NEW RODENT SPECIES IN LAOS?

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March 10, 2006

 

 

 

http://www.sciam.com/article.cfm?chanID=sa003 & articleID=0004626C-B176-1410-B1768\

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Laotian Rodent Proves Living Fossil

 

 

 

Image: COURTESY OF MARK A. KLINGER

 

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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" It's the coelacanth of rodents, " Dawson says, referring to the

ancient fish believed extinct until a live specimen was hauled from

the depths by South African fishermen. " One of the beautiful parts of

this discovery was that we were able to correctly predict that

Laonastes would have four roots in its molars just as in Diatomys. "

 

The rock rat represents a rare opportunity to compare assumptions

derived from the fossil record and an actual living specimen to

determine overall accuracy of the techniques involved, the scientists

argue. It also represents tantalizing support for the theory that many

mammals evolved in Asia and later colonized other continents, as its

closest living relative is the gundis--a guinea pig-like rodent of

northern Africa.

Ultimately, kha-nyou provides a compelling argument for preservation

efforts in Southeast Asia, joining tree shrews, flying lemurs and

tarsiers as remnant populations of ancient mammal families in the

region. " Laonastes is not the only new organism to be discovered in

southeastern Asia, " Dawson adds. " The highest priority must be given

to preserving this unique biota and especially Laonastes while it is

still possible. " --David Biello

 

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SCIENCE NEWS

May 12, 2005

Scientists Discover New Rodent Family in Asian Market

 

Image: R. TIMMINS/WCS

 

A routine shopping trip in a market in central Laos has yielded much

more than a good bargain. Scientists have discovered a unique

long-whiskered rodent representing a previously unknown mammal family.

The locals were already familiar with the species, which they had

dubbed Kha-Nyou. But when Robert Timmins of the Wildlife Conservation

Society first spied it for sale on a table at the hunters market, he

immediately recognized it as exceptional. Timmins and his colleagues

at the World Wildlife Fund in Thailand soon gathered other specimens

from hunters and recovered bone fragments from the creature in an owl

pellet. Genetic analysis and a morphological study of the animal's

skull and bone structure indicate that Kha-Nyou represents a new

family, genus and species--one that diverged from other rodents

millions of years ago.

The creature, which scientists have renamed Laonastes aenigmamus,

seems to prefer forest cover and limestone outcroppings for its living

quarters and it is believed to be a nocturnal vegetarian. " To find

something so distinct in this day and age is just extraordinary, "

Timmins remarks. " Skeptics might say that if we are still discovering

such amazing new animals, why are people worried about wildlife loss.

But of course it is an indication of how little we know and a window

onto what we could be losing without ever knowing. " The discovery is

detailed in a paper published in a recent issue of the journal

Systematics and Biodiversity. --Sarah Graham