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.

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, near Mantadia National Park.

The first recorded specimen (holotype) of the species was captured on 25 June 2009, and was released after genetic samples, measurements, and photographs were taken.

[3] The genetics tests initially conducted focused on three different loci of mitochondrial DNA: a partial D-loop region, MT-CYB, and COII.

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.

In 2010, a genetically distinct form of mouse lemur was sequenced from Marolambo, 25 km (16 mi) 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 7,600 km2 (2,900 sq mi) (smaller than the island of Puerto Rico) and this is the likely extent of its geographic range.

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.