More than 11 million years ago, a squirrel-like creature with long whiskers and hairy toes left proof of its existence in the fossil record of Southeast Asia. Now scientists have found a flesh-and-blood version, a Lazarus species, risen from the dead.
Scientists have no idea what the animal has been doing for the past 11 million years, or exactly where or how it lives today. The only specimens were found dead, in a market in Laos, destined to be somebody's dinner until two conservation biologists did a routine survey of the animals available for sale.
"Nobody has ever seen them alive," said Mary Dawson, a paleontologist who examined the rodent, and along with colleagues from France and China determined that it was a survivor from an ancient species scientists know only from the fossil record.
"I guess they are tasty little morsels," said Dr. Dawson, with the Carnegie Museum of Natural History in Pittsburgh.
Such finds are rare. In 1938, the discovery of a coelacanth, a fish from the age of the dinosaurs, made headlines around the world and set off an international search to find another specimen.
Dr. Dawson isn't sure the rodent found in Laos will spark the same kind of excitement. "If these were tigers or pandas or something spectacular, yes, but this is a small, dark, difficult-to-find, squirrel-like rodent."
When the rodent was discovered last year in Laos, researchers believed they had found an entirely new family of mammals. But Dr. Dawson and her colleagues compared the creature's remains with fossils from an extinct group of Southeast Asian rodents. They announced in today's edition of the U.S. journal Science that it is a survivor of this long-lost family. They say it likely eats plants, and possibly insects, and prefers rocky terrain.
Named Laonastes aenigmamus -- and also known as the Laotian rock rat -- the rodent is a striking example of what scientists call the "Lazarus effect," species long thought to be extinct that turn out to have survived, in some cases, over millions of years.
The coelacanth is perhaps the most famous of these. From fossils, researchers knew it lived about 80 million years ago. But they didn't know it had survived until 1938, when Marjorie Latimer, the curator of a small museum near Cape Town, South Africa, noticed an unusual fin protruding from a pile of fish on the deck of a local fishing boat.
She pulled it out, and later wrote that it was "the most beautiful fish I have ever seen, five feet long, and pale mauve blue with iridescent silver markings." Her reference books convinced her she had found a prehistoric species, and she was right. Her discovery was hailed as the most important zoological find of the century.
Scientists also believed that a species of peccary, a pig-like creature with a flat forehead, existed only in the fossil record. But in 1975, they found the animal in Paraguay. Turns out it was well known to the people who lived in the region, but not to Western scientists.
The discovery of a woodpecker thought to be extinct for more than 60 years made headlines last year and was also reported in the journal Science. The ivory-billed woodpecker was last seen in northeastern Louisiana in 1944. Researchers were ecstatic.
"It is like a funeral shroud has been pulled back, giving us the glimpse of a living bird, rising Lazarus-like from the grave," said Cornell University ornithologist Tim Gallagher, who saw the red-crested woodpecker.
In 2001, Australian researchers were thrilled to discover a tiny colony of rare insects they believed had been extinct for 80 years. The Lord Howe Island stick insect had been fodder for black rats who made their way to Lord Howe Island from a ship that ran aground in 1918.
These kinds of discoveries offer hope for other extinct plants and animals, such as the eelgrass limpet, a Canadian mollusk that hasn't been seen since 1929. They are tantalizing, but also frustrating. Dr. Dawson and her colleagues would love to know how the squirrel-like creature from Laos uses the bristles on its toes, for example, but it could be years before scientists find one alive, if they ever do.
In 1938, the museum curator who found the coelacanth notified a local professor with an interest in marine biology, but before he could get there, the fish was mounted and its innards were thrown out.
Professor J. L. B. Smith was able to confirm it was indeed a coelacanth, but was limited in what he could learn about the fish because it was hollow. A local newspaper reporter took a picture, which appeared in publications around the globe.
He began posting notices offering a reward for another coelacanth. Sea captains helped spread the word to local fishermen. A number of scientific expeditions went hunting for the ancient fish. But it was 14 years before two fisherman from the Comoro Islands, between Tanzania and Madagascar, found another one. In 2001, researchers found a colony off the coast of South Africa.
So far, no one has mounted a scientific expedition to hunt for the squirrel-like rodent, Dr. Dawson said. "If you are interested in rodents, it is really exciting. If you aren't . . ."
