Feb 24

A male Rabb’s fringe-limbed treefrog, believed to be one of only two of its species left in the world, has died, bringing the population of this Critically Endangered amphibian down to a single remaining individual.

Photo of a captive Rabb's fringe-limbed treefrog

The male had been kept at Zoo Atlanta in the United States, as part of a last-ditch effort to save the species from extinction. However, following a decline in its health and behaviour the zoo took the difficult decision to euthanize the frog, both to prevent it suffering and also to ensure that invaluable genetic material could be preserved. This material may one day allow scientists to study the species further.

Amphibians decompose much more rapidly than do many other classes of animals. Had the frog passed away overnight when no staff members were present, we would have lost any opportunity to preserve precious genetic material,” said Joseph Mendelson, Curator of Herpetology at Zoo Atlanta.

To lose that chance would have made this extinction an even greater tragedy in terms of conservation, education and biology.”

Photo of Rabb's fringe-limbed treefrog clinging to branch

On the brink of extinction

Rabb’s fringe-limbed treefrog was first discovered by Mendelson and his colleagues during a 2005 field expedition to Panama, and was only officially described as a new species as recently as 2008.

A large frog with substantial webbing on its feet and scalloped fringes of skin along its forearms and feet, this unusual amphibian has been known to leap from treetops and use its outstretched limbs and large, webbed hands and feet to glide to the ground.

Sadly, the arrival of the fungal disease chytridiomycosis, which has begun to threaten native amphibian populations in Panama, has decimated this rare frog. Rabb’s fringe-limbed treefrog has not been seen in the wild since 2007, and is now believed to exist only in captivity.

Even if some wild individuals have survived the fungal disease, the habitat of this species is also under serious threat from forest clearance, and its restriction to one small area puts the species at particularly high risk of extinction.

Photo of Rabb's fringe-limbed treefrog

Last lonely frog

The only other Rabb’s fringe-limbed treefrog known to exist is another male, kept at the Atlanta Botanical Garden. With the loss of the male at Zoo Atlanta, this remaining individual is likely to be the very last of his species.

According to Dwight Lawson, Deputy Director at Zoo Atlanta, “This is the second time in my career that I have literally seen one of the very last of its kind die and an entire species disappear forever with it. It is a disturbing experience, and we are all poorer for it.”

The ongoing amphibian extinction crisis has taken a rich diversity of animals from us, and more effort and resources are desperately needed to halt the losses.”

Photo of Rabb's fringe-limbed treefrog, close-up of head

Global conservation effort

Amphibian populations are declining around the world, and Rabb’s fringe-limbed treefrog is not the only species to be facing extinction. Nor is it the only amphibian thought to now exist only in captivity.

Over a third of all amphibian species are currently threatened with extinction, with many facing a range of threats, including habitat loss, pollution, and the rapid spread of the deadly chytrid fungus.

Fortunately, many zoos and other organisations are working together to address this extinction crisis and to save threatened amphibian species. Although it may already be too late for Rabb’s fringe-limbed treefrog, there may still be time to bring other endangered species back from the brink of extinction.

Read more on this story in the Zoo Atlanta press release.

Find out more about amphibian conservation at Amphibian Ark.

View photos of Rabb’s fringe-limbed treefrog on ARKive.

View photos and videos of other threatened amphibians on ARKive.

Liz Shaw, ARKive Species Text Author