Giant Salamander of China – Wikipedia

Andrias Davidianus

Andrias Davidianus , the Giant Salamander of China , is a kind of urodeling of the cryptobranchidae family ^{[ first ]} . This giant salamander lives in China and was introduced to Taiwan as well as in Japan. It is the largest amphibian living in the world ^{[ 2 ]} .

Researchers have shown in 2018 that there would be in fact at least 5 species in fact (all critical in danger of extinction although in the past common in rivers in southeast China). All seem to come from an ancestral population that began to diverge 5 to 10 million years ago ^{[ 3 ]} .

Holotype du Mnhn ^{[ 4 ]} , of Andrias Davidianus , the giant salamander collected by Father David in Tibet

Gender name Andrias is a word of scientific Latin created in 1837 by the Swiss naturalist Tschudi for the large fossil salamanders of the Miocene. It is derived from the Greek ανδρ- Andr- Anger , “Man”, because the first specimen found was taken for a dead man at the time of the flood ^{[ 5 ]} .

The specific epithet davidii is dedicated to Father David, his discoverer in China.

At the end of 1869, after a very fruitful collection of specimens of plants and animals in Moupine in Eastern Tibet, Father Armand David decided to explore a «Coin Oriental Du Kokonoor (Qinghai)» up to mars 1870 (Report ^{[ 6 ]} ). He will bring back a major discovery: the Chinese giant salamander, Sieboldia davidii . An imposing animal that has the reputation of a voracious predator. The individual he reports is olive -in -color with brown spots and marbles ^{[ 7 ]} .

During his third exploration of October 1872 To April 1874 , he again collects specimens of the giant salamander in the Han valley (汉江 han jiang ). The April 4, 1873 , in Ouang-Kia-Ouan, two hunters sent in exploration, bring him alive five specimens of OA-AO-Yu (Baby fish Wawayu “Baby fish”), called so because they make a little cry, a little glou-slide heard, when touched. Father David notes that the salamanders are of the same species as that collected at Tchong-Poc,

“And an old Christian old man told my young people that he saw one who weighed a little more than forty Chinese books, that is to say, twenty-five kilograms. These men tell me that these amphibians are far from being abundant in the streams of the Western mountains: we only know in a single stream, which they have destroyed, it seems, all fish. Also, these animals leave their clear waters there during the night, to hunt frogs and earthworms; They also eat crabs, and my beasts have disgorged several on the way. At the report of the fishermen, we only see OA-OA-YU in the large river when large thunderstorms have resulted in the top of the streams.
The Chinese do not fish Sielboldia that to have their skin, they sell to pharmacists; They rarely eat the flesh that is white and nauseating, as I have experienced it previously. »»

— Journal ^{[ 8 ]}

These various specimens of the giant Salamander of China were sent to the National Museum of Natural History (MNHN) which still presents their digital photos online ^{[ 9 ]} .

In 1871, following the first sending of Father David, the zoologist of the MNHN, Émile Blanchard gave a description in it in Note on a new gigantic salamander (Sieboldia Davidiana Blanch.) Of Western China ^{[ ten ]} . He compares it to the gigantic Salamander of Japan ( Sieboldia Maxima – Maximum salamandra Schlegel), discovered in 1829 by Franz de Siebold (1796-1866), a Bavarian naturalist who explored Japan and finds that the Salamander of China is distinguished by enough characters to make it a distinct species.

The species will then be transferred under the genus Andrias.

Head of Andrias Davidianus

Skeleton of Andrias Davidianus

Andrias Davidianus In a Shanghai aquarium

Andrias Davidianus measure approximately 100 cm . In the past we have captured and measured individuals measuring up to 1.80 m length and weighing up to 65 kg , but the specimens observed recently are much smaller. Its tail represents approximately 59% of the body size and its extremity is flattened laterally in the shape of a rowing. The giant Salamander of China, with those in Japan and North America, is one of the largest living amphibians in the world. Its average longevity exceeds 30 years, and captive specimens have been able to reach an age approaching 80 years. In 2015, a specimen over 200 years old was found in China ^{[ 11 ]} .

The general shade of the body varies from light brown to dark brown, sometimes close to black, with scattered blackish spots. The body and the head have a rather flattened look. The head is wide, the mouth large with small eyes without eyelids which cannot focus on the same object at the same time, hence a bad vision. To find their prey, animals are therefore dependent on touch and perhaps smell, taste, or even sensitivity to vibrations or electric field. The skin is viscous and has irregular folds on the sides. The legs, well developed, carry four fingers at the front and five in the back.

