Portal:Amphibians

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The Amphibian Portal

Anaschisma

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...)

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Selected frog article

Batrachyla taeniata

Batrachylidae is a family of frogs from southern South America (Argentina and Chile). Before being recognized as a family, Batrachylidae was included as a subfamily (Batrachylinae) in the family Ceratophryidae; this is the taxonomy still suggested by the Integrated Taxonomic Information System (ITIS). (Full article...)

List of selected frog articles

Selected salamander article

Fossil of the salamander Karaurus sharovi a non-urodelan caudatan from the Middle-Late Jurassic belonging to the family Karauridae

The Caudata are a group of amphibians containing the extant salamanders (the order Urodela) and all extinct species of amphibians more closely related to salamanders than to frogs. They are typically characterized by a superficially lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults.

Disagreement exists between different authorities as to the definition of the terms "Caudata" and "Urodela". Some maintain that Urodela should be restricted to the crown group, with Caudata being used for the total group. Others restrict the name Caudata to the crown group and use Urodela for the total group. The former approach seems to be most widely adopted and is used in this article. (Full article...)

List of selected salamander articles
Ambystomatidae Cryptobranchoidea Greater siren Salamanders in folklore Salamandroidea Sexual selection in amphibians Sirenidae Urodela

Did you know? – show different entries

Illustration of a Ceylon caecilian

... that the larvae of the terrestrial Ceylon caecilian have gills and a tail fin and develop in water?
... that the Georgia blind salamander and the Dougherty Plain cave crayfish both live underground and one may prey on the other?
... that populations of the endangered Albanian water frog (pictured) are declining due to over-collection for the food industry and pet trade?
... that the Sacramento Mountain Salamander is preyed on by the western terrestrial garter snake?
... that the female common rocket frog (pictured carrying tadpoles) and the male rainforest frog Colostethus stepheni are both involved in the parental care of their young?

Selected amphibian type

Spotted salamander, Ambystoma maculatum

Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All ten extant salamander families are grouped together under the order Urodela from the group Caudata. Urodela is a scientific Latin term based on the Ancient Greek οὐρά δήλη: ourà dēlē "conspicuous tail". Caudata is the Latin for "tailed ones", from cauda: "tail".

Salamander diversity is highest in eastern North America, especially in the Appalachian Mountains; most species are found in the Holarctic realm, with some species present in the Neotropical realm. Salamanders never have more than four toes on their front legs and five on their rear legs, but some species have fewer digits and others lack hind limbs. Their permeable skin usually makes them reliant on habitats in or near water or other cool, damp places. Some salamander species are fully aquatic throughout their lives, some take to the water intermittently, and others are entirely terrestrial as adults.

This group of amphibians is capable of regenerating lost limbs as well as other damaged parts of their bodies. Researchers hope to reverse engineer the regenerative processes for potential human medical applications, such as brain and spinal cord injury treatment or preventing harmful scarring during heart surgery recovery. The remarkable ability of salamanders to regenerate is not just limited to limbs but extends to vital organs such as the heart, jaw, and parts of the spinal cord, showing their uniqueness compared to different types of vertebrates. ⁤⁤This ability is most remarkable for occurring without any type of scarring. ⁤⁤This has made salamanders an invaluable model organism in scientific research aimed at understanding and achieving regenerative processes for medical advancements in human and animal biology. (Full article...)

