Portal:Amphibians
The Amphibian Portal
Amphibians are ectothermic, anamniotic, four-limbed vertebrate animals that constitute the class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all tetrapods excluding the amniotes (tetrapods with an amniotic membrane, such as modern reptiles, birds and mammals). All extant (living) amphibians belong to the monophyletic subclass Lissamphibia, with three living orders: Anura (frogs and toads), Urodela (salamanders), and Gymnophiona (caecilians). Evolved to be mostly semiaquatic, amphibians have adapted to inhabit a wide variety of habitats, with most species living in freshwater, wetland or terrestrial ecosystems (such as riparian woodland, fossorial and even arboreal habitats). Their life cycle typically starts out as aquatic larvae with gills known as tadpoles, but some species have developed behavioural adaptations to bypass this.
Young amphibians generally undergo metamorphosis from an aquatic larval form with gills to an air-breathing adult form with lungs. Amphibians use their skin as a secondary respiratory interface and some small terrestrial salamanders and frogs lack lungs and rely entirely on their skin. They are superficially similar to reptiles like lizards, but unlike reptiles and other amniotes, require access to water bodies to breed. With their complex reproductive needs and permeable skins, amphibians are often ecological indicators to habitat conditions; in recent decades there has been a dramatic decline in amphibian populations for many species around the globe.
The earliest amphibians evolved in the Devonian period from tetrapodomorph sarcopterygians (lobe-finned fish with articulated limb-like fins) that evolved primitive lungs, which were helpful in adapting to dry land. They diversified and became ecologically dominant during the Carboniferous and Permian periods, but were later displaced in terrestrial environments by early reptiles and basal synapsids (predecessors of mammals). The origin of modern lissamphibians, which first appeared during the Early Triassic, around 250 million years ago, has long been contentious. The most popular hypothesis is that they likely originated from temnospondyls, the most diverse group of prehistoric amphibians, during the Permian period. Another hypothesis is that they emerged from lepospondyls. A fourth group of lissamphibians, the Albanerpetontidae, became extinct around 2 million years ago. (Full article...)
Selected frog article
The Arthroleptidae /ˌɑːrθroʊˈlɛptɪdiː/ are a family of frogs found in sub-Saharan Africa. This group includes African treefrogs in the genus Leptopelis along with the terrestrial breeding squeakers Arthroleptis, and several genera restricted to the Guinean forests of central and west Africa, such as the hairy frog (Trichobatrachus). (Full article...)
Selected salamander article
The Cryptobranchoidea are a suborder of salamanders found in Asia, European Russia, and the United States. They are known as primitive salamanders, in contrast to Salamandroidea, the advanced salamanders. It has two living subdivisions, Cryptobranchidae (Asian giant salamanders and hellbenders), and Hynobiidae, commonly known as Asian salamanders.
Giant salamanders are obligate paedomorphs with partial metamorphosis, but Asiatic salamander goes through a full metamorphosis. The only known exceptions are the Longdong stream salamander, which has been documented as facultatively neotenic, and the Ezo salamander, where a now assumed extinct population from Lake Kuttarush in Hokkaido had neotenic traits like gills in adults.
The oldest members of the group are known from the Middle Jurassic (Bathonian) aged Yanliao Biota of China. (Full article...)
List of selected salamander articles
|
|---|
Did you know? –
- ... that the caecilians Chthonerpeton indistinctum and Typhlonectes compressicauda (pictured) both give birth to live young?
- ...that the Desert Tree Frog is one of Australia's most widely distributed frogs?
- ... that eggs of the greenhouse frog are laid on land and have been found under a flower pot?
- ... that the black jumping salamander, the dwarf false brook salamander, the admirable false brook salamander, the Smith's false brook salamander and Thorius pennatulus are all endemic to Mexico, and critically endangered?
- ... that the male polkadot poison frog guards the eggs laid by the female and carries the newly hatched tadpoles to water?
Selected amphibian type
A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order Anura (coming from the Ancient Greek ἀνούρα, literally 'without tail'). Frog species with rough skin texture due to wart-like parotoid glands tend to be called toads, but the distinction between frogs and toads is informal and purely cosmetic, not from taxonomy or evolutionary history.
Frogs are widely distributed, ranging from the tropics to subarctic regions, but the greatest concentration of species diversity is in tropical rainforest and associated wetlands. They account for around 88% of extant amphibian species, and are one of the five most diverse vertebrate orders. The oldest fossil "proto-frog" Triadobatrachus is known from the Early Triassic of Madagascar (250 million years ago), but molecular clock dating suggests their divergence from other amphibians may extend further back to the Permian, 265 million years ago.
Adult frogs have a stout body, protruding eyes, anteriorly-attached tongue, limbs folded underneath, and no tail (the "tail" of tailed frogs is an extension of the male cloaca). Frogs have glandular skin, with secretions ranging from distasteful to toxic. Their skin varies in colour from well-camouflaged dappled brown, grey and green, to vivid patterns of bright red or yellow and black to show toxicity and ward off predators. Frog skin also has a rich microbiome which is important to their health. Adult frogs live in both fresh water and on dry land; some species are adapted for living underground or in trees. As their skin is semi-permeable, making them susceptible to dehydration, they either live in moist niches or have special adaptations to deal with drier habitats. Frogs produce a wide range of vocalisations, particularly in their breeding season, and exhibit many different kinds of complex behaviors to attract mates, to fend off predators and to generally survive. (Full article...)
