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Biologists have been throwing a big old scientist party celebrating the latest Lazarus Taxon—the Rat Squirrel—and all of nature is invited. Lazarus Taxon refers to a thing that once was thought dead, but turns out that it isn’t, like scientist parties.

The new excitement centers on a species from Laos that was first discovered in 1996 for sale in a meat market. By 1998 scientists had grabbed up a couple more dead samples, and in April of 2005 the little fellow was dubbed Laos Rock Rat. An apt name, really; they have a rat-like face with long whiskers and a generally gray color, and they’re from Laos. Everyone was happy, except that one scientist—paleontologist Mary Dawson. If he was such a new discovery, how did she know him? She’s a paleontologist—she knew him from his fossils.

The occurrence is a rare one called a Lazarus Taxon—it refers to these times where a species is discovered via fossils, named, cataloged, and pronounced dead, but then are later seen by other scientists who upgrade their condition to “alive”.

It turns out that around 11 million years ago there was a critter running around Asia that left his bones about for us to discover, date, and catalog. The bones were said to have come from the Squirrel Rat, another rat-faced, whiskered rodent with a slightly bushy tail. It was thought that all the Squirrel Rats were gone, but no—he’s just using a new name in the twenty-first century.

In 1938 a scientist named Marjorie Courtenay-Latimer noted some unusually burly looking blue fish among a fisherman’s catch, and thought they were neat. She picked one up and took it to her museum to see what it was, but couldn’t find it in any of the books. Rather than let her precious fish go bad and start stinking the place up, she sent it to a taxidermist and started showing it around. A friend of hers soon saw the similarity to a fish called a Coelacanth that was thought to have died out some 80 million years before. Immediately afterward, there was a bounty of 100 GBP to anyone who brought them more of fish … some people don’t take well to being told they’re wrong.

And again in 1997 a pair honeymooning in Indonesia on the island of Sulawesi saw a fish like a Coelacanth hanging in a market, but it was brown rather than blue. Curious, one of them bought the fish, and ended up testing its DNA. While not from the previously discovered population, they were a variant species that was also supposed to be dead.

Lesson learned: if you want to rediscover a species everyone thinks is dead, look to where the locals keep their cold cuts.