The Lavasoa dwarf lemur (''Cheirogaleus lavasoensis'') is a small,

nocturnal Nocturnality is an ethology, animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatures generally have ...

strepsirrhine Strepsirrhini or Strepsirhini (; ) is a Order (biology), suborder of primates that includes the Lemuriformes, lemuriform primates, which consist of the lemurs of Fauna of Madagascar, Madagascar, galagos ("bushbabies") and pottos from Fauna of A ...

primate Primates are a diverse order (biology), order of mammals. They are divided into the Strepsirrhini, strepsirrhines, which include the lemurs, galagos, and lorisids, and the Haplorhini, haplorhines, which include the Tarsiiformes, tarsiers and ...

and a

species In biology, a species is the basic unit of Taxonomy (biology), 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 ...

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 ...

that is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found els ...

to three small, isolated patches of forest on the southern slopes of the

Lavasoa Mountains Lavasoa-Ambatotsirongorongo Mountains are a mountain chain in southern Madagascar. They are situated in the municipalities of Sarasambo, Ankaramena, Ranopiso and Analapatsy, 30 km west of Fort Dauphin. They are composed of three peaks: #Grand ...

in southern

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 ...

. Fewer than 50 individuals are thought to exist. Its habitat lies in a transitional zone between three

ecoregions An ecoregion (ecological region) or ecozone (ecological zone) is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than a biogeographic realm. Ecoregions cover relatively large areas o ...

: dry spiny bush, humid littoral forest, and humid forest. First collected in 2001 and thought to be a subpopulation of the furry-eared dwarf lemur (''C. crossleyi''), it was not formally described until 2013. It is one of six species of

dwarf lemur The dwarf lemurs are the lemurs of the genus ''Cheirogaleus''. All of the species in this genus, like all other lemurs, are native to Madagascar. Description Measuring 19–27 cm in body length with a tail about 16–17 cm, they are ...

, though the research that identified it also suggested the existence of many more new species.

Taxonomic history

The Lavasoa dwarf lemur belongs to the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

''Cheirogaleus'' (

s) within the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Cheirogaleidae The Cheirogaleidae are the family of strepsirrhine primates containing the various dwarf and mouse lemurs. Like all other lemurs, cheirogaleids live exclusively on the island of Madagascar. Characteristics Cheirogaleids are smaller than the ...

. Between October 2001 and December 2006, researchers collected ten mature adults (five male and five female) along with six immature individuals. The lemurs were released after they were measured and small tissue samples were taken from their ears. The

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 ...

(AH-X-00-181) was an adult male, captured, recorded, and released at Petit Lavasoa on 10 October 2001. The analysis was published in 2013 by Dana Thiele and Andreas Hapke of Johannes Gutenberg University and Emilienne Razafimahatratra of the University of Antananarivo. In the two decades prior to 2013, only two dwarf lemur species were known, but in 2000 primatologist

Colin Groves Colin Peter Groves (24 June 1942 – 30 November 2017) was a British-Australian biologist and anthropologist. Groves was Professor of Biological Anthropology at the Australian National University in Canberra, Australia. Education Born in Engla ...

raised the number to seven based on morphological data acquired from museum samples. However, in 2009 and 2011, two of these new species were rejected. The Lavasoa dwarf lemur, named for the

in southern Madagascar, became the sixth known species in 2013 when it was differentiated from the furry-eared dwarf lemur (''C. crossleyi'') through analyses of

mitochondrial A mitochondrion (; ) is an organelle found in the cells of most Eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is us ...

and

nuclear material Nuclear material refers to the metals uranium, plutonium, and thorium, in any form, according to the IAEA. This is differentiated further into "source material", consisting of natural and depleted uranium, and "special fissionable material", con ...

performed by a team of German and Malagasy researchers. Furthermore, their research suggested the existence of three more new dwarf lemur species that they provisionally named ''Cheirogaleus'' sp. Ranomafana Andrambovato, ''Cheirogaleus'' sp. Bekaraoka Sambava, and ''Cheirogaleus'' sp. Ambanja, based on the regions the samples were collected. The Lavasoa dwarf lemur is most closely related to ''C.'' sp. Ranomafana/Andrambovato. The authors speculated that even greater species diversity may be found among dwarf lemurs by future studies due to their large geographic range and the great

genetic distance Genetic distance is a measure of the genetic divergence between species or between populations within a species, whether the distance measures time from common ancestor or degree of differentiation. Populations with many similar alleles have s ...

exhibited within the genus.

