View source for Physical World/Amphibians

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|'''Midwife toad'''


genus ''Alytes'' 

The males  carry a string of fertilised eggs on their back, hence the name "midwife"


The back of  the midwife toad is covered with small warts. These warts give off a strong  smelling poison when the toad is attacked
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|'''Natterjack toad'''


''Bufo  calamita'' 

Distinguished  from common toads by a yellow line down the middle of the back, and parallel  paratoid glands


Natterjacks  have a very loud and distinctive mating call
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|'''Cane toad'''


''Rhinella  marina'' 

Introduced to  many regions of the Pacific and the Caribbean islands as a method of  agricultural pest control. The species derives its common name from its use  against the cane beetle. The cane toad is now considered a pest and an invasive  species
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|'''Goliath frog'''


''Conraua  goliath'' 

Largest  living frog on Earth. Specimens can grow up to 32 cm (12.6 in) in  length. Found in Cameroon and Equatorial Guinea


The one in  the picture has stolen a watch!
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|'''American bullfrog'''


''Rana catesbeiana'' 

Has an olive  green back and sides. Males have yellow throats


Native to  southern and eastern parts of the United States and Canada
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|'''Paradoxical frog'''


''Pseudis paradoxa'' 

Its name  refers to the very large – up to 25 cm (10 in) long – tadpole, which  in turn becomes an ordinary-sized frog, only about a quarter of its former  length
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|'''Xenopus'''


genus ''Xenopus'' 

Commonly  known as the clawed frog


Studied as model  organisms for developmental biology, cell biology, toxicology, neuroscience  and for modelling human disease and birth defects
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|'''Chinese giant salamander'''


''Andrias  davidianus'' 

The largest salamander  and largest amphibian in the world, reaching a length of 180 cm  (5.9 ft)


A living  fossil which is classified as critically endangered
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|'''Hellbender'''


''Cryptobranchus  alleganiensis'' 

A species of giant  salamander endemic to eastern North America


It is blotchy  brown or red-brown in color, with a paler underbelly
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|'''Axolotl'''


''Ambystoma mexicanum'' 

Also known as a  Mexican salamander and colloquially known as a "walking fish"


Axolotls  reach adulthood without undergoing metamorphosis. Instead of developing lungs  and taking to land, the adults remain aquatic and gilled


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'''Great crested newt'''


''Triturus  cristatus'' 

Also known as northern crested newt


Males can be  distinguished from females by the presence of a jagged crest during the  breeding season
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