Nilopegamys

The Ethiopian amphibious rat, also known as the Ethiopian water mouse (Nilopegamys plumbeus), is an insectivorous and semiaquatic species of rodent in the monotypic genus Nilopegamys of the family Muridae. There has only been one known specimen. It was found along the Lesser Abay River near its source at an altitude of 2600 m in the highlands of northwestern Ethiopia in 1928. N. plumbeus is considered to be the most aquatically adapted African murid; its unusually large brain is thought to be one consequence of this lifestyle. The species is considered to be critically endangered or possibly extinct, since its habitat has been severely damaged by overgrazing and monoculture.