Amphibians (class Amphibia) are a taxon of animals that include all tetrapods, four-legged vertebrates, that do not have amniotic eggs.(from Greek αμφις "both" and βιος "life") are ectotherms, and generally spend part of their time on land, but most do not have the adaptations to an entirely terrestrial existence found in most other modern tetrapods (amniotes). There are around 6,000 described, living species of amphibians. The study of amphibians and reptiles is known as herpetology.

History of amphibians

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Amphibians developed with the characteristics of pharyngeal slits/gills, a dorsal nerve cord, a notochord, and a post-anal tail at different stages of their life. Though early tetrapods (which appeared 390 million years ago in the Devonian period) are often referred to as "amphibians", the first true amphibians (of the order Temnospondyli) appeared during the early Carboniferous period. During the late Carboniferous, Permian and Triassic periods, amphibians were extremely diverse, including many large and small forms, some newt and salamander-like, others resembling snakes or eels, and some large-snouted forms that were very like small (about 1.5 meter long) crocodiles (e.g. Archegosaurus). The drying out of the coal swamps during the latest Carboniferous and again at the end of the Early Permian diminished many of the environments of these Paleozoic amphibians, with the result that many types died out, and they were supplanted by reptiles. However both large and small amphibians still continued to flourish in rivers and lakes of the Late Permian, alongside the diverse therapsids or mammal-like reptiles that were the dominant land animals of that time. During the following, Triassic period, there were many genera with large, sometimes very flattened heads and very weak limbs; some of these, like Paracyclotosaurus, Cyclotosaurus and Mastodonsaurus were several meters in length. Apart from a few stragglers, all these large amphibians died out at the Triassic-Jurassic extinction event, and the majority of Jurassic amphibians belonged to modern groups, and would look familiar today.

Throughout their history, amphibians have ranged in size from large forms, such as the above mentioned Triassic genera, the 5 foot (150cm) long Eryops of the Permian period, and the Giant Japanese and Chinese Salamanders of today, down to the tiny Brachycephalus didactylus (Brazilian Gold Frog) and Eleutherodactylus iberia (leptodactylid frog) from Cuba, with a total length of 9.6-9.8 millimeters (0.4 inches). Amphibians have mastered almost every climate on earth from the hottest deserts to the frozen arctic.

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Is it true @oleuanna that the slug's off to a land full of mollusc eating amphibia?
SimonMagus (Simon Cooke) Tue, 03 Nov 2009 20:41:40 -0000
Is it true @oleuanna that the slug's off to a land full of mollusc eating amphibia?
RT @mancini: Qué falta y qué sobra en una redacción online http://www.amphibia.com.ar/4522 @Lauracadabra
luisarestrepo (Luisa Restrepo) Tue, 03 Nov 2009 16:25:54 -0000
RT @mancini: Qué falta y qué sobra en una redacción online http://www.amphibia.com.ar/4522 @Lauracadabra
Man causes extinction-crises Amphibia ( Mens veroorzaakt uitstervingscrisis amfibieën ) : http://bit.ly/1sokK1
Mazzul (Mazzul) Tue, 03 Nov 2009 07:41:23 -0000
Man causes extinction-crises Amphibia ( Mens veroorzaakt uitstervingscrisis amfibieën ) : http://bit.ly/1sokK1
Amphibia nos trae "El negocio de la información"; otra visión sobre el cierre de Soitu y ADN... http://tinyurl.com/yhn6z7s
ulibarri (ulibarri) Mon, 02 Nov 2009 17:19:14 -0000
Amphibia nos trae "El negocio de la información"; otra visión sobre el cierre de Soitu y ADN... http://tinyurl.com/yhn6z7s
♫ Solea Amphibia - Samph
groovesalad (somafm groove salad) Sun, 01 Nov 2009 21:24:05 -0000
♫ Solea Amphibia - Samph
Soitu, BBVA and Ford T, over @Amphibia http://bit.ly/3H4TdA
RoddyOr (RoddyOr) Sat, 31 Oct 2009 01:10:47 -0000
Soitu, BBVA and Ford T, over @Amphibia http://bit.ly/3H4TdA

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