EDGE Amphibians: World's Weirdest Creatures Just Got Weirder

ZSL EDGE programme is highlighting some of the world’s most extraordinary creatures currently threatened with extinction. This year ZSL scientists have assessed all amphibian species according to how Evolutionarily Distinct and Globally Endangered (EDGE) they are.

“The EDGE amphibians are amongst the most remarkable and unusual species on the planet and yet an alarming 85% of the top 100 are receiving little or no conservation attention and will become extinct if action is not taken now.” Helen Meredith, EDGE Amphibians coordinator, commented. “These animals may not be cute and cuddly, but hopefully their weird looks and bizarre behaviours will inspire people to support their conservation.”

ZSL has identified and is starting work to protect ten of the most unusual and threatened EDGE amphibian species this year, including:

1. Chinese giant salamander (salamander that can grow up to 1.8m in length and evolved independently from all other amphibians over one hundred million years before Tyrannosaurus rex)
2. Sagalla caecilian (limbless amphibian with sensory tentacles on the sides of its head)
3. Purple frog (purple-pigmented frog that was only discovered in 2003 because it spends most of the year buried up to 4m underground)
4. Ghost frogs of South Africa (one species is found only in the traditional human burial grounds of Skeleton Gorge in Table Mountain, South Africa)
5. Olm (blind salamander with transparent skin that lives underground, hunts for its prey by smell and electrosensitivity and can survive without food for 10 years)
6. Lungless salamanders of Mexico (highly endangered salamanders that do not have lungs but instead breathe through their skin and mouth lining)
7. Malagasy rainbow frog (highly-decorated frog that inflates itself when under threat and can climb vertical rock surfaces)
8. Chile Darwin’s frog (a frog where fathers protect the young in their mouths, this species has not been officially seen since around 1980 and may now be extinct)
9. Betic midwife toad (toads that evolved from all others over 150million years ago – the males carry the fertilised eggs wrapped around their hind legs)

Dr Jonathan Baillie, Head of the EDGE programme, commented, “Tragically, amphibians tend to be the overlooked members of the animal kingdom, even though one in every three amphibian species is currently threatened with extinction, a far higher proportion than that of bird or mammal species. These species are the “canaries in the coalmine” – they are highly sensitive to factors such as climate change and pollution, which lead to extinction, and are a stark warning of things to come. If we lose them, other species will inevitably follow. The EDGE programme strives to protect the world’s forgotten species and ensure that the weirdest species survive the current extinction crisis and astound future generations with their extraordinary uniqueness.”

EDGE (Evolutionarily Distinct and Globally Endangered) animals are those with few close relatives and are highly distinct genetically. These animals are also extremely endangered and desperately in need of immediate action to save them from becoming extinct. By mathematically combining a measure of each species’ unique evolutionary history with its threat of extinction, the scientists are able to give species an EDGE value and rank them accordingly. In January 2007, the EDGE team assessed all mammal species and released the list of the top 100 EDGE mammal species. The scientists have now done the same for all amphibian species (frogs, salamanders and caecilians) and have found that 85 of the top 100 are receiving little or no conservation attention.

Amphibians are declining as a result of a range threats including habitat destruction, pollution, climate change and disease. Scientists at the Zoological Society of London (ZSL) are currently researching the diseases affecting amphibians, with particular focus on the chytrid fungus, which is implicated in mass mortality events globally.