Gerp's mouse lemur (''Microcebus gerpi'') is a species of
mouse lemur
The mouse lemurs are nocturnal lemurs of the genus ''Microcebus''. Like all lemurs, mouse lemurs are native to Madagascar.
Mouse lemurs have a combined head, body and tail length of less than , making them the smallest primates (the smallest spe ...
known only from the
Sahafina Forest in eastern
Madagascar
Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...
, near
Mantadia National Park
Andasibe-Mantadia National Park is a 155 square kilometre protected area, located about 150 km east of Antananarivo, consisting principally of primary growth forest in Alaotra-Mangoro Region in eastern Madagascar. The park's elevation rang ...
. Its discovery was announced in 2012 by a German and Malagasy research team. The Sahafina Forest had not been studied until 2008 and 2009, when Groupe d'Étude et de Recherche sur les Primates de Madagascar (GERP)—a Malagasy-based research and conservation group for which the lemur is named—inventoried the forest's
lemur
Lemurs ( ) (from Latin ''lemures'' – ghosts or spirits) are wet-nosed primates of the superfamily Lemuroidea (), divided into 8 families and consisting of 15 genera and around 100 existing species. They are endemic to the island of Madaga ...
s.
Based on genetic studies, measurements, and photos, the research team confirmed the Gerp's mouse lemur was an undescribed species, distinct from
Goodman's mouse lemur, which is found away. Gerp's mouse lemur is significantly larger, weighing on average , compared to Goodman's mouse lemur, which weighs about .
Jolly's mouse lemur, which is its closest relative and a neighbor to the south, is comparably larger, but differs in tail length and genetics.
Because it is a recently discovered species, little is known about its behavior, communication, ecology, or reproduction. The species appears to be restricted to a small region of lowland evergreen rain forest, and is seriously threatened by
forest loss.
Evolutionary and taxonomic history

Gerp's mouse lemur was discovered by German and Malagasy members of the Malagasy organization Groupe d'Étude et de Recherche sur les Primates de Madagascar (GERP) in a previously unstudied lowland forest known as the Sahafina Forest in eastern
Madagascar
Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...
, near
Mantadia National Park
Andasibe-Mantadia National Park is a 155 square kilometre protected area, located about 150 km east of Antananarivo, consisting principally of primary growth forest in Alaotra-Mangoro Region in eastern Madagascar. The park's elevation rang ...
. The first recorded specimen (
holotype
A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of seve ...
) of the species was captured on 25 June 2009, and was released after genetic samples, measurements, and photographs were taken. At the time, it was not recognized as a distinct species of
mouse lemur
The mouse lemurs are nocturnal lemurs of the genus ''Microcebus''. Like all lemurs, mouse lemurs are native to Madagascar.
Mouse lemurs have a combined head, body and tail length of less than , making them the smallest primates (the smallest spe ...
. Two other
paratype
In zoology and botany, a paratype is a specimen of an organism that helps define what the scientific name of a species and other taxon actually represents, but it is not the holotype (and in botany is also neither an isotype nor a syntype). O ...
s were also measured and recorded, but no physical specimen was obtained by the publication of the initial study.
[
The discovery was published in the journal '']Primates
Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians (monkeys and apes, the latter includin ...
'' in 2012. The species was named after the research and conservation team that described it. Gerp's mouse lemur differed genetically and physically from all of its nearest neighboring mouse lemur species. Its tail is longer than its closest relative, Jolly's mouse lemur (''M. jollyae''), which lives further south and whose tail is 18% shorter. It also has a higher body mass () and is generally larger than Goodman's mouse lemur (''M. lehilahytsara''), which weighs about . Gerp's mouse lemur exhibits significant genetic differences from its northern neighbor, Simmons' mouse lemur (''M. simmonsi'').[
The genetics tests initially conducted focused on three different ]loci
Locus (plural loci) is Latin for "place". It may refer to:
Entertainment
* Locus (comics), a Marvel Comics mutant villainess, a member of the Mutant Liberation Front
* ''Locus'' (magazine), science fiction and fantasy magazine
** '' Locus Award ...
of mitochondrial DNA: a partial D-loop
In molecular biology, a displacement loop or D-loop is a DNA structure where the two strands of a double-stranded DNA molecule are separated for a stretch and held apart by a third strand of DNA. An R-loop is similar to a D-loop, but in this cas ...
region, ''MT-CYB
Cytochrome b is a protein that in humans is encoded by the ''MT-CYB'' gene. Its gene product is a subunit of the respiratory chain protein ubiquinol–cytochrome ''c'' reductase (UQCR, complex III or cytochrome ''bc''1 complex), which consis ...
'', and '' COII''. D-loop analysis suggested Jolly's mouse lemur was Gerp's mouse lemur's closest relative (forming a sister group
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree.
Definition
The expression is most easily illustrated by a cladogram:
Taxon A and ...
