The world’s tiniest frog and a salamander that can go ten years between meals have been identified as being among the rarest and most remarkable amphibians.

The “weird and bizarre” animals are on a list of the 100 most biologically valuable of all amphibians struggling for survival. Scientists at the Zoological Society of London compiled the list for the launch of the Evolutionarily Distinct and Globally Endangered (Edge) project for amphibians.

The top 100 were narrowed down to a list of ten species that scientists regarded as being in the most desperate need of help. All of them are endangered but, rather than classify them simply on the basis of the threat of extinction, their value as representatives of distinct evolutionary lineages has been taken into account.

“These animals may not be cute and cuddly, but hopefully their weird looks and bizarre behaviours will inspire people to support their conservation,” said Helen Meredith, who is coordinating the project. “The Edge amphibians are among the most remarkable and unusual species on the planet, and yet an alarming 85 per cent of the top 100 are receiving little or no conservation attention and will become extinct if action is not taken.”

Ten species were selected for priority action and more would have been selected had funds and facilities been available. Other species were regarded as more rare and valuable but were already receiving help from conservationists. Among those selected for immediate assistance was the Chinese giant salamander, Andrias davidianus, the largest amphibian and one of the last survivors of a lineage that evolved 170 million years ago.

Others include the Seychelles frogs, Sooglossus gardineri, which grow to just 8-11mm and, as the smallest frogs in the world, could sit on the head of a drawing pin, and Malagasy rainbow frogs, Scaphiophryne gottlebei, which climb vertical rock faces to escape floods.

The purple frog, Nasikabatrachus sahyadrensis, which was discovered only in 2003, is among the oddest to be selected. It spends 50 weeks of the year buried in loose soil chasing termites. Another, the Olm, Proteus anguinus, is a semi-transparent blind salamander that can live for more than a decade without food.

The Edge project addressed mammals last year and has now been extended to the 6,200 amphibian species that are among the most threatened wildlife in the world. Amphibians are under increasing pressure in the wild because of a series of threats to their survival, particularly the rapid spread of the chytrid fungal disease that could drive an estimated 500 species into extinction and has already been blamed for the loss of some. Other threats include climate change and habitat loss.

Jonathan Baillie, head of the Edge project, said: “These species are the canaries in the coalmine. They are 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.”

On the Edge: ten species in desperate need of help

1 Chinese giant salamander
2 Sagalla caecilian
3 Purple frog
4 Hewitt’s and Table Mountain ghost frogs, of South Africa
5 Olm salamander
6 Lungless salamanders, of Mexico
7 Malagasy rainbow frog
8 Chile Darwin’s frog
9 Betic midwife toad
10 Seychelles frogs

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