AmphibiaChina 中国两栖类.

Description
Heavily built salamander. Head strongly depressed, snout obtusely truncate; nostrils small, rounded, close to the edge of the upper lip and at the corners of the truncated snout, the internasal space less than half of the interorbital space. Eyes small, rounded, dorso-lateral in position, and without eyelid. Top of head more or less flat, with a rounded temporal protuberance above and behind each eye. Vomerine teeth in an arched series starting between the choanae, parallel to the maxillary and premaxillary series. A thin lower labial fold starting about midway between nostril and eye to the angle of the mouth. Trunk less depressed than head, with about fifteen costal grooves, a strong vertebral groove, and strong lateral dermal folds. Legs short and flattened. Tail 59% of the body length, compressed. Dorsal tail fin extending to the trunk. Skin rough and porous, with wrinkles, folds and tubercles. Color of animals is dark brown, black or greenish. Irregularly blotched and marbled with dusky spots. Total length about 100 cm, Chang (1936) quotes a maximum of 180 cm, but most animals found nowadays are considerably smaller (Liu and Liu 1998). Specimens of 115 cm weigh approx. 25 pounds (Liu 1950). Closely related and very similar to A. japonicus. There are no records of geographic variation.

The two species of Andrias - A. davidianus occurring in China and A. japonicus in Japan - are the largest living salamanders, with adults reaching a total length of more than 100 cm. The two species are similar with several features in common. Vomerine teeth located on anterior margin of vomer, parallel with maxillary tooth row; teeth form a long arc. Nasals in contact with maxilla; frontal does not enter external naris. Pterygoid broad, almost in contact with base of maxilla. Hyoid arches cartilaginous. Two pairs of branchial arches. Body large, no spiracle on head; distance between nostrils less than half the distance between the eyes. Tongue large. Tubercles on highly vascular skin. Permanently aquatic.

The Chinese Giant Salamander is very similar to the Japanese Giant Salamander and differs from the latter by the arrangement of tubercles on the head and throat. The tubercles of A. davidianus are mostly in pairs, and much smaller and fewer than those of A. japonicus. The tubercles on the throat are characteristic for each species. In A. davidianus, the very small paired tubercles are arranged in rows parallel with the lower jaw. In A. japonicus they are mostly single and large and irregularly scattered. The snout is less rounded and the tail a little longer in the Chinese species. The colour is darker with large black patches (Chang 1936; Liu 1950; Thorn 1969).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: China. Introduced: Taiwan.

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (4 records).

The mountain streams of China, from Qinghai to Jiangsu and south to Sichuan, Guanxi and Guangdong. Middle and lower tributaries of the Yangtze river, Huang He (Yellow river) and Zhu Jiang (Pearl river) (Liu and Liu 1998). Finds in Taiwan may be the result of introductions.

The habitat consists of rocky mountain streams and lakes with clear, running water, at moderate altitudes (below 1500 m, especially between 300 and 800 m), where the animals occupy hollows and cavities under water. The salamanders spend their whole lives in water.

Life History, Abundance, Activity, and Special Behaviors
The female lays approximately 500 eggs in a string in an underwater cavity, occupied by a male. The eggs measure on average 22 mm by 19.2 mm; the diameter of the embryo is 8-9 mm. Eggs are fertilized externally and are guarded by the male, until they hatch after 50-60 days at a length of 30 mm.

Mating behavior has been described for A. japonicus (Kawamichi and Ueda 1998) and probably is similar for A. davidianus. In the reproductive season, which appears to fall in August-September, the male occupies a breeding cavity, which he aggressively guards against intruders. Females enter the cavity and leave it directly after spawning. The male fertilizes the eggs and guards them until they hatch after about 50-60 days.

Larva
After 30 days post-hatching, the larvae start eating; reduction of gills begins when the larvae are 200-250 mm total length (Haker 1997). The larvae of the Chinese Giant Salamander have longer gills than those of A. japonicus, fingers and toes are more pointed, and the colour is darker. The larva resembles the adult in shape.

Trends and Threats
Not only have populations become smaller and fragmented, the individuals captured are smaller than they used to be, most probably as a result of over-collecting (Liu and Liu 1998). There are no data on abundance in English.

Relation to Humans
The Giant Salamander is considered to be a delicacy and collected for culinary and commercial purposes. Captive breeding has proved to be possible. Breeding farms were established in Hunan, Shaanxi, Jiangxi and other provinces since the early 1970s (Liu and Liu 1998) but there are insufficient data about the results. It is doubtful if commercial farming will be able to alleviate the pressure on natural populations. Breeding has been achieved in Europe (Haker 1997). The European experience and the Japanese results with Andrias japonicus could help Chinese farms to improve their results.

Possible reasons for amphibian decline

General habitat alteration and loss
Dams changing river flow and/or covering habitat
Local pesticides, fertilizers, and pollutants
Loss of genetic diversity from small population phenomena
Intentional mortality (over-harvesting, pet trade or collecting)

Comments
There is a vast body of literature, much of it in Chinese (cf. Ye et al. 1993 and references therein). For this species the name Andrias scheuchzeri (Holl 1831) has been resurrected (Frost, 1999, Amphibian Species of the World, American Museum of Natural History).

