Giant salamander
| Giant salamander | ||||||||||||
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Japanese giant salamander ( Andrias japonicus ) |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Cryptobranchidae | ||||||||||||
| Fitzinger , 1826 |
The giant salamander (Cryptobranchidae) are a very primitive family in the order of salamanders . These are permanent larvae with a partial transformation (partial neoteny ). The two genera are recently distributed in East Asia and North America. In the Miocene , the genus Andrias also occurred in today's Europe. Their closest relatives are the angular newts (Hynobiidae).
features
The Chinese giant salamander ( Andrias davidianus ) and the Japanese giant salamander ( Andrias japonicus ) are the largest and heaviest amphibians living today with a body length of over 1.5 meters and a weight of more than 20 kilograms; the American mud devil ( Cryptobranchus alleganiensis ) is about half the size. For Andrias sligoi a length of up to 180 centimeters is postulated; It is questionable whether this information from the 1930s can still be found in today's specimens.
The spine of the giant salamander consists of amphicoel (front and back hollowed out) vertebrae; her skull bone has no tear bones . They have four rather short limbs and stand out due to their massive, fleshy shape and their extremely wide, flat head and body. The trunk, limbs and the laterally flattened, relatively short tail have wide skin seams or bulges. The eyes, which are far out, are very small, lidless and degenerate in their performance.
The external gills that exist in youth are largely regressed in the third year of life and give way to lung , skin and intestinal breathing . In the genus Cryptobranchus , however, two of the four internal gill arches of the larval phase remain, with the gill holes being closed; with Andrias a couple remains open. The absence of eyelids and the retention of the larval teeth in the adult animals are also characteristics of an incomplete metamorphosis . Instead of eyesight, the senses of touch and smell play an important role.
Occurrence, way of life
Andrias davidianus is widespread in the catchment area of the Yangtze River , Andrias sligoi lives in the catchment area of the Pearl River , a third so far not yet described Chinese giant salamander species occurs in streams and rivers that spring from the Huang Shan Mountains, and Andrias japonicus lives in southern and central Japan .
Cryptobranchus alleganiensis is found in the eastern and central US : the subspecies ssp. alleganiensis in south and southwest New York state , south Illinois , northeast Mississippi, and north Alabama and Georgia , the disjoint subspecies ssp. bishopi in southeast Missouri and Arkansas .
Giant salamanders have lived in aquatically clean, cool streams and sometimes also in larger rivers and mountain lakes. They appear rather sluggish and hide on the bottom after passing prey such as fish, other tailed amphibians, frogs, crustaceans, earthworms and aquatic insects. They are mostly active at night.
Mud devils are very defensive and quite vicious towards people when they feel threatened.
Reproduction
The reproduction in late summer takes place in a very peculiar way for amphibians . The male digs a shallow nest out of the ground into which it then lets females ready to spawn. These lay two spawning cords each several meters long from up to 600 elongated eggs, which are then immediately inseminated by the male. The clutch is guarded by the father; the females are now also kept away as potential spawners. The larvae hatch after two to three months with a size of three centimeters and already existing gill tufts and limbs.
Threat and species protection
Because giant salamanders are considered a delicacy in their Asian homeland and are also used in folk medicine , they were hunted by bait fishing almost to extinction. Their habitats were also partially destroyed or often polluted. Today they are strictly protected in Japan and partly in China.
The genus Andrias is listed in Appendix I of the Washington Convention on Endangered Species (CITES). Any trade in these animals is prohibited.
Research history
In 1726, the Swiss Johann Jakob Scheuchzer (1672–1733), Zurich city doctor and naturalist, found the fossilized skeleton of a giant salamander ( Andrias Scheuchzeri ) about one meter in size, living 14 million years ago, on the Schiener Berg in the Öhninger Kalken, today the district of Konstanz , Baden-Württemberg . However, Scheuchzer believed at the time that he was looking at the skeleton of a person who perished in the flood ( Homo diluvii ). It was not until 1837 that Johann Jakob von Tschudi realized that the skeleton was actually a huge, extinct salamander .
The first Japanese giant salamander was only brought to Europe in 1829 by Philipp Franz von Siebold , to Leiden , where it lived on for 52 years. This suggests that these animals can get very old. Since then, giant salamanders have been popular exhibits for zoological gardens. As early as 1863, Baedeker referred to a specimen of the Cryptobranchus Japonicus in the volume Belgium and Holland as a special attraction in the Amsterdam zoo , which not even the London zoo owns.
Taxonomy
- Genus Aviturus Gubin, 1991
- Species Aviturus exsecratus (Gubin, 1991) †, lived in Mongolia 56 million years ago
- Genus Andrias Tschudi, 1837 - Asian giant salamanders
- Species Andrias davidianus (Blanchard, 1871) - Chinese giant salamander
- Species Andrias japonicus (Temminck, 1836) - Japanese giant salamander
- Art Andrias Scheuchzeri (Tschudi, 1837) †
- Art Andrias sligoi (Boulenger, 1924)
- Species Andrias sp.
- Genus Chunerpeton Gao & Shubin, 2003 †
- Art Chunerpeton tianyiensis Gao & Shubin, 2003 †, lived in the Middle Jurassic in Mongolia
- Genus Cryptobranchus Leuckart, 1821 - American giant salamander
- Art Cryptobranchus alleganiensis (Daudin, 1803) - Hellbender , Hellbender
| See also amphibian systematics , with references to the amphibian taxonomy used here. Furthermore information on a new, phylogenetically based systematic model. |
Trivia
The title-giving newts in the novel The War with the Newts (1936) by the Czech writer Karel Čapek are assigned to the species Andrias Scheuchzeri .
Individual evidence
- ↑ a b c d Samuel T. Turvey, Melissa M. Marr, Ian Barnes, Selina Brace, Benjamin Tapley, Robert W. Murphy, Ermi Zhao and Andrew A. Cunningham. 2019. Historical Museum Collections Clarify the Evolutionary History of Cryptic Species Radiation in the World's Largest Amphibians. Ecology and Evolution. DOI: 10.1002 / ece3.5257
- ↑ a b Tschudi, JJ v. 1837. About Homo diluvii testis, Andrias Scheuchzeri. New yearbook for mineralogy, geognosy, geology and petrefacts customer. Stuttgart 5: 545-547. Retrieved October 1, 2012 .
- ^ Belgium and Holland. Guide for travelers . Karl Baedeker Verlag, Coblenz 1863, 8th edition, p. 264
- ↑ Gubin, YM (1991). Paleocene salamanders from southern Mongolia. Paleontological Journal, 1991, 91-102.
- ↑ Michael Seifert: The great giant salamander was versatile. (PDF; 287 kB) In: Press release. University of Tübingen and Senkenberg Institute, August 21, 2012, accessed on October 1, 2012 .
- ^ Gao, KQ and Shubin, NH, 2003. Earliest known crown-group salamanders : Nature. 422, 424-428. doi: 10.1038 / nature01491
literature
- Naumann, Göbel: Knowledge compact - amphibians and reptiles , VEMAG, Cologne, ISBN 3-625-21133-5
