They Thought It Went Extinct 11 Million Years Ago

A mammal is "back from the dead"

By on March 13th, 2006 10:07 GMT
A team of scientists has discovered last year a weird rodent belonging to a new family of mammals, the first to be found in more than three decades. They found the animal for sale in market in Laos!

But now a group of researchers from the Carnegie Museum of Natural History have realized that the new mammal in fact belongs to a species thought to have been extinct for 11 million years. This is an amazing discovery since most similar examples of "back from the dead" mammals only go back around 10,000 years.

"It's the first time in the study of mammals that scientists have found a living fossil of a group that's thought to be extinct for roughly 11 million years. That's quite a gap. Previous mammals had a gap of only a few thousand to just over a million years," said study coauthor Mary Dawson.

They have identified the species based on its shape of the jaw and thanks to its highly characteristic molar teeth. The animal is called Diatomyidae and is a squirrel-sized rodent thought to have lived in southern Asia, central China, and Japan during the middle Tertiary period, between 34 million to 11 million years ago. But as a matter of fact it has never disappeared. The only difference between the fossils and the "living" specimen is that today's animal has slightly more pointed teeth.

According to Dawson, "it looks like possibly one of the things that's been changing in family is improved cutting of vegetation. But over 11 million years you'd expect some differences in the structures."

Scientists are yet to find a specimen in the wild. "Biologists need to get out there and find some living ones," Dawson said. This would help understanding their habits and determine why they moved from central Asia to the Indian subcontinent.

Photo Credit: R.J. Timmins/WCS Lao Program; The Natural History Museum, London

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