Mud devil
| Mud devil | ||||||||||||
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Mud devil ( Cryptobranchus alleganiensis ) |
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| Scientific name of the genus | ||||||||||||
| Cryptobranchus | ||||||||||||
| Leuckart , 1821 | ||||||||||||
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| Cryptobranchus alleganiensis | ||||||||||||
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The mud devil ( Cryptobranchus alleganiensis ) is the only species of the monotypic genus Cryptobranchus . Along with the Chinese giant salamander ( Andrias davidianus ) and the Japanese giant salamander ( Andrias japonicus ), it is the third recent species of the giant salamander family (Cryptobranchidae) and lives in North America in large flowing waters with stony bottoms.
Etymology and history of research
The generic name Cryptobranchus is made up of the ancient Greek κρυπτός (kryptós): "hidden", "secret" and βράγχια (bránchia): "gill". The additional species " alleganiensis " refers to the type area in the Allegheny Mountains , whereby the French spelling used first in the first description has established itself as the correct species name. The part of the name " bishopi " honors the American herpetologist Sherman C. Bishop .
There are numerous trivial names for the species in US-American usage . In addition to the most frequently used name “hellbender”, it is also known as “mud-devil”, “ground-puppy”, “water-dog”, “leverian water newt”. , "Alligator", "little alligator", "Allegheny alligator", "young alligator", "alligator of the mountains", "big water lizard", "devil dog" or "walking catfish". The German trivial name "Schlammteufel" is a literal translation of the English "mud-devil" according to Oken .
A first illustration and description of the mud devil was published in 1801 by Sonnini de Manoncourt and Latreille under the name "La Salamandre des monts Alléganis". However, a work by François-Marie Daudin , who named the species Salamandra alleganiensis , published two years later, is considered the officially valid first description . Both works were based on a specimen copy brought to Paris by the French botanist and explorer André Michaux .
After he had already pointed this out in other writings, under various names, Benjamin Smith Barton published a further description of the species in 1814, for which he now proposed the name Salamandra gigantea . Although he knew that Michaux had brought a specimen to Paris, he did not know the corresponding descriptions by the French scientists. Barton also mentioned some common names, including "Hell-Bender," noting that the name was derived from the slaves in western Virginia who believed that the slowly winding movements of the animals looked like they were in agony. As a name from the language of the indigenous population , he cited " To-ko-meg" ( Chippewa ) and "Techselk" or "Tweeg" ( Delaware ). Barton apparently preferred the latter variant and used it throughout his work, but could not give any information on the etymology of the term.
In 1821 Friedrich Andreas Sigismund Leuckart placed Salamandra gigantea as Cryptobranchus salamandroides in the genus Cryptobranchus that he had newly established . He was referring only to Barton's work. The descriptions of the French scientists continued to go unnoticed. Richard Harlan calls the species Abranchus alleghaniensis in 1825, but assigns the origin of the species addition to Michaux and not Daudin. Jan van der Hoeven used the combination Cryptobranchus alleghaniensis for the first time in 1837 , albeit with a different spelling of the species addition. It was not until 1917 that Stejneger and Barbour first used the spelling commonly used today and correctly referred to Daudin as the first descriptor.
In 1943 Arnold B. Grobman described a second species of the genus Cryptobranchus from the Ozarks as Cryptobranchus bishopi . Its status as an independent species was discarded in 1953 and the population living in isolation in the Ozarks was classified as the second subspecies Cryptobranchus alleganiensis bishopi next to Cryptobranchus alleganiensis alleganiensis . Molecular genetic studies from 2011 showed clear differences between the two subspecies, but also great differences between two subpopulations of Cryptobranchus alleganiensis bishopi . A re-establishment of the "Ozark Hellbender" as an independent species Cryptobranchus bishopi was considered by the authors of the study, but was not considered feasible. Cryptobranchus alleganiensis remained the only species in the genus.
features
Mud devils, like all representatives of the giant salamanders , have a very flat body and head, small eyes without lids, thick folds of skin on the flanks and short legs with four toes in front and five toes behind. The tail is laterally flattened and rudder-shaped. The vertebrae are amphicoel (with funnel-shaped indentations at both ends) and the cranial skeleton lacks the lacrimal bone as well as the septomaxilla and the thyroid bone . The arrangement of the inner row of teeth on the ploughshare leg in the form of an arch parallel to the outer row of teeth of the maxilla is a relic of the larval stage ( pedomorphism ). Lungs are present, but breathing is mainly through the skin with its thick folds on the flanks.
The mud devil differs from its Asian relatives of the genus Andrias in particular in that it maintains a cleft gill on both sides of the neck.
