Günther's Black Snake, Bothrolycus ater, is a poorly-known colubrid snake from central Africa. It is the only member of the genus, Bothrolycus. This snake is notable as one of the few snakes with notable sexual dimorphism (males have 17 scale-rows, females have 19), as well as possessing a small pit anterior to the eye. While superficially similar to the thermal pits of vipers, the function remains unknown. Found in Cameroon, Equatorial Guinea, Gabon and the Democratic Republic of Congo (Zaire).