Atelopus

Atelopus is a large genus of small, brightly coloured, diurnal toads commonly called harlequin frogs, native to montane stream habitats from Costa Rica south to Bolivia. The genus has been catastrophically affected by global amphibian declines, driven primarily by the chytrid fungus Batrachochytrium dendrobatidis alongside habitat loss and pollution; roughly forty percent of its described species are considered possibly extinct, a figure that rises further once data-deficient species are included. Despite this, some species once feared lost have been rediscovered decades after their last sighting, including Atelopus ignescens and A. varius, and captive-assurance colonies have been established for several critically endangered members. New Atelopus species continue to be described regularly, reflecting both the genus's remaining diversity and the urgency of its conservation crisis.