Adult: Species description based on Savage (2002). A large treefrog (males to 81 mm, females to 77 mm). Females have a pouch on the dorsum in which they brood their young. Dorsal: Dorsal coloration varies from light to dark brown. Barring is present along the upper lip and on the upper surfaces of the arms and legs. Individuals can change color and are usually lighter during the day. The dorsal surface is smooth, except for a number of dark ridges that occur in transverse rows down the back. Ventral: The ventral surface is light brown, except for the throat, which is dark. In some individuals, the ventral surface has a pinkish cast. Concealed surfaces: The rear surfaces of the thighs are dark brown. Distinguishing characteristics: The horn-shaped points above the eyes are unique to this species. Eye: The eye is dark brown at the edges, lightening to yellow or green near the center.
Breeding season: Males call from high in trees (Duellman 1983, Savage 2002). Egg: Eggs are large, and clutch sizes are small (less than 10 eggs, Duellman 1983, Wassersug and Duellman 1984). Metamorph juvenile: Eggs develop directly into small froglets (Duellman 1983, Wassersug and Duellman 1984).
Habitat: Lowland and premontane forest to about 1000 m. Ecology: Gastrotheca cornuta generally lives high in the canopy (Savage 2002). Call: A loud "bop" (Savage 2002). Type locality: Cachabé (Ecuador)