Atelopus or harlequin or stubfoot toads, is a large genus of true toads native to Central and South America, ranging as far north as Costa Rica and as far south as Bolivia. Atelopus species are small, generally brightly colored, and diurnal. Most species are associated with mid- to high-elevation streams. This genus has been greatly affected by amphibian declines, and many species are now considered endangered, while others already are extinct. While threatened by habitat loss, pollution, and introduced species, the primary cause of these declines appears to be the chytrid fungus Batrachochytrium dendrobatidis.