May 19

One in three amphibian species are yet to be discovered and the remote tropical forests where most are likely to occur need greater protection, according to a new study.

Photo of beaked toad, Rhinella sp. nov.

Nicknamed the “Mr Burns toad” due to its resemblance to the Simpsons character, this beaked toad was only discovered in Colombia last year.

Thousands of species yet to be described

Published in the journal Proceedings of the Royal Society B, the study estimated that, despite centuries of research, around 3,050 amphibian species have yet to be described. Compared to the 6,296 amphibians that are currently known, this means that a third of all species are as yet undiscovered.

The study also looked at mammals, and concluded that around 160 species were yet to be found – about 3% of the current known total of 5,398. The estimates for both groups of species were calculated using a number of factors, including past rates of species discoveries and the extent of unexplored habitats.

Photo of Caquetá titi monkey; defence posture

The Caquetá titi monkey is one of the newest primates known to science, having been discovered as recently as 2008.

There are likely to be more undiscovered amphibians than mammals because amphibians are often more difficult to spot.

Tropical forests likely to harbour most species

The study also said that most undiscovered species are likely to be found in the world’s remote tropical forests, particularly in areas such as the Amazon, Congo Basin and Papua New Guinea. As well as being less disturbed by humans, these habitats are also some of the least explored.

Photo of captive Rabb's fringe-limbed treefrog

Rabb’s fringe-limbed treefrog was first described in 2008, but may already be extinct in the wild due to a fungal disease.

There have been many new species discoveries in recent years, but in general these species tend to be rare and are restricted to tiny ranges. They also face a range of threats, including forest clearance, pollution, climate change, introduced species and, in the case of amphibians, a deadly fungal disease.

According to the authors of the study, “Many of the undescribed species in these two groups are probably in danger of extinction and could well disappear before they are discovered, especially given the high rates of habitat conversion in tropical forests.”

Photo of Sagalla caecilian on leaf litter

Belonging to a highly unusual group of amphibians, the Sagalla caecilian was first described in 2005. It occurs only on a small area of Sagalla Hill, Kenya.

Urgent habitat protection needed

Conservation policies are now urgently needed to protect tropical forests, few of which are currently set aside in formal protected areas. Without conservation action, many species could be lost before they are even known.

The study concluded, “Today’s “hidden” biodiversity need not vanish without a trace. It is up to us to try to prevent such a tragedy.”

Read more about recent species discoveries at Conservation International.

See Amphibian Ark for more on amphibian conservation.

View photos and videos of amphibians on ARKive.

Liz Shaw, ARKive Species Text Author