Chiriqui Harlequin Frog (Atelopus chiriquiensis)

The Chiriqui harlequin frog, also called Lewis stubfoot toad, was a species of true toad in the family Bufonidae that lived along stream margins in lower montane wet forest and rainforest of the Cordillera de Talamanca, spanning Costa Rica and the Chiriqui and Bocas del Toro provinces of western Panama, at elevations of 1,400 to 2,500 meters. It was a moderately sized toad with highly variable coloring between the sexes, males measuring 28 to 34 millimeters and females 36 to 49 millimeters, and its weakly developed poison glands produced the toxins tetrodotoxin and chiriquitoxin. The species had not been seen in Costa Rica since 1996 or in Panama since the late 1990s, its disappearance driven by chytridiomycosis, habitat loss, and introduced trout, and the IUCN 2019 assessment formally classified it as extinct.