With additional field studies, coupled with DNA analysis, the species tally later increased to nine.
Now, in addition to the three new species, the researchers propose four more groups for possible species recognition.
If confirmed, these 4 would bring the total number of mouse lemur species to 16.
A new picture is emerging of a multitude of distinct mouse lemur species across the vast island, separated from one another by barriers such as major rivers and mountains, says Mayor, a former field specialist and correspondent for the National Geographic Society. (National Geographic News is part of the National Geographic Society.)
More to Worry About
Madagascar is a global species-diversity hot spot and the only place in the world where lemurs occur.
All lemurs are thought to share a common evolutionary ancestor that arrived on the island more than 60 million years ago.
Since then the lemur lineage has branched into a variety of shapes, sizes, and habitats.
Over 70 lemur species are now known. But almost all are endangered, mostly due to habitat loss as Madagascar's forests are cut down for subsistence farming or harvested for timber.
"Unlike their larger relatives, mouse lemurs are not hunted for food, due to their small body size, but they are just as at risk of going extinct because of their rapidly disappearing habitat," Mayor said. (See a photo-essay on the selling of wild animals as foodwarning: graphic content.)
Primatologist Robert Martin, now a provost at the Field Museum in Chicago, says that as the number of recognized species grows, so do conservation concerns.
Back when only two widespread species were recognized, mouse lemurs appeared to be in far less danger than some of their larger lemur relatives.
"Subdivision into 15 species means that some of the more localized forms may be far more vulnerable to extinction," Martin said.
But the new discoveries may be helping the conservation cause. Madagascar's president recently announced that the government would be tripling the total size of the island's protected areas to 14,826,000 acres (6,000,000 hectares).
"These small lemurs have become huge ambassadors for all things wild in Madagascar," Mayor said.
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