See a video of feeding using the gape and suck mechanism (Heiss et al. 2013).

This species was featured as News of the Week on 4 June 2018:

Giant salamanders in China are in trouble because of a combination of exploitation for food and intense captive breeding activities that have mixed genetically distinct groups across its known range. Yan et al. (2018) shows that the animals currently known as Andrias davidianus should be split into at least five different cryptic species. Chinese giant salamanders have been farm-raised for their meat with the government encouraging the release of some individuals in a misguided conservation attempt. However, the farm-raised individuals were bred without consideration of genetics and their release could result in the loss of genetic distinctness, merging the five species into one. Further Turvey et al. (2018) presents a dismal picture of the current status of wild populations; despite intense field work, a seasoned group of biologists were only able to find no more than a handful of individuals. Governmental action will be required to preserve those few wild populations that still exist (Written by David B. Wake & Ann T. Chang).

This species was featured as News of the Week on 8 July 2019:

Amphibians have a long history of medical use with many innovations still to be discovered. Building off of traditional uses, Deng et al. (2019) explored the use of skin secretions from Andrias davidianus (SSAD), which can be humanely collected twice a month, as a medical adhesive. Current methods of wound closure include mechanical closures (e.g., staples and sutures) and adhesive closure materials (e.g., synthetic polymers and naturally derived fibrin glue from mussels). Using freeze-dried then rehydrated SSAD, Deng et al. compared the effectiveness of these different wound closure materials in ex vivo and in vivo (in rats) experiments. They found that SSAD adhered tissue equal to or better than other adhesive materials and was more flexible. Additionally, SSADs had the best wound healing times with regenerative properties and minimal scarring than all of the other methods. SSAD also degenerated quickly in live tissue with a minimal immune response. Testing is still needed to determine how SSADs will interact with human tissues, but these results have exciting implications for post surgery recovery (Written by Ann T. Chang).

This species was featured as News of the Week on 23 September 2019:

How sex is determined in amphibians is epitomized by diversity. For those species with genetic sex determination, which sex has two types of sex chromosomes (e.g., XY or ZW chromosomes as in mammals and birds, respectively) varies from species to species. To date, most research on the genetics of amphibian sex determination has focused on frogs with little work centered on the salamanders or caecilians. New research by Hime et al (2019) identified a ZZ-ZW female heterogametic sex chromosome system in the salamander family Cryptobranchidae, which includes Cryptobranchus hellbenders from the United States and Andrias giant salamanders from Asia. Using next generation genomic data, the same ZZ-ZW sex-linked regions were discovered in the genomes of both salamander genera. This discovery indicates that the same sex chromosomes have been retained in Cryptobranchid salamanders since the different species diverged roughly 60 million years ago. Their work is particularly impressive given these salamanders’ genomes are enormous at 56 Gb, roughly 18 times the size of the human genome. Beyond the evolutionary implications of understanding a remarkably conserved sex chromosome system in an ancient salamander lineage, they produced a series of sex-linked molecular markers that are sequenced only in genetic females, which will facilitate conservation work on these imperiled amphibians (Written by Max Lambert).

References

Chang, M. L. Y. (1936). Contribution à l'étude morphologique, biologique et systèmatique des amphibiens urodèles de la Chine. Librairie Picart, Paris.

Fei, L. (1999). Atlas of Amphibians of China. Henan Publishing House of Science and Technology, Zhengzhou.

Haker, K. (1997). "Haltung und Zucht des Chinesischen Riesensalamanders Andrias davidianus." Salamandra, 33, 69-74.

Kawamichi, T. and Ueda, H. (1998). ''Spawning at nests of extra-large males in the Giant Salamander Andrias japonicus.'' Journal of Herpetology, 32, 133-136.

Liu, C.C. (1950). Amphibians of Western China. Chicago Natural History Museum, Chicago.

Liu, G., and Q. Liu (1998). ''Andrias davidianus (Blanchard, 1871).'' China Red Data Book of Endangered Animals. Amphibia and Reptilia. Zhao, E., eds., Science Press, Beijing, China, 30-33.

Thorn, R. (1969). Les Salamandres d'Europe, d'Asie, et d'Afrique du Nord. Lechevalier, Paris, France.

Ye, C., Fei, L., and Hu, S. Q. (1993). Rare and Economic Amphibians of China. Sichuan Publishing House of Science and Technology, Chengdu.

Zhao, E. (1999). ''Distribution patterns of amphibians in temperate East Asia.'' Patterns of Distribution of Amphibians. A Global Perspective. Duellman, W. E., eds., Johns Hopkins University Press, Baltimore, MD, 421-443.

Zhao, E. (ed.) (1998). China Red Data Book of Endangered Animals. Amphibia and Reptilia. Science Press, Beijing, China.

Species Account Citation: AmphibiaWeb 2022 Andrias davidianus: Chinese Giant Salamander <https://amphibiaweb.org/species/3858> University of California, Berkeley, CA, USA. Accessed Nov 21, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 21 Nov 2024.

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