to favor certain limestone terrain. Western scientists named it Laonastes aenigmamus or stone-dwelling enigmatic mouse--partially because a live specimen has never been collected--and thought the rock rat represented a new family of mammals. But new research reported in today's Science proves that Laonastes actually represents a fossil come to life.

Paleontologist Mary Dawson of the Carnegie Museum of Natural History and her team immediately recognized the strange rodent as a living member of a family thought to have been extinct for at least 11 million years: the Diatomyidae. Fossilized remnants of this group have been found throughout Asia with a distinctive jaw structure and molars. A new specimen of Diatomys discovered in June of last year in China bore an uncanny resemblance to Laonastes, including the same body size and tail span.

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