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Inviato da Wes von Papinešu on Dicembre 10, 1999 at 16:03:51:
CHINA DAILY (Beijing) 09 December 99 Amphibian's hidden life (Liu Jun)
A mysterious salamander which "disappeared" for more than a century has been re-discovered.
But now the elusive creature, considered by scientists to be a "living fossil" is under threat of extinction because of receding wetlands and human interference.
The Xinjiang salamander (Ranodon sibiricus Kessler) belongs to the family hynobius, order urodela, class amphibia and phylum vertebrata.
Russian zoologist Kessler first discovered and named it in 1866. No one saw it for the next 123 years. Wang Xiuling, a professor of the Xinjiang Normal University, is one of the few people in the world lucky enough to have seen this mysterious creature. Even fewer have had the chance to study it.
In June 1989, a local herdsman chanced upon some strange "four- footed fish" in a stream at the foot of the Alataw Mountains about 600 kilometres northwest of Urumqi, capital of Xinjiang Uygur Autonomous Region. A student of Wang heard about them and took one to her.
"I was so amazed when I found out this was the Xinjiang salamander," recalled Wang, 59. With no hesitation, she set out the next day.
But the journey wasn't easy. On the way, Wang fell into the river and almost drowned. Then they met a pack of wolves while resting with a herdsman's family.
Five days later, the local herdsman led them to a brook 2,750 metres above sea level. Similar brooks run out of the ice-capped mountains and converged in the inland Botala River.
Wang was overjoyed to discover more than 600 salamanders in the small brook. She later found 8,000 more in the nearby western Tianshan Mountains.
This fruitful trip enabled her in 1990 to write the first Chinese thesis on the Xinjiang salamander.
She found that Xinjiang salamanders liked to hide under rocks or in the humid sand during the day. At night, they crawled onto the bank and wandered up to four metres away for food, mostly moths, beetles and small insects.
They were most active from midnight to three o'clock in the morning.
The two months from mid-May to mid-July is the time of reproduction for the Xinjiang salamander. Fertilized egg capsules are laid under rocks. The new-born salamander has a pair of exterior gills, which disappear when it matures and begins to breathe through its lungs and skin.
In winter, snow up to half a metre deep shields the grassland. The salamanders hibernate under rocks for six months until warmer weather comes.
In 1991, Wang built a rearing centre at the Wenquan County, 50 kilometres from the salamander's natural habitat.
From an initial 10 pairs of mature and three young salamanders, she bred 73 in April 1992. The next year, she released more than 200 into a valley close to the salamanders' original habitat.
She then started to rear them indoors at the Biology Department of her university back in Urumqi.
But the 22 pairs of wild creatures seemed unhappy in the noisy city. For two years, they did not lay a single egg.
In June 1994, her efforts were rewarded when the salamanders laid seven eggs.
"The hardest thing was to keep the temperature low just like their home," said Wang. With no money for an air-conditioner, she put ice cubes into the water to keep it around six degrees centigrade.
Just days after the salamanders hatched, the daily supply of ice cubes was cut because the factory where she bought the ice shut down production to celebrate a local festival.
"The temperature rose sharply. Despite our efforts, only two survived," she said sadly.
"We worked for five years to get 43 larvae of the Xinjiang salamander in 1994. Only two were left after the accident," she said.
Wang had no more funds to continue rearing the salamanders who were used to the small lab.
Her efforts to preserve the salamanders' natural habitat also proved to be an arduous mission.
The Xinjiang salamander lives within a 500-square-kilometre area centred on the cross point of the 80 degrees east longitude and 45 degrees north latitude.
In recent years, dryer weather has forced the wetlands to shrink. Strong winds, hail storms and floods have killed the salamanders and their food. Wang have even seen adult salamanders eat their new- borns.
But the biggest threat comes from humans. In 1994, hundreds of salamanders in her outdoor rearing centre were washed away when the local government built a park on the site.
One of the valleys where salamanders live is now a tourist spot. With no protection measures, visitors are free to catch the slow and defenceless creatures.
In 1996, Wang was alarmed to find fewer than 2,100 salamanders in the two valleys where she had found 8,600 in 1989.
She tried her best to call attention to the situation. After a meeting with Xie Zhenhua, director of the State Environmental Protection Administration (SEPA), Wang was given 100,000 yuan (US$12,000) from the SEPA and another 100,000 yuan from the Xinjiang local government.
But so far, she has no other resources to create the nature reserve authorized by the Xinjiang local government in late 1997.
Except for five rounds of barbed wire in the heart of the reserve and one guard, the reserve is helpless in the face of grazing cattle and tourists curious about the taste of this old animal.
Although experts agreed two years ago to include the Xinjiang salamander in the Level One State protection list, just like the giant panda, the new list will not be announced until next year. This means that the nature reserve of the salamander still cannot get State funding.
This January, Wang revealed an even more interesting aspect of the Xinjiang salamander in her joint thesis with Professor Qu Lianghu and other researchers at the Bio-Technology Research Centre of the Zhongshan University of Guangdong Province.
Their study showed that the 18S rDNA of the Xinjiang salamander has 97 per cent similarity to that of the coelacanth (Latimeria chalumae).
First discovered in 1938 in the Indian Ocean near southern Africa, the coelacanth is a light blue lobe-finned bony fish. It is the only survivor of the suborder Coelacanthida, order Crossopterygii. Members of related but extinct suborder Rhipidistia are considered to be ancestors of land vertebrates.
In the early Devonian epoch 408-387 million years ago, salamanders and other amphibians evolved from the fishes of the order Crossopterygii. These fishes had lungs, muscular fins supported by bones. They probably propelled themselves out of the drying water. By adding insects and others to their diet, they became less dependent on water.
The closeness of the Xinjiang salamander to the coelacanth means that it might have been the most primitive member of the amphibian family, Wang said.
But further study is needed to determine this assumption. Comparing the DNA of Xinjiang salamanders and amphibians of other orders might lead to even more important discoveries, said Zhang Zhongguang from the Centre of Animal Evolution and Systematics at the Animal Research Institute of the Chinese Academy of Sciences.
"Every species takes up a vital place in our studies. That's why we are so upset about the quick disappearance of species," he said .
Another valuable point of the thesis is that the length of the Xinjiang salamander's DNA ITS (internal transcribed spacer) is 1,900 base pairs. This is 700 more than the average length of other amphibians' ITS.
Although the researchers are not sure of the reason for this difference, they note that the Xinjiang salamander contains valuable information, Qu said.
"The Xinjiang salamander is a real 'living fossil' and a national treasure," he said.
In addition, Wang has found a special structure at the skull of the Xinjiang salamander. With more funding to carry on her study, Wang said she might prove it be a unique species in a unique genus.
"If we don't hurry up, the last 3,000 Xinjiang salamanders may disappear within our generation after living on the planet for 250 million years," Wang said.