Up to 21 new species of animals and plants have been discovered in a remote region of Vietnam. Scientists have confirmed that they have identified eleven previously unrecorded species, and that ten more are still being examined.

The finds include a frog-eating snake, two butterflies, orchids that grow like fungi and an aspidistra with a flower that is almost black.

The area of central Vietnam where the finds were made is known as the Green Corridor; several mammals were discovered there in the 1990s.

Zoologists involved in the expeditions to the Annamite mountain range said that the area was so rich in wildlife that the recent discoveries may represent a small sample of the unknown species living there.

“You discover so many new species only in very special places, and the Green Corridor is one of them,” said Chris Dickinson, of the WWF, which led the expeditions. “Several large mammal species were discovered in the 1990s in the same forests, which means that these latest discoveries could be just the tip of the iceberg.”

A significant number of threatened creatures and plants was also identified during the survey, which was carried out in 2005 and 2006.

Among these were fifteen reptiles and amphibians, six bird species and the highest known concentration of the white-cheeked crested gibbon, which is one of the most endangered primates in the world.

The Green Corridor includes extensive tracts of wet evergreen forests and ecologically valuable areas of lowland river. It is thought to be the home of the saola, a forest-dwelling ox discovered in 1992.

The new snake has been named the white-lipped keelback, Amphiesma leucomystax, because of the broad stripe on its upper lip giving the appearance of having a white moustache. It can grow to more than 2½ft (80cm) long.

Two butterflies were identified, including one for which a genus had to be created, to add to the six that have been discovered in the region since 1996. Scientists said that the discovery of the new genus was of particular significance because it was an indicator of the unique ecological properties of the forests.

Of the five confirmed orchids, three were unusual in being leafless. They do not have chlorophyll and do not photosynthesise and have survived by feeding on nutrients provided by decaying material, just as many fungal species do.

An aspidistra, Aspidistra nicolai, had a dark blue flower that was almost black, and other new plant species include a type of arum, Cryptocoryne vietnamica, with yellow flowers surrounded by funnel-shaped leaves.

The second aspidistra, which has delicate yellow flowers, has yet to be named. The discovery comes after the identification in 2005 of six species of aspidistra that were collected on an expedition in 1996 and grown at the Munich botanical gardens until they could be officially described by scientists.

Environmental organisations are concerned about the future of wildlife in the region because of threats from activities such as hunting, illegal logging and development.

Dr Dickinson said: “The central Annamite mountains of Vietnam and Laos are unique and amazing forests. They are very wet forest areas with little or no dry season, with no month receiving less than 40mm of rain.

“Such forests are naturally quite localised and appear to have acted as Ice Age refugia - old forests that have been climatically stable for millennia. Due to previous isolation and a stable climate, these forest areas have evolved a suite of species restricted to these very wet forests.

“One problem is that the sale of wild orchids to local Vietnamese is quite common, with many extracted from valuable forests areas. How many new species of orchid are being sold in the markets of Hue to Vietnamese tourists and locals we have no idea of knowing.”

Authorities in Thua Thien Hue province have pledged to conserve and manage the forest’s sustainably.

Hoang Ngoc Khanh, director of the Thua Thien Hue provincial forest protection department, said: “The area is extremely important for conservation and the province wants to protect the forests and their environmental services, as well as contribute to sustainable development.”

— A frog thought to have been extinct for almost 20 years has been found in a South American forest.

The brown and metallic-green tree frog, Isthomhyla rivularis, was thought to have been one of several amphibians killed off by a combination of a fungal virus and the effects of climate change.

The rediscovery raises hopes that the creature reputed to be the first victim of climate change, the golden toad, Bufo pere-glenes, may yet be found again.

Andrew Gray, the curator of herpetology at the Manchester Museum, part of the University of Manchester, came across the frog at the Monteverde Cloud forest reserve in Costa Rica. He scaled a tree during the night as he tried to identify a male frog calling from a bough. “One look at the specimen in my hand and I knew I had caught something very special,” he said.

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