Description

The Lavasoa dwarf lemur is a small lemur, weighing and measuring in length. Its eyes are surrounded by black fur that forms a ring around the eyes. The black fur runs from the eyes to the animal's pointed nose. The rest of the fur on its head is reddish-brown, except for a thin strip between the eyes which is lighter in color. The back of the Lavasoa dwarf lemur is reddish-brown at the neck which fades to gray-brown at the posterior end. The underside of the lemur is a cream color. Hands and feet are grey-brown in most individuals, but reddish-brown in a minority. Throughout the animal exhibits dichromatic hairs with gray bases. The Lavasoa dwarf lemur can be distinguished from the furry-eared dwarf lemur by its wider ears and smaller head. It can be distinguished from its closest relative, ''Cheirogaleus sp.'' Ranomafana Andrambovato, by these two traits plus a shorter tail. The coloration patterns are very similar between all three species. This coloration pattern contrasts with Lavasoa dwarf lemur's closest geographic neighbors, the greater dwarf lemur (''C. major'') and the

fat-tailed dwarf lemur The fat-tailed dwarf lemur (''Cheirogaleus medius''), also known as the lesser dwarf lemur, western fat-tailed dwarf lemur, or spiny forest dwarf lemur, is endemic to Madagascar. Hibernation Recent research has shown that ''C. medius'' hibernat ...

(''C. medius'').

Behavior

Like other dwarf lemurs, the Lavasoa dwarf lemur is

and

arboreal Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally, but others are exclusively arboreal. The habitats pose num ...

, living in the upper canopy of the forest. During the dry winter, they

hibernate Hibernation is a state of minimal activity and metabolic depression undergone by some animal species. Hibernation is a seasonal heterothermy characterized by low body-temperature, slow breathing and heart-rate, and low metabolic rate. It most ...

for several months. Little is known about their behavior because they are primarily active during the rainy season, at which time the forests become challenging for scientists to reach.

Distribution and habitat

The Lavasoa dwarf lemur is

to the southern slopes of the Lavasoa Mountains in the

Anosy Region Anosy is one of the 22 regions of Madagascar. It is located in the southeast of the country, on the eastern side of what was once the Toliara Province. The name ''Anosy'' means "island(s)" in Malagasy. Due to a strategic sea route running al ...

of Madagascar. It is only found in three small fragmentary forests (Grand Lavasoa, Petit Lavasoa, and Ambatotsirongorongo), located within a transitional zone between dry spiny bush, humid littoral forest, and humid forest. Despite containing some flora from the drier regions, its habitat general resembles humid forests.

Conservation status

The three forest fragments in which the Lavasoa dwarf lemur is found used to be a part of a larger forest that once covered the southern range of the Lavasoa Mountains, as illustrated by

aerial photographs Aerial photography (or airborne imagery) is the taking of photographs from an aircraft or other airborne platforms. When taking motion pictures, it is also known as aerial videography. Platforms for aerial photography include fixed-wing air ...

from 1957. These remaining forest fragments are contained within a new protected area around Ambatotsirongorongo (Nouvelle Aire Protégée Ambatotsirongorongo), which is part of the national service of protected areas (Système des Aires Protégées de Madagascar, SAPM). Thiele ''et al''. estimated that 50, maybe fewer, Lavasoa dwarf lemurs live within this range.

References

{{Taxonbar, from=Q14376067 Mammals described in 2013 Dwarf lemurs