The Southern Darwin's frog inhabits the temperate forests of southern Chile and Argentina, latitudinally from Concepción to Aysén. Although they are very similar in appearance to its northern counterpart, this species is fully adapted to the terrestrial life within the native forest, not requiring bodies of water during any of the stages of its life cycle. This is possible because the neomelia of the Southern Darwin's frog is complete: the tadpoles reach the metamorphosis inside the male's vocal sac and are expelled, soon after that, to the forest as small froglets.The Southern Darwin's frog is an incredible animal. This species exhibits a high geographical variation of colouration and body size, although individuals never exceed 4 cm length. In the more seasonal environments of the Andes Mountain, these frogs are larger and are more commonly brown, while in environments that are more climatically stable, such as the Isla de Chiloé, these frogs are smaller and greener. The ventral coloration is totally different from the dorsal one, with a pattern of black and white spots which is unique to each individual, just like a human fingerprint.Like the northern species, the call of the Southern Darwin's frog is a whistling. This call is used by males to attract females, but apparently the females also can emit this call, suggesting a social importance that goes beyond its only use for reproductive purposes.The populations of the Southern Darwin's frog have also shown an alarming decline since the 1980's. Particularly worrisome is the situation of the populations near to Concepción, most of which have been extirpated. In addition to the loss of their habitat, we know that these frogs are highly susceptible to a fungal skin disease of amphibians known as chytridiomycosis. For these reasons, this species is classified as Threatened by Argentinian law and Endangered by Chilean law and by the IUCN red list.