The males have a paired internal vocal sac and three short ridges of small black spines along the inner surface of the first manual digit.

These contain arteries and are thought to increase the surface area for the purpose of absorbing oxygen (comparably to external gills of the aquatic stage), which is useful as the male stays with his eggs for an extended period of time after they have been laid in the water by the female.

The hairy frog is also notable in possessing retractable "claws", which it may project through the skin, apparently by intentionally breaking the bones of the toe.

This type of natural weaponry appears to be unique in the animal kingdom, although the Otton frog possesses a similar "spike" in its thumb.

[9] It is found in Cameroon, Democratic Republic of the Congo, Equatorial Guinea, Gabon, Nigeria, and Angola, where it inhabits fast-flowing rivers in forests and agricultural lands that retain some cover (for example, plantations).