List of selected amphibian type articles
|
|---|
Selected images
-
A male Dendropsophus microcephalus frog, displaying its vocal sac—membranes of skin under the throat or on the corner of the mouth that distend to amplify its call. The species lives in moist areas in most of Central America and northern South America. -
Photo: Charles H. Smith, USFWSThe golden toad (Bufo periglenes) is an extinct species of true toad that was once abundant in a small region of high-altitude cloud-covered tropical forests, about 30 km2 (12 sq mi) in area, above the city of Monteverde, Costa Rica. The last reported sighting of a golden toad was on 15 May 1989. Its sudden extinction may have been caused by chytrid fungus and extensive habitat loss. -
Photograph: H. KrispThe phantasmal poison frog (Epipedobates tricolor) is a species of poison dart frog endemic to Ecuador. First described by George Albert Boulenger in 1899, this endangered species is found only in rainforests on the slopes of the Andes. -
Photo: Benny TrappAn Italian tree frog (Hyla intermedia) with an inflated vocal sac. Vocal sacs, flexible membranes of skin possessed by most male frogs, are generally used to amplify mating or advertisement calls. However, some species in the family Rhinodermatidae may also use the sac to store or transport their tadpoles. -
Photo credit: Patrick CoinA terrestrial subadult Eastern newt or red eft (Notophthalmus viridescens). Salamanders of the family Salamandridae with aquatic adult stages are called newts. Some newts, including the Eastern newt, have a juvenile terrestrial stage called the eft. The red eft has bright aposematic coloration to warn predators of its highly toxic skin. -
Photograph credit: RushenbWallace's flying frog (Rhacophorus nigropalmatus) is a moss frog found in tropical southeastern Asia. It is named after the British naturalist Alfred R. Wallace, who collected the first known specimen of the species. It lives almost exclusively in trees, and when threatened, or in search of prey, will leap from a branch and splay its four webbed feet; the membranes between its toes and the loose skin flaps on its sides catch the air as it falls, helping it to glide. This individual was photographed in Khao Sok National Park, Thailand. -
Photograph: Benny TrappThe Epirus water frog (Pelophylax epeiroticus) is a species of frog in the family Ranidae. It is found in western Greece, including Corfu, and the southern areas of Albania. The species is collected from the wild for human consumption. -
Photo credit: Fir0002The Eastern Banjo Frog (Limnodynastes dumerilli) is native to eastern Australia and has been introduced to New Zealand. The frog is also commonly called the pobblebonk after its distinctive "bonk" call, which is likened to a banjo string being plucked. Adults are roughly seven to eight cm long. -
Photograph: Benny TrappThe Iberian midwife toad (Alytes cisternasii) is a species of frog in the family Alytidae found in Portugal and western Spain. Its natural habitats are temperate forests and shrubland, Mediterranean-type shrubby vegetation, intermittent rivers and freshwater marshes, pastureland, and aquaculture ponds. The species is affected by habitat loss, and the IUCN lists it as being "Near Threatened". -
The fire salamander (Salamandra salamandra) is a European salamander species with a long lifespan. These nocturnal animals generally eat various insects, spiders, earthworms and slugs, but they also occasionally eat newts and young frogs. -
Photo: Marie-Lan NguyenThe marsh frog (Pelophylax ridibundus) is a species of true frog and the largest frog native to Europe; females of this sexually dimorphic species may be up to 17 centimetres (6.7 in) long. The marsh frog feeds mainly on insects, but it also eats smaller amphibians, fish, and rodents. -
The edible frog (Pelophylax kl. esculentus) is a fertile hybrid of the pool and marsh frogs which is commonly found in Europe. The species is commonly used in food, including the French delicacy frog legs. -
Photograph: Benny TrappThe Spanish painted frog (Discoglossus jeanneae) is a species of frog in the family Alytidae. Endemic to Spain, it mostly lives in open areas, pine groves and shrublands. It feeds mostly on insects and worms. -
Photo credit: LiquidGhoulThe New England Tree Frog (Litoria subglandulosa) is a species of frog native to the streams of the New England Tablelands, New South Wales, Australia. -
Illustration credit: Ernst HaeckelA frog is an amphibian characterized by long hind legs, a short body, webbed digits, protruding eyes and the absence of a tail. Frogs are most noticeable through their call, which can be widely heard during the mating season. It is estimated that up to 20% of amphibian species may care for their young in one way or another, and there is a great diversity of parental behaviours. For example, frogs in the Gastrotheca genus (upper left) carry their eggs in a pouch, and females of the Eleutherodactylus lineatus species (center left) carry their young on their back.
.jpg)
_jeannaea.jpg)
Selected toad article
Couch's spadefoot toad or Couch's spadefoot (Scaphiopus couchii) is a species of North American spadefoot toad (family Scaphiopodidae). The specific epithet couchii is in honor of American naturalist Darius Nash Couch, who collected the first specimen while on a personal expedition to northern Mexico to collect plant, mineral, and animal specimens for the Smithsonian Institution. (Full article...)
Selected caecilian article
Dermophis is a genus of worm-like amphibians in the family Dermophiidae, the Neotropical and Tropical African caecilians. They are found in the Middle America between southern Mexico and northwestern Colombia. Common names Mexican caecilians or Neotropical caecilians are sometimes used for them. (Full article...)
Need help?
Do you have a question about Amphibians that you can't find the answer to?
Consider asking it at the Wikipedia reference desk.
Topics
Subcategories
Related portals
Associated Wikimedia
The following Wikimedia Foundation sister projects provide more on this subject:
-
Commons
Free media repository -
Wikibooks
Free textbooks and manuals -
Wikidata
Free knowledge base -
Wikinews
Free-content news -
Wikiquote
Collection of quotations -
Wikisource
Free-content library -
Wikiversity
Free learning tools -
Wiktionary
Dictionary and thesaurus