Breathing is partly ensured by the skin. The latter lets the dioxygen enter and take out carbon dioxide. This added characteristic, to a slow metabolism, allows the giant salamander to stay most of the time at the bottom: it only rises to the surface to breathe from time to time. When their larval gills are reduced, adults develop a clearly visible fold on the skin, along their sides, which increases the absorption surface of oxygen. Its large size, the absence of branchies and reduced lungs confine this species in current water areas.

The giant Salamander of China is essentially active at night. Camouflage and patience are its main assets for hunting. Tapie at the entrance to her lain, dug under the bank of a river, she awaits her prey, in passing by which she projects her head in front of a lively and lateral gesture and grabs them in her mouth. Its favorite prey are crayfish, crabs, small fish, but also worms, insect larvae, anoures (frogs and toads) and their tadpoles, molluscs, reptiles or small swimmers. This giant salamander also hunts smaller salamanders and sometimes folds down on frogs or fish scalp. It can also have cannibal behavior. Although it only has small “larval” teeth, its catch is tenacious and its bite powerful. The method used in the food of this species is known as asymmetrical oral suction, where the lower jaw falls back quickly and near the prey which is sucked in its mouth.

China’s giant salamander reproduction season seems to take place between August and September. His roommate close to vaging earned him the nickname “Nourrisson Poisson” in China. The female deposits near the male a trail of a very large number of eggs, between 500 and 1000, distributed in two long gelatinous cords. If the female does not find a male to fertilize her laying, she devours it. Otherwise, the male hunts the female, buries the laying in a deep burrow (reproduction cavity), then releases her sperm and, waving the water around the eggs, fertilizes them thus. With its enthusiasm members, it makes a cord ball and protects them from predators until hatching, 50-60 days later ^{[ twelfth ]} .

At birth, larvae measure only 30 mm And have external gills that will regress at the time of metamorphosis, when their size has reached around 200-250 mm long. They will only acquire the metabolism of an adult at the age of three. Sexual maturity would be about 15 years old.

The giant salamander lives in rivers, lakes, marshes and expanses of freshwater from China. The species is entirely aquatic and endemic to continental China, but it has probably been introduced to Taiwan ^{[ first ]} ELLE Se Rencontre Au Guangxi, Au Guangdong, AU Fujian, AU Hunan, AU Jiangxi, AU ZHEJIANG, AU JIANGSU, AU Anhui, AU Hubei, AU Guizhou, à Chongqing, AU SI, AU SI chuan, gansu, shaanxi, shanxi, Henan ET AU Hebei ^{[ 13 ]} . Its distribution area is now strongly fragmented.

The giant salamander is present between 100 and 1,500 m altitude, in the bright waters of rivers rich in oxygen. Its habitat consists of rocks, mountain streams and clear and fast water lakes. The species generally finds its optimum in forest areas with moderate altitudes, particularly between 300 and 800 m . She occupies the underwater hollows and the cavities, spending most of her time in the water.

The giant Salamander of China evolves in the three great river ecosystems of China, the river yellow river (yellow river), Yangtze and Zhu Jiang (pearl river). Until the construction of canals, about 1,400 years ago, these rivers had been isolated from each other. There was no displacement of salamanders by humans during these transformations of the three hydrographic networks. Everything suggests that the salamander populations of these three river systems would be genetically distinct to each other. Recent works reveal genetic and geographic differences between the populations of salamanders. According to this hypothesis, A. Davidianus would actually be a composite of several genetically distinct species ^{[ 14 ]} .

Giant Salamanders of China for sale in a restaurant in Hongqiao (虹桥), Wenzhou, Zhejiang (China): the price is 880 CNY/JIN, around 215 euros/kg or $ 280 US/KG, which places them in the segment luxury diet and makes it an attractive target for poaching.

In danger [ modifier | Modifier and code ]

The largest amphibian living in the world has seen its population considerably decline since the 1950s. Between the anthropogenic pressure by degradation of its environment and the food hunt for local populations, the giant salamanders of China have undergone a dramatic decrease in their workforce since years 1960. Poaching even rages in protected areas, because their flesh is used in the composition of delicate dishes of chic tables, the yewei : Capture and illegal trade are encouraged. The species is considered to be both a luxury food and a large source of traditional drugs in China. A factor that makes the Chinese giant salamander particularly vulnerable to hunting, is that it is easy to catch: it is hidden in the crevices of rock from which it is easy to find and detach. It remains a lucrative option for hunters, who can sell her flesh for around 100 $ Us per kg, which remains a very large sum for the majority of Chinese citizens.

