Rediscovered: rare species of frogs that were feared extinct

Two rare species of tropical frogs that were thought to have gone extinct have been rediscovered in a remote forest region of South America that was destined to be developed for holiday homes.

Scientists said it was the first time in 14 years that anyone had seen the two endangered animals and the sightings raised hopes that other species of amphibians feared to have succumbed to a fungal infection had survived.

The two frogs - the Santa Marta harlequin frog and the San Lorenzo harlequin frog - were found by biologists working in the El Dorado Nature Reserve on the north-west slope of the Sierra Nevada de Santa Marta massif, on the Caribbean coast of Colombia. The area is one of the highest coastal mountain ranges in the world, rising from the shores of the Caribbean Sea to almost 19,000 feet. It contains an extraordinary number of species which are found nowhere else but was going to be developed as a tourist resort until it was afforded protection earlier this year.

Frogs, toads, newts and salamanders - the amphibians - are as a group suffering a greater rate of extinction than any other class of animals. One reason is a fungal disease, chytridiomycosis, which is thought to have spread rapidly over the past 50 years because of the global trade in African frogs for research.

Neither of the rediscovered frog species was infected with the disease, raising hopes that the species can be saved in the newly protected area, according to Conservation International, a non-profit organisation based in Washington DC.

The fungus has been found as close as 25 miles away on the other side of the Sierra Madre mountains, and scientists studying the frogs hope to learn how they have avoided the infection.

"It's a race against time to prevent chytridiomycosis from wiping out amphibian populations, but now we have discovered what appears to be healthy populations of these endangered species," said Claude Gascon of Conservation International. "Creating the El Dorado Nature Reserve has given Colombia and the world a unique jewel that will prevent the extinction of threatened species of birds and frogs found nowhere else on the planet."

Amphibians live on land but need water to breed and it is thought that this dual requirement may make them especially vulnerable to climate change and loss of suitable breeding habitats. In recent years, however, scientists have noted that the spread of the fungal disease has put added strain on many species of amphibians and so discovering any wild populations that appear to have developed an immunity may help other species at risk.

Researchers at Colombia's Magdalena University and El Dorado Nature Reserve found the two rediscovered frog species on a research trip funded by the Darwin Initiative and the National Environmental Action Fund.

El Dorado is the sole breeding ground of the endangered Santa Marta parakeet and is home to five threatened amphibians which are found nowhere else in the world.