Blanchard Randrianambinina

Finding a new species may look easy on paper, the conservationist Jonah Ratsimbazafy says, but it takes a long, long time. He and his colleagues spent many a night in the jungle chasing after camouflaged hamster-size creatures hopping around the branches and brush. Their work paid off, though: after snagging 14 mouse lemurs, they were surprised to find they had a new species.

“This is great news,” said Dr. Ratsimbazafy, who leads the Study and Research Group on the Primates of Madagascar, an organization dedicated to lemur conservation. He said the discovery would “bring more attention to the forest.”

As part of a biodiversity survey in an understudied region of eastern Madagascar, the researchers gathered mouse lemurs with live traps and by hand. “Of course, they bite,” said Ute Radespiel, a conservation biologist and primatologist at the University of Veterinary Medicine in Hanover, Germany, laughing. “You’d keep all your digits, but that’s why we wear gloves.”

Dr. Radespiel, the lead author of a paper announcing the discovery in the journal Primates, is not new to this game. She has worked on mouse lemurs since 1995 and has been involved in describing six new species.

Madagascar is much more diverse than researchers initially thought. In the 1990s, scientists knew of just two species of mouse lemur. But with further exploration, a surprisingly complex web of biodiversity emerged. Eventually, researchers discovered nearly 100 lemur species, including 18 species of mouse lemur.



The research organization’s mouse lemur is the 19th species added to the list. The researchers have named it the GERP mouse lemur (Microcebus gerpi), after the French abbreviation for the primate research organization, to which all of the paper’s authors belong. Its brownish-gray body is about the size of a large mouse, and a characteristic white stripe runs between its large, protruding eyes.

After catching the unidentified lemur in the Sahafina forest, the researchers set out taking measurements, photographing it and collecting small tissue samples for genetic analysis at a lab in Germany. All of the animals were released soon after they were captured.

Initial measurements confirmed morphological differences between the new mouse lemur and other known species, and genetics further clarified the split. Dr. Radespiel performed standard phylogenetic analysis of three different mitochondrial DNA genes to clarify the animal’s taxonomic status.

The mouse lemur’s genetics show a sharp divergence from its nearest relatives. “We have a rather solid case,” Dr. Radespiel said. “It’s really, really different from its next neighbors, both the geographic ones and the taxonomic sister groups.”

Madagascar is the world’s fourth-largest island, but it is still a relatively restricted space. For such a small area — about four-tenths of 1 percent of the world’s land — the island is a startling cornucopia of biodiversity, including 20 percent of all described primate species.

“New species are still popping up whenever researchers go into areas not studied before,” Dr. Radespiel said. “This is not only the case for lemurs, but for new amphibians, reptiles and mammals.”

Many of Madagascar’s species are confined to small areas, often in patches the size of Jamaica or Cyprus. Researchers do not know why animal ranges in Madagascar tend to be so restricted, although speculation includes differences in altitude and vegetation and the island’s large rivers.

The newly found mouse lemur’s closest genetic relative, the Jolly’s mouse lemur, lives in a patch of forest just 30 miles away, but at a different altitude. At first glance, the species seemed to be the same; only a closer inspection revealed subtle morphological distinctions like a larger body and longer tail. In most previous studies, altitudinal differences were not investigated, suggesting that there could be other undiscovered species.

“I assume there’s still quite a few mouse lemurs to be found,” Dr. Radespiel said. “The map is still not filled — we don’t know what kind of diversity is out there in these forests.”

The idea of unknown species waiting to be discovered only increases conservationists’ sense of urgency about collecting more data and encouraging the protection of the forests. Making local communities aware of their unique natural heritage is the first order of business, Dr. Radespiel said: without their cooperation, conservation efforts will not get off the ground, she said.

This tract of the Sahafina forest is particularly vulnerable to exploitation because it is low-lying and more accessible for agriculture and hunting than the upland areas, conservationists say. While deforestation primarily threatens mouse lemurs, people capture the animals for food, too.

The hope is that an agreement will be reached with local people to set aside a certain proportion of the forest for conservation. People may assume that the same mouse lemurs occur all over the island, Dr. Radespiel said, or that they are common to many countries. (Mouse lemurs live only in Madagascar and the Comoros Islands.)

Dr. Ratsimbazafy said, “We want them to be proud of the forest.”

With populations of unique species living in such small, isolated communities, simply having a handful of national parks will probably not be sufficient for conserving all of Madagascar’s animals.

“It’s probably an illusion to say we can make sure not to lose all species,” Dr. Radespiel said, “but at least for species we know of and can use as a sort of flagship species, our hope is that we can slow down this process and maybe even bring it to a halt.”

In the meantime, the researchers hope their discovery will stir excitement among scientists locally and internationally, encouraging others to fill in the knowledge gaps and convince the Madagascan authorities of the worth of the island’s biodiversity.

“There are still treasures unknown in the forests of Madagascar,” Dr. Ratsimbazafy said. “The discovery is one step, but if the forests are gone the next day, that’s no good.”



An earlier version of this post, quoting a researcher, referred incompletely to mouse lemurs’ current habitat. They are found in both the Comoros Islands and in Madagascar, not only in Madagascar.