Information about the different body sizes of males and females of the mud devil is contradicting itself. While some authors find the females significantly larger in terms of length and body mass, other works show no significant differences between the sexes. The largest known animal had a total body length of 74 cm, but the average total body length of the adult animals is 29-60 cm. They can reach a body mass of up to 1 kg.
Subspecies and distribution areas
The two subspecies of Cryptobranchus alleganiensis occur in two separate areas of distribution in the eastern and central United States :
Cryptobranchus alleganiensis alleganiensis
The nominate form is also known as "Eastern Hellbender" and is the larger of the two subspecies with an average length of 45–60 cm. The gill slits are relatively large, the lateral line organ has wart-like elevations in the area of the pelvic girdle and the back is covered with dark spots rather than larger spots.
This subspecies inhabits the rivers and streams in the Ohio and Tennessee basins along the Appalachian Mountains . The main distribution area extends from New York to Missouri and in the south to Georgia . A disjoint population lives in eastern central Missouri in rivers in the Missouri and Meramec catchments that drain the area to the north.
Cryptobranchus alleganiensis bishopi
The "Ozark Hellbender" remains slightly smaller than the "Eastern Hellbender" with an average length of 29–57 cm. It differs from the "Eastern Hellbender" through the smaller gill slits, a smoother side line in the pelvic area and clear dark spots on the back.
This subspecies forms a disjoint population in the Ozark Plateau area of southern Missouri and northeast Arkansas. It lives exclusively in the catchment area of the White River , which drains the area to the south.
Way of life
Mud devils live completely aquatic and are predominantly nocturnal, although, especially with Cryptobranchus alleganiensis alleganiensis , activity during the day has often been observed. Like all adult representatives of the giant salamanders, they show a pronounced territorial behavior whereby the territories of the females are usually smaller than those of the males. Especially during the mating season, the territories are defended against conspecifics in sometimes fierce battles, which often lead to injuries.
Average life expectancy is around 20–30 years.
Habitat
As a habitat, they prefer cool, rapidly flowing, oligotrophic waters with a stony bottom at altitudes of up to 750 m above sea level.
nutrition
Like all representatives of the giant salamanders, mud devils are mainly ambulance hunters who kill their prey by sucking. Their preferred prey are crayfish . In areas where these are rare, they will also eat lampreys , small fish, insects, worms, snails or tadpoles, and fish spawn. Carrion is also not spurned and there are credible reports of cannibalism. The food requirement is low in relation to body size.
Reproduction
Mud devils reach sexual maturity at the age of four to six years, with a total length of about 40 cm. The mating season begins in September to October, but can shift to December or January depending on the subspecies and population.
At the beginning of the mating season, the males create shallow nesting hollows, usually under large stones, and present themselves to the females ready to mate. The females lay cords with 200 to 550 eggs with a diameter of about 6.5 mm in the pit. As with all giant salamanders, fertilization takes place externally. Sometimes it happens that several females lay their eggs in the nesting trough of the same male, so that clutches with up to 2000 eggs can arise. The spawn is guarded by the males, supplied with oxygen-rich water by tail strokes and defended against cannibalistic conspecifics.
The larvae hatch, depending on the water temperature, after about two to three months with a body length of around 2.5 cm. Only at the age of around 1.5–2 years, with a total body length of 10–13 cm, have the external gill tufts of the larvae completely regressed.
Danger
In the USA, the subspecies Cryptobranchus alleganiensis bishopi has been listed as "endangered" in the sense of the Endangered Species Act since 2011 and the subspecies Cryptobranchus alleganiensis alleganiensis has been listed as a candidate for the classification "threatened" since 2013 . The species is classified as "Near Threatened" by the IUCN , as there has been a decline in populations.
Individual evidence
- ↑ a b c d e f g h i HA Dundee: Cryptobranchus, and C. alleganiensis. In: Catalog of American Amphibians and Reptiles (CAAR) , entry 101, 1971, pp. 101.1-101.4, ( digitized version ).
- ↑ F. Hemming (Ed.): Direction 56: Completion and in certain cases correction of entries relating to the names of genera belonging to the classes Pisces, Amphibia and Reptilia made in the "Official List of Generic Names in Zoology" in the period up to the end of 1936. In: Opinions and Declarations Rendered by the International Commission on Zoological Nomenclature , Volume 1, Section D, Part D.17, 1956, p. 353, ( digitized version ).
- ^ A b MA Nickerson & Ch. E. Mays: The Hellbenders: North American "Giant Salamanders". Milwaukee Public Museum, 1973, p. 57, ( digitized ).
