Two new species of lemur have been found in Madagascar, bringing the number of known species to 49.
Microcebus lehilahytsara is little bigger than a mouse. (Photo: Robert Zingg)
German and Malagasy scientists made the discovery by analysing the genetic make-up of wild lemurs.
Lemurs are considered the most endangered of all primates and live only on Madagascar which has evolved in isolation for 165 million years.
As a result, the island is now home to mammals, birds and plants that exist nowhere else on our planet.
The first new species is a giant mouse lemur known as Mirza zaza. It has a long bushy tail and is about the size of a grey squirrel.
Until now, scientists believed only one type of giant mouse lemur existed, split into two populations in the west and the north of the island.
But morphological, genetic and behavioural data shows they are in fact distinct species which diverged about two million years ago.
The second newly discovered species is a type of mouse lemur, of which nine species are now known.
Lemurs are the closest living analogs to our ancient primate ancestors who lived about 55 million years ago
One-third of species are extinct
Remaining species are under threat from hunting and habitat destruction
Microcebus lehilahytsara, or Goodman's mouse lemur, lives in eastern Madagascar's rainforest. It is little bigger than a mouse, with short, rounded ears and a white stripe on its nose.
"It is simply remarkable that M. lehilahytsara was obtained at Andasibe, a protected area of forest that is considered one of the best known sites on the island and is the most heavily visited by ecotourists," said Steve Goodman, a scientist with WWF and The Field Museum in Chicago, after whom the lemur is named.
"The fact that such an area holds a primate previously unknown to science underscores how much still needs to be done to document the biota of this extraordinary island."
The findings by scientists at the German Primate Centre (DPZ) and the University of Göttingen are described in the current issue of the journal Primate Report.