Bothrolycus

Günther's black snake, Bothrolycus ater, is a species of poorly known colubrid snake endemic to 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, its function remains unknown.