The Chinese government has declared the giant Salamander of China, a protected class II species and is listed in the category of species in danger of extinction on “The Chinese Red Book of Amphibians and Reptiles” as well as in the Red List of the IUCN ^{[ 15 ]} .
Water pollution and large -scale development of all country rivers modify and poison its habitat. The habitat of the giant Salamander of China has been destroyed and fragmented by intense agricultural activities, the deforestation and the construction of dams, electrical equipment and tanks. This aggravates the erosion of the soil and causes an increase in runoff and the siltation of watercourses, reducing the quality of the water and preventing the species from obtaining sufficient oxygen through its skin. Strongly decreased by the loss of its primary home, the giant Salamander of China has been under protection of the State since 1973 and in Annex I of the CITES ^{[ 16 ]} . Annex I includes endangered species, and trade in specimens of these species is only authorized in exceptional circumstances. Unfortunately, although the CITES regulates international trade in species, it has no competence on domestic trade within China, which constitutes the primary market.

Conservation [ modifier | Modifier and code ]

An understanding of the genetic diversity of the Chinese giant salamander is essential for the formulation of conservation strategies and policies. One of the main conservation objectives is to preserve existing genetic diversity. Human relocations would have had a substantial influence on the structure of the population. This artificial dispersion would have caused an increase in gene flows between geographically separate populations, and the reduction in local genetic diversity. Conservation policies should try to stop the relocations by man. On the other hand, it may be desirable to establish the breeding programs on-site And from the situation Using individuals of a localized population. It would also be necessary to establish a gathering of reproducers from the non -relocated natural population in order to maintain the original species, which has not undergone genetic modifications during human trips through the regions of China.
A population from the situation is ideally a reproduction colony of a species maintained outside of its natural habitat, giving rise to individuals of this species arranged in the problems linked to their situation in the wild. This can be located in the living environment of the species or in another country with installations that can support a captivity reproduction program of this species.

It would be interesting to study the giant Salamanders of China living in areas close to the Tibetan plateau, where human activities have less influence on populations. Many research has been carried out for the protection and artificial reproduction of Andrias Davidianus across China. An artificial reproduction reserve was built in 1960 in the city of Wudaosui in the Sanzhi region, in Taiwan. Another reserve of the region, with the collaboration of “Hunan Aquatic Science Institution” proceeded in 1978 – 1980, to research on the artificial reproduction of the giant salamanders of China. For the first time in the world, the artificial hatching experience has worked. It was a great advance and a government awareness for the protection of these endemic salamanders.
Since the 1980s, 14 nature reserves have been created in the provinces of China to protect the wild population of giant salamanders. Unfortunately, difficulties in preservation and treatments are sometimes observable in these reservations, often due to a lack of attention and insufficient means.

The study published in 2018 shows that it is currently currently at least 5 species, from an ancestral population which began to diverge 5 to 10 million years ago ^{[ 3 ]} .
To restore wild populations, the Chinese government encourages the liberation into rivers of young individuals from commercial farming farms, but we have just shown by comparing the DNA of 70 wild salamanders to that of 1034 individuals raised to the farm than A single genome is present in farms while in nature the species presents at least five very distinct genetic groups. The breeding salamanders released in the wild are therefore at the origin of genetic pollution ^{[ 3 ]}

Recommendations [ modifier | Modifier and code ]

Three recommendations for the development of the cash management program were proposed by Wang, Zhang, Wang, Ding, Wu and Huang in 2004 ^{[ 17 ]} ::
First of all, expertise should be made, bringing together the geographic and demographic statutes for the conservation of species to obtain a better chronological understanding. The genetic data of populations and survival characteristics are thus included in different environments.

It would also be relevant to organize better protection of the giant salamanders of China, in particular in the nesting areas, accompanied by a prevention of contamination resulting from the evacuations of agricultural pollutants and constructions. A legal strengthening framing the illegal collection and transport of protected animals is essential in this process.

Finally, researchers offer an information campaign on the need to protect this endemic species to local populations and workers. This communication project must integrate the overall management of the species conservation.

In 2018, scientists recommend protecting giant salamander species in their original environment (which must therefore be protected) and not to try to reintroduce individuals from breeding to limit the risks of genetic pollution ^{[ 3 ]} .

• Megalobatrachus sligoi ^{[ 18 ]} was placed in synonymy with Andrias Davidianus par thorn a 1968 ^{[ 19 ]}
• Andrias Scheuchzeri , fossil species, is sometimes considered to be synonymous with Andrias Davidianus , from which it cannot be osteologically distinguished ^{[ 20 ]} .

• Blanchard, 1871 : Note on a new gigantic salamander (Sieboldia Davidiana Blanch.) Of Western China . Weekly reports of the sessions of the Academy of Sciences, vol. seventy three, p. 79-80 ( Full Text ).