By Jeremy Lovell

LONDON, Jan 21 (Reuters) - A giant Chinese salamander that predates Tyrannosaurus rex and the world's smallest frog are among a group of extremely rare amphibians identified by scientists on Monday as being in need of urgent help to survive.

The Olm, a blind salamander that can survive for 10 years without food, and a purple frog that spends most of its life four metres underground are also among the 10 most endangered amphibians drawn up by the Zoological Society of London.

"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," said EDGE head Jonathan Baillie.

EDGE, which stands for Evolutionarily Distinct and Globally Endangered, is a project set up a year ago to identify and start to protect some of nature's most weird and wonderful creatures.

"The EDGE amphibians are amongst the most remarkable and unusual species on the planet and yet an alarming 85 percent of the top 100 are receiving little or no conservation attention," said the project's amphibians chief Helen Meredith.

While last year's launch focused on at risk mammals, this year the focus shifted to neglected amphibians.

"These animals may not be cute and cuddly, but hopefully their weird looks and bizarre behaviours will inspire people to support their conservation," Meredith added.

Not only are the target species unique, the project itself is breaking new ground by using the internet at www.zsl.org/edge to highlight threatened creatures and encourage the public to sponsor conservation.

Global warming and human depredation of habitat are cited as root causes of the problem facing the creatures from the massive to the minute.

The Chinese giant salamander, a distant relative of the newt, can grow up to 1.8 metres in length while the tiny Gardiner's Seychelles frog when full grown is only the size of a drawing pin.

Also on this year's list is the limbless Sagalla caecilian, South African ghost frogs, lungless Mexican salamanders, the Malagasy rainbow frog, Chile's Darwin frog and the Betic midwife toad whose male carries fertilised eggs on its hind legs.

"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," said EDGE's Baillie. (Editing by Jon Boyle)

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