Costa Rican Variable Harlequin Toad, Atelopus Varius

The Costa Rican Variable Harlequin Toad, Atelopus varius, known also as the clown frog, is a neo-tropical true toad belonging to the family Bufonidae. Ranging once from Costa Rica to Panama, A. varius is currently listed as critically endangered and has been decreased to a single remnant population near Quepos, Costa Rica and is assumed to be extinct within Panama. Some recent variation in the air temperature, precipitation, stream flow patterns, and the following spread of a pathogenic chytrid fungus linked to global climate change have been the primary cause of decline for A. varius. A. zeteki has been considered a subspecies of A. varius, but is now usually considered a separate species.

The historic range of A. varius extended from the Pacific and Atlantic slopes of the Cordilleras de Tilaran mountain range in Costa Rica into western Panama. A suitable habitat includes both the pre-montane and the lower-montane zones as well as some lowland sites along rocky streams in hilly areas. Currently, A. varius is limited to a single lowland site along a stream and a small tributary on the Pacific coastal range near Quepos, Costa Rica.

This species is a diurnal frog frequently found on rocks or in crevices along streams in humid lowland and montane forests. It’s mainly a terrestrial species, only going into the water during breeding season, depending on the spray from streams for moisture.

This frog is slow-moving and quite frequently stays in the same area for long periods of time. The obvious or aposematic coloration of this frog probably serves as a warning to the potential predators of the toxicity of the frog’s integument which contains tetrodotoxin, a potent neurotoxin. Its primary food source is small arthropods that are plentiful during the dry season. The only known predator regarding A. varius is a parasitic sarcophagid fly which drops its larvae onto the surface of the frog’s thigh. The larvae then go on to burrow inside the frog and it eat from within. Additionally, large land crabs have recently been seen attempting to prey on A. varius but it’s not clear what, if any, effect this has on the population.

Image Caption: Variable harlequin frog. Credit: Brian.gratwicke/Wikipedia (CC BY-SA 3.0)