Critically Endangered
Atelopus varius
Atelopus varius
Atelopus varius, the Costa Rican variable harlequin toad or clown frog, is a small Neotropical true toad from the family Bufonidae.
Appearance
Recent variation in air temperature, precipitation, stream flow patterns, and the subsequent spread of a pathogenic chytrid fungus (Batrachochytrium dendrobatidis) linked to global climate change have been the leading cause of decline for A. Varius.
Range and habitat
The historic range of A. Varius stretched from the Pacific and Atlantic slopes of the Cordilleras de Tilaran mountain range in Costa Rica into western Panama. Suitable habitat includes both pre-montane and lower-montane zones as well as some lowland sites along rocky streams in hilly areas (ranging from 6 to 2,000 metres or 20 to 6,562 feet in elevation). A. Varius is a diurnal frog often found on rocks or in crevices along streams in humid lowland and montane forests.
Pins are Wikidata “endemic to” fields. Orange dots, when present, are GBIF occurrence tiles — survey bias included.
Breeding
Calling males and egg sites define most frog field work. A species known from one ridge is as narrow as it sounds.
Eggs and damp skin make amphibians quick to vanish from a drained wetland or a forest stripped of litter.
In crisis
Once ranging from Costa Rica to Panama, A. Varius is now listed as critically endangered and has been reduced to a single remnant population near Quepos, Costa Rica (rediscovered in 2003), and has only relict populations in western Panama. The first incidence of its disappearance was recorded after a census conducted between 1990 and 1992 near Monteverde, Costa Rica revealed zero individuals where its population had previously peaked at 751 adults. By 1996, A. Varius was believed to be extinct throughout Costa Rica, even so, in a 2019 assessment, two subpopulations were discovered in the country.
In Panama, mass mortality has drastically reduced populations of A. Varius in recent years and it was believed to be locally extinct, however the species was recorded again in the 2019 assessment. This pathogen can be transmitted between individuals through shed skin cells and is known to infect keratinized body surfaces where it can impair cutaneous respiration and osmoregulation thus resulting in mortality.
Chytrid fungus, collection, and wet-forest loss are the usual pressures on frogs with a high threat category.
Atelopus varius is Critically Endangered on this catalog because that is the IUCN category stored on Wikidata. Confirm the official criteria and any later count on iucnredlist.org.
Sources
Written for this catalog from the English Wikipedia article on Atelopus varius, Wikidata item Q310885. Family and order context is original field-guide writing about the group, not a copied assessment of this one species. Wikipedia text is CC BY-SA. Not an IUCN assessment. Counts, when quoted, can change — confirm them on the recovery programme and on iucnredlist.org.