List of selected amphibian type articles
Frog Toad Caecilian

Selected images

Image 1
Panamanian golden frog
Photograph: Brian Gratwicke
The Panamanian golden frog (Atelopus zeteki) is a rare species of toad endemic to Panama. First described by Emmett Reid Dunn in 1933, this species was found close to mountain streams on the eastern side of the Tabasará mountain range in Coclé and Panamá Provinces, but is now critically endangered and possibly extinct in the wild.
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Image 2
Atelopus certus
Photo: Brian Gratwicke
Atelopus certus is a species of toad endemic to the Darién Province of eastern Panama. Much of its range falls within the Darién National Park, a protected area and World Heritage Site. It is classified as endangered, primarily due to the advancing wave of chytridiomycosis moving through Central America.
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Image 3
Common frog
Photo: Richard Bartz
The common frog (Rana temporaria) is found throughout much of Europe. Adults have a body length of 6 to 9 cm (2.4 to 3.5 in) and vary in colour, with the ability to lighten and darken their skin to match their surroundings. They will feed on any invertebrate of a suitable size and, apart from the breeding season, live solitary lives.
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Image 4
Fire salamander
Photo: Archaeodontosaurus
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.
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Image 5
New England Tree Frog
Photo credit: LiquidGhoul
The New England Tree Frog (Litoria subglandulosa) is a species of frog native to the streams of the New England Tablelands, New South Wales, Australia.
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Image 6
Marsh frog
Photo: Marie-Lan Nguyen
The 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.
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Image 7
Rana clamitans
Photo credit: Derek Ramsey
The American Green Frog (Rana clamitans) is native to the eastern half of the United States and Canada. Green frogs live wherever there is shallow freshwater: ponds, road-side ditches, lakes, swamps, streams and brooks. The green frog is abundant wherever it occurs.
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Image 8
Red-eyed Tree Frog
Photo credit: Carey James Balboa
The Red-eyed Tree Frog (Agalychnis callidryas) is a small-sized tree frog, reaching lengths of about 5 to 7 centimeters (3 inches), native to Neotropical rainforests in Central America. They are not poisonous and rely on camouflage to protect them. During the day, they remain motionless with their colorful parts hidden. Thus, they appear almost completely green, and well hidden among the foliage.
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Image 9
Southern brown tree frog
Photograph: JJ Harrison
The southern brown tree frog (Litoria ewingii) is a species of tree frog native to Australia found in a wide range of habitats. Reaching 45 millimetres (1.8 in), this species is generally brown, but green and green-striped morphs are also recorded.
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Image 10
Raorchestes parvulus
Photograph credit: Rushenb
Raorchestes parvulus is a small bush frog native to tropical southeastern Asia. Although the reproductive strategy of this species has not been studied, members of the family typically make a foam nest while mating in vegetation overhanging a stream. They create the foam by beating their legs, and the eggs are deposited into the nest and covered with seminal fluid before the foam hardens into a protective casing. When the eggs hatch, the young push their way out of the nest and fall into the water below.

This picture shows a male R. parvulus frog, photographed in Phu Kradueng National Park, Thailand, calling by inflating its vocal sac.
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Image 11
Common toads in amplexus
Photo: Bernie Kohl
Two common toads (Bufo bufo) in amplexus, a form of pseudocopulation found in amphibians and limulids. A male common toad grasps a female with his front legs as part of the mating process. Common toads stay in amplexus for several days. As the female lays a long, double string of small black eggs, the male fertilises them with his sperm; the gelatinous egg strings, which may contain 3000 to 6000 eggs and be 3 to 4.5 metres (10 to 15 ft) in length, are later tangled in plant stalks.
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Image 12
Emerald-eyed tree frog
Photo: Paolo Costa Baldi
The emerald-eyed tree frog (Rana platanera) is a species of frog in the family Hylidae found in South America.
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Image 13
Eastern newt
Photo credit: Patrick Coin
A 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.
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Image 14
Dendrobates azureus
Photo: Quartl
Dendrobates azureus, commonly known as the blue poison dart frog or okopipi, is a poison dart frog found in the forests surrounded by the Sipaliwini Savanna in southern Suriname. Authorities have recently treated it as a variant of Dendrobates tinctorius rather than a distinct species as before.
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Image 15
Wallace's flying frog
Photograph credit: Rushenb
Wallace'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.
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Selected toad article

The European green toad (Bufotes viridis) is a species of true toad found in steppes, mountainous areas, semi-deserts, urban areas and other habitats in mainland Europe, ranging from far eastern France and Denmark to the Balkans, Western Russia and the Caucasus. As historically defined, the species ranged east through the Middle East and Central Asia to western China, Mongolia and northwestern India, and south through Italy and the Mediterranean islands to North Africa.

Following genetic and morphological reviews, 14 populations (all largely or entirely Asian, except for the African and Balearic green toads) are now regarded as separate species. These species and the European green toad are placed in their own genus Bufotes, but they were included in Bufo. (Full article...)

List of selected toad articles

Selected caecilian article

Gegeneophis ramaswamii, common names Tenmalai caecilian, Tenmalai blind caecilian, Ramaswami's caecilian, and forest caecilian is a species of caecilian. It is endemic to the southern portion of the Western Ghats, India, and is recorded from Kerala and Tamil Nadu. The specific name ramaswamii honours L. S. Ramaswami, an Indian herpetologist. (Full article...)