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.[1] It is named after Dr. Ernst Williams, a friend and colleague of the scientist that described the species. It is a little studied species.
Males measure about 29mm 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.[2]
Its natural habitat is grassland and bushland on the summit of Sumaco.[2] Herpetological sources cite the altitude as being about 1900m (6,200feet),[1] [2] although other sources give maximum elevation of 3732m (12,244feet) to this mountain.[3] The volcano is in the Sumaco Napo-Galeras National Park.[3] Nevertheless, being restricted to a single location, the population is vulnerable stochastic processes.