). All three tests showed the mouse lemurs sampled from Sahafina formed a monophyletic clade (an exclusive family group) and the species was sufficiently distinct from other mouse lemurs. The authors concluded both the molecular and morphological differences supported the declaration of a new species based on the phylogenetic species concept
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sex ...
and a more conservative "integrative taxonomic approach".[
]
Anatomy and physiology
Among mouse lemurs, Gerp's mouse lemur is larger-bodied and has a long tail, which can be used to store fat. The fur is darker on its back, which is brownish-gray with a broad reddish line down the middle, compared to the front, which varies from a light gray to creamy white and extends from the throat to the genitals. The outer arms and legs contrast the rest of the body with their darker color, and the fingers have sparse, whitish-gray fur. The head is reddish in color, with darker brown surrounding the eyes and a noticeable white stripe across the nose and between the eyes. Its ears are prominent, yet small, with dark brown edges. The tail is covered in dense, long, brownish-gray fur. The undercoat is short and dense, while the guard hair
Guard hair or overhair is the outer layer of hair of most mammals, which overlay the fur. Guard hairs are long and coarse and protect the rest of the pelage (fur) from abrasion and frequently from moisture. They are visible on the surface of the fu ...
s are sparser. The skin visible on the hands and feet is colored pinkish-brown.[
Gerp's mouse lemur weighs around and has a tail length of approximately . It is a large-bodied mouse lemur, and belongs to a group of large mouse lemurs (weighing more than ), including four eastern species—Simmons' mouse lemur, Jolly's mouse lemur, the ]northern rufous mouse lemur
The northern rufous mouse lemur (''Microcebus tavaratra''), northern brown mouse lemur, or Tavaratra mouse lemur is found in northern Madagascar from the Ankarana Special Reserve in the west to the Manambato River in the northeast, and up to th ...
(''M. tavaratra''), and MacArthur's mouse lemur (''M. macarthurii'')—as well as six species of western mouse lemur: Claire's mouse lemur (''M. mamiratra''), Danfoss' mouse lemur (''M. danfossi''), the Bongolava mouse lemur (''M. bongolavensis''), the golden-brown mouse lemur (''M. ravelobensis''), the gray mouse lemur
The gray mouse lemur (''Microcebus murinus''), grey mouse lemur or lesser mouse lemur, is a small lemur, a type of strepsirrhine primate, found only on the island of Madagascar. Weighing , it is the largest of the mouse lemurs (genus ''Microceb ...
(''M. murinus''), and the reddish-gray mouse lemur (''M. griseorufus''). Most of these larger mouse lemur species have a long tail, as does Gerp's mouse lemur, with the exception of Jolly's mouse lemur and the gray mouse lemur. Its ears are small (measuring ), which conforms with that of other rainforest mouse lemur species, in contrast to larger-eared mouse lemurs of the dry, western forests (averaging ). As with all mouse lemurs, no body mass differences could be discerned between the sexes. However, larger samples are needed to confirm this.[
]
Behavior
No data are available concerning the behavior, communication, ecology, or reproduction of the Gerp's mouse lemur, although such data may help support its species status.[
]
Distribution and habitat
Gerp's mouse lemur has only been identified in the Sahafina Forest in eastern Madagascar, about east of Mantadia National Park, south of the city of Toamasina
Toamasina (), meaning "like salt" or "salty", unofficially and in French Tamatave, is the capital of the Atsinanana region on the east coast of Madagascar on the Indian Ocean. The city is the chief seaport of the country, situated northeast of it ...
, and from the Indian Ocean
The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by ...
. The forest fragment is about and is surrounded by secondary forest
A secondary forest (or second-growth forest) is a forest or woodland area which has re-grown after a timber harvest or clearing for agriculture, until a long enough period has passed so that the effects of the disturbance are no longer evident. ...
growing in areas previously cut for rice cultivation (known locally as ''savoka'').[
The Sahafina Forest ranges from above sea level, whereas nearby Mantadia National Park, home of its closest neighboring mouse lemur population (Goodman's mouse lemur), ranges from above sea level. No major rivers separate these highland and lowland forests and their respective mouse lemur populations. The initial study did not conclude whether the large Rianila River or one of the smaller rivers—the Ivonoro and Onibe—further north acts as a species boundary between Gerp's mouse lemur and Simmons' mouse lemur (''M. simmonsi'') to the north. Approximately the south lies the Mangoro River, a very large river that acts as a biogeographic barrier for many species. In 2010, a genetically distinct form of mouse lemur was sequenced from Marolambo, south of the river. The geographic range of Gerp's mouse lemur is unlikely to extend south of this river, but more studies are needed to confirm this. In total, the area between the rivers to the north and south, the highlands to the west, and the ocean to the east is no larger than (smaller than the island of Puerto Rico) and this is the likely extent of its geographic range.][
]
Conservation status
There are no protected area
Protected areas or conservation areas are locations which receive protection because of their recognized natural, ecological or cultural values. There are several kinds of protected areas, which vary by level of protection depending on the ena ...
s within the known geographic range of Gerp's mouse lemur. Because it lives in lowland forests, which are more likely to be converted into agricultural land relative to highland rainforests, it faces an elevated conservation risk. Of the of its potential geographic range, only very small parts remain forested.[
]
References
{{Taxonbar, from=Q1514699
Mouse lemurs
Endemic fauna of Madagascar
Mammals of Madagascar
Critically endangered fauna of Africa
Mammals described in 2012