Critically Endangered (IUCN 3.1)|Critically endangered
Gerp's mouse lemur (Microcebus gerpi) is a species of mouse lemur known only from the Sahafina forest in eastern Madagascar, near Mantadia National Park. Its discovery was announced in 2012 by a German and Malagasy research team. Based on genetic studies, measurements, and photos, the research team confirmed that Gerp's mouse lemur was an undescribed species, distinct from Goodman's mouse lemur, which is found 58 kilometers (36 mi) away. Gerp's mouse lemur is significantly larger, weighing on average 68 grams (2.4 oz), compared to Goodman's mouse lemur, which weighs approximately 44 g (1.6 oz). Jolly's mouse lemur, which is its closest relative and a neighbor to the south, is comparably large, but differs in tail length and genetics. Because it is a recently discovered species, nothing 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.