Mouse lemur in the context of "Nocturnal"

Madame Berthe's mouse lemur (Microcebus berthae) or Berthe's mouse lemur is the smallest of the mouse lemurs and the smallest primate in the world; the average body length is 9.2 cm (3.6 in) and seasonal weight is around 30 g (1.1 oz). Microcebus berthae is one of many species of Malagasy lemurs that came about through extensive speciation, caused by unknown environmental mechanisms and conditions.

This primate is found chiefly in the Kirindy Forest in western Madagascar. After its discovery in 1992 in the dry deciduous forest of western Madagascar, it was initially thought to represent a rediscovery of M. myoxinus, but comparative morphometric and genetic studies revealed its status as a new species, M. berthae.

Lemurs, primates belonging to the suborder Strepsirrhini which branched off from other primates less than 63 million years ago, evolved on the island of Madagascar, for at least 40 million years. They share some traits with the most basal primates, and thus are often confused as being ancestral to modern monkeys, apes, and humans. Instead, they merely resemble ancestral primates.

Lemurs are thought to have evolved during the Eocene or earlier, sharing a closest common ancestor with lorises, pottos, and galagos (lorisoids). Fossils from Africa and some tests of nuclear DNA suggest that lemurs made their way to Madagascar between 40 and 52 mya. Other mitochondrial and nuclear DNA sequence comparisons offer an alternative date range of 62 to 65 mya. An ancestral lemur population is thought to have inadvertently rafted to the island on a floating mat of vegetation, although hypotheses for land bridges and island hopping have also been proposed. The timing and number of hypothesized colonizations has traditionally hinged on the phylogenetic affinities of the aye-aye, the most basal member of the lemur clade.

The pygmy mouse lemur (Microcebus myoxinus), also known as Peters' mouse lemur or dormouse lemur, is a primate weighing only 43–55 g (1.5–1.9 oz); it is the second smallest of the mouse lemurs. Its dorsal side is a rufous-brown colour, and creamy-white ventrally. It lives in dry deciduous forests of western Madagascar. It has been captured in the Tsingy de Bemaraha Nature Reserve, the Andramasy forests north of Belo sur Tsiribihina, and the border of heavily degraded deciduous forest and savanna at Aboalimena. It has also been found in other habitats, in mangroves in two localities.

Accounts and descriptions of this species are frequently confounded with those of Microcebus berthae, the smallest primate in the world. This is because specimens of M. berthae captured in Kirindy Forest, 60 km north of Morondava, were erroneously named M. myoxinus. Apparently, the rufous color of M. berthae (not described at the time) matched the description by Peter as M. myoxinus. Most articles on the web report information on M. myoxinus that correspond to studies made in Kirindy Forest on M. berthae.