Smallest primate
Microcebus berthae, Madame Berthe's mouse lemur
Madagascar ()

The smallest true primate (excluding tree shrews, which are normally classified separately) is the Madame Berthe's mouse lemur (Microcebus berthae), which was discovered in 1992 in the deciduous forests of Menabe in western Madagascar. It has a head-body length of 9–9.5 centimetres (3.5–3.7 inches), a tail length of 12–14 centimetres (4.7–5.5 inches) and an average weight of 30.6 grams (1.1 ounces).

Owing to their similar appearance and diminutive proportions, the Madame Berthe's mouse lemur was long mistaken for the pygmy mouse lemur, aka Peter's mouse lemur (Microcebus myoxinus), which lives in the same region, but genetic and morphometric studies have subsequently distinguished the two species.

The lemur is named after the Madagascan conservationist and primatologist Berthe Rakotosamimanana (1938–2005).