Pristimantis ernesti is a species of frog in the family Strabomantidae. It is endemic to the summit of Sumaco, a volcano in the Napo Province, Ecuador. Its common name is Ernest's robber frog. It is named after Dr. Ernst Williams, a friend and colleague of the scientist that described the species. It is a little studied species.

Description

Males measure about 29 mm in snout–vent length. Female size is unknown. The dorsum is coffee-coloured with dark gray markings, including a "W" mark on its upper back. Dorsal skin is glandular with prominent dorsolateral ridges.

Habitat and conservation

Its natural habitat is grassland and bushland on the summit of Sumaco. Herpetological sources cite the altitude as being about 1900 m, although other sources give maximum elevation of 3732 m to this mountain. The volcano is in the Sumaco Napo-Galeras National Park. Nevertheless, being restricted to a single location, the population is vulnerable stochastic processes.