More specifically it is found in Burkina Faso, Central African Republic, Chad, Democratic Republic of the Congo, Gambia, Guinea, Guinea-Bissau, Ivory Coast, Kenya, Niger, Senegal, Tanzania, and Uganda.

It is uniformly blackish brown, to which the specific epithet, unicolor, refers.

Adults may attain a total length of 36.5 cm (14+1⁄4 in), with a tail 27 mm (1.1 in) long.

Rostral large, the portion visible from above nearly as long as its distance from the frontal.

Frontal 1½ to 1⅔ as long as broad, longer than its distance from the end of the snout, shorter than the parietals.