Earless Frogs in the Andes

Throughout South America, there are nearly 700 species of land-breeding or terrestrial-breeding frogs (family Strabomantidae). They are the most diverse group of amphibians living in the Tropical Andes. Terrestrial-breeding frogs use a specialized reproductive mode called direct development in which embryos hatch directly into froglets (i.e., there are no free-living tadpoles)—a strategy that allows the group to exploit a wide variety of habitats, provided those habitats contain sufficient moisture. While many species of these direct-developing frogs resemble one another and have similar life histories, several subgroups are distinguished by the evolutionary loss of hearing structures. Many frogs that lack hearing structures do not vocalize or respond to advertisement calls during reproduction. How these frogs communicate and what factors drove the loss of hearing structures in this diverse group remains unknown.