Gerp’s Mouse Lemure, Microcebus gerpi

Gerp’s Mouse Lemur (Microcebus gerpi) can only be found near Mantadia National Park in the Sahafina forest of eastern Madagascar. A German and Malagasy research team publicized its discovery in 2012. The Sahafina forest was not researched until 2008, when Groupe d’Étude et de Recherche sur les Primates de Madagascar(GERP), a Malagasy-based research and preservation group from which the lemur’s name derives, preformed a study and “inventory” of all the lemurs in the forest.

The researchers conducted genetic studies, measurements, and captured photographs of Gerp’s mouse lemur, confirming that it was an undiscovered species and separate from Goodman’s mouse lemur that was found 36 miles away. There is no information about Gerp’s mouse lemur pertaining to its ecology, reproduction habits, behavior, or communication, but it is limited to a small area of lowland evergreen rainforest and is vulnerable to habitat loss.

The range of Gerp’s lemur is very small, reaching approximately six square miles. There are many rivers running though the Sahafina forest, and it has not been concluded that the Rianila River, or its sister rivers the Ivonoro and Onibe, are boundaries for the Gerp’s lemur range. It is though that the river Marolambo may be the extent of its range, creating an area that is 2,900 square miles large. Of this small estimated range, only portions remain as viable forest habitat, as the rest will most likely be converted in to farmlands for rice known locally as savoka and other materials.

The first Gerp’s Mouse Lemur found, or the holotype was captured on June 25, 2009 and released after samples, measurements, and photographs were taken. Two other individuals were studied but were not taken in order to study. The discovery was first published in Primates in 2012.

It differs greatly from all other mouse lemur species in its range. Its closest kin, Jolly’s mouse lemur (M. jollyae)  which lives farther south, has a much shorter tail. It is also significantly larger than Goodman’s mouse lemur (M. lehilahytsara) weighing an average of 2.4 ounces.

Using genetic testing methods and looking at three different loci of mitochondrial DNA in three different mouse lemurs, scientists concluded that Jolly’s mouse lemur was the closest kin to Gerp’s mouse lemur and these two comprised a new sister group. Further testing revealed that all three lemurs comprise a monophyletic clade, or distinct family group, that is separate from other mouse lemurs. With this information, the researchers determined the molecular and morphological differences gave reason to classify the three lemurs as a new species.

Gerp’s mouse lemur is quite large for its size, reaching a tail length of up to 5.7 inches, which can be used to retain fat. It has small ears, as is typical for rainforest dwelling mouse lemurs, and there is no visible weight difference between males and females. The fur is grayish brown on the back with a thick, red line running down the spine. The ventral and frontal areas of the lemur’s fur are a much lighter white or gray color. The legs and arms are dark, and the “fingers” have little to no fur. The tail fur is incredibly long and burnished gray in color. The head is redder compared to the rest of the body, and each lemur has a visible white stipe running across the nose from eye to eye.  Currently, there is not enough information to give Gerp’s mouse lemur a conservation status.

Image Caption: Gerp’s mouse lemur (Microcebus gerpi): Paratype 03y09 fina (male). Credit: Blanchard Randrianambinina/Wikipedia(CC BY-SA 3.0)