A new species of frog is described from Rondônia, Brazil. The new species shares most features with the genus Leptodactylus, although externally it resembles species of Physalaemus as much as species of Leptodactylus. The new species is provisionally assigned to the genus Leptodactylus, the definition of which must be expanded to include an areolate belly and small osteoderms lying above the vertebral column in order to accommodate the new species. The new species is known only from a single cerrado enclave in a predominantly Amazonian rainforest landscape.