- ↑ L. Oken: General natural history for all classes. Volume 6, Hoffmann'sche Verlags-Buchhandlung, Stuttgart, 1836, p. 449, ( digitized version ).
- ↑ a b CS Sonnini de Manoncourt & PA Latreille: Histoire Naturelle des Reptiles, avec Figures dissinées d'après Nature. Volume 4, Paris, 1801, p. 253, ( digitized version ).
- ↑ a b F.-M. Daudin: Histoire Naturelle, Générale et Particulière des Reptiles; Ouvrage Faisant suit à l'Histoire Naturelle Générale et Particulière, Composée par Leclerc de Buffon; et Rédigée par CS Sonnini, Membre de Plusieurs Sociétés Savantes. Volume 8, Paris, 1803, pp. 231-232, ( digitized version ).
- ↑ BS Barton: A Memoir concerning an animal of the class of reptilia, or amphibia, which is known in the United States, by the names of Alligator and Hell-Bender. Philadelphia, 1814, 26 pp. + 1 plate, ( digitized ).
- ↑ S. Leuckart: Some about the fish-like amphibians. In: Isis von Oken , Volume 9, 1821, pp. 257-265, ( digitized version ).
- ^ R. Harlan: Observations on the genus Salamandra, with the anatomy of the Salamandra gigantea (Barton) or S. Alleghaniensis (Michaux) and two new genera proposed. In: Annals of the Lyceum of Natural History of New-York , Volume 1, 1825, pp. 223-234, ( digitized ).
- ^ LH Stejneger & T. Barbour: A check list of North American amphibians and reptiles. Harvard University Press, Cambridge, 1917, p. 7, ( digitized version ).
- ^ AB Grobman: Notes on Salamanders with the Description of a New Species of Cryptobranchus. In: Occasional Papers of the Museum of Zoology - University of Michigan , Number 470, 1943, pp. 1-13, ( digitized ).
- ↑ a b c d e f RS Crowhurst, KM Faries, J. Collantes, JT Briggler, JB Koppelman & LS Eggert: Genetic relationships of hellbenders in the Ozark highlands of Missouri and conservation implications for the Ozark subspecies (Cryptobranchus alleganiensis bishopi). In: Conservation Genetics , Volume 12, 2011, pp. 637-646, ( digitized ).
- ↑ a b c d RK Browne, H. Li, Z. Wang, S. Okada, P. Hime, A. McMillan, M. Wu, R. Diaz, D. McGinnity & JT Briggler: The giant salamanders (Cryptobranchidae): Part A. palaeontology, phylogeny, genetics, and morphology. In: Amphibian and Reptile Conservation , Volume 5, Number 4, 2012, pp. 17-29, ( digitized ).
- ↑ D. Vasilyan & M. Böhme: Pronounced Peramorphosis in Lissamphibians — Aviturus exsecratus (Urodela, Cryptobranchidae) from the Paleocene-Eocene Thermal Maximum of Mongolia. In: PLOS one , Volume 7, Number 9, 2012, e40665, doi : 10.1371 / journal.pone.0040665 .
- ^ A b NG Burgmeier, SD Unger, TM Sutton & RN Williams: Population Status of the Eastern Hellbender (Cryptobranchus alleganiensis alleganiensis) in Indiana. In: Journal of Herpetology , Volume 45, Number 2, 2011, pp. 195-201, ( digitized version ).
- ^ R. Makowsky, LA Wilson & Th. K. Pauley: Sexual Dimorphism in the Eastern Hellbender (Cryptobranchus alleganiensis alleganiensis). In: Herpetological Conservation and Biology , Volume 5, Number 1, 2010, pp. 44-48, ( digitized version ).
- ↑ a b c d e f g h RK Browne, H. Li, Z. Wang, S. Okada, P. Hime, A. McMillan, M. Wu, R. Diaz, D. McGinnity & JT Briggler: The giant salamanders (Cryptobranchidae): Part B. Biogeography, ecology and reproduction. In: Amphibian and Reptile Conservation , Volume 5, Number 4, 2014, pp. 30–50, ( digitized version ).
- ↑ M. Freake, E. O'Neill, S. Unger, St. Spear & E. Routman: Conservation genetics of eastern hellbenders Cryptobranchus alleganiensis alleganiensis in the Tennessee Valley. In: Conservation Genetics , Volume 19, 2018, pp. 571-585, ( digitized ).
- ↑ Cryptobranchus alleganiensis in the endangered Red List species the IUCN 2019. Posted by: Hammerson & Phillips, 2004. Accessed June 2 of 2019.
