Calyptocephalella gayi

Calyptocephalella gayi (syn. Caudiverba caudiverba), the helmeted water toad, Chilean helmeted bull frog or wide-mouth toad, is the sole species of the genus Calyptocephalella in the family Calyptocephalellidae. The only other members of this family are Telmatobufo. The helmeted water toad is found in central Chile, and possibly adjacent west-central Argentina. This very large toad weighs up to 0.5 kg (1.1 lb). It is aquatic and found in deep ponds and small reservoirs. It is threatened by capture for human consumption, habitat loss, pollution, and introduced trout. It is occasionally captured for herpetoculture. This very large species can reach a snout–to-vent length of up to 12 cm (4.7 in) in males and 32 cm (13 in) in females. The maximum weight is 0.5 kg (1.1 lb). The tadpoles are also unusually large at up to 15 cm (5.9 in) long. These toads are colored yellow, brown, and green, with light green in mature specimens, while the oldest are gray, or have gray patches on a dark background.