'Extinct' toad rediscovered after 30 years

Atelopus Mindoensis—more commonly known as Mindo harlequin toad—was long believed to have been extinct due to chytrid. But this rediscovery would mean that there still is a chance for amphibians despite the disease.

'Extinct' toad rediscovered after 30 years
Photo by Melissa Costales

Over the past 30 years, a fungal disease called chytrid wiped out a significant amount of amphibian populations worldwide. This disease causes the animals’ skin to lose the ability to absorb oxygen and water. The Atelopus genus was affected by this disease harder than the others.

In August 2019, a conservation biologist at University of New Brunswick, Melissa Costales, had travelled to the cloudforests of northern Ecuador with her colleagues in search for rainfrogs. After a long day and encounter of nearly a dozen rainfrogs, one scientist noticed a bright fleck of green on a low-hanging leaf and “There it was,” says Costales, “the legendary Atelopus mindoensis!”

Atelopus Mindoensis—more commonly known as Mindo harlequin toad—was long believed to have been extinct due to chytrid. But this rediscovery would mean that there still is a chance for amphibians despite the disease.

Costales says that the Mindo harlequin toad’s reappearance could be a sign that they have already become resistant to chytrid. It is yet to be confirmed, however, this amphibian isn’t the first to have developed a resistance to chytrid. Mindo harlequin toad isn’t the first one to reappear after being suspected of extinction either. In fact, it makes it the ninth species in the Atelopus genus since 2003.

Like a lot of other diseases, including the global pandemic we are experiencing today, chrytid is a disease that is expected to subside. “There’s an outbreak stage, but then frequently, there's a drop-off in terms of the severity of disease within a population. And so we have experienced a similar thing with amphibians.” Says Jamie Voyles, a disease ecologist at the University of Nevada in Reno.

Costales and her colleagues returned to the same reserve after their discovery in August and found 5 more toads which they refuse to name for the meantime. Through chytrid is still present in the area, two of the captured toads tested negative—this could mean that they never came into contact with the fungi or may also be that these amphibians have evolved in a way that could resist the disease.