It is endemic to the north-central Democratic Republic of the Congo and only known from its type locality, Buta.

[1][2][3] The specific name gastoni honours Gaston-François de Witte,[3] a Belgian colonial administrator and naturalist[4] who scrutinized the types.

The finger and toe tips may be slightly dilated but are not expanded into discs.

The dorsal skin is rugose and warty; the scapular region bears a pair of prominent glands.

The throat has finely stippling of dusky specks, which coalesce to form irregular patches on the lips and a band across the chest.