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 lepospondys. A fourth group of lissamphibians, the Albanerpetontidae, became extinct around 2 million years ago. (Full article...)

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Selected frog article

Hylodes meridionalis

Hylodidae, commonly known as giant Neotropical torrent frogs, is a family of frogs native to Brazil and northern Argentina. Phylogenetic evidence suggests the Hylodidae being the sister group to the Alsodidae.

Megaelosia goeldii is one species that lost the ability to produce vocalizations which in turn is denoted as mute. Through observation of aggressive interactions, it was found that the species' vocal sacs are used for one form of its visual signaling and communication. (Full article...)

List of selected frog articles

Selected salamander article

The greater siren (Siren lacertina) is an amphibian and one of the three members of the genus Siren. The largest of the sirens and one of the largest amphibians in North America, the greater siren resides in the coastal plains of the southeastern United States. (Full article...)

List of selected salamander articles
Caudata Ambystomatidae Cryptobranchoidea 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
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 2
Phantasmal poison frog
Photograph: H. Krisp
The 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.
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Image 3
Eastern Banjo Frog
Photo credit: Fir0002
The 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.
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Image 4
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 5
Epirus water frog
Photograph: Benny Trapp
The 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.
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Image 6
Mantella baroni
Photograph credit: Charles J. Sharp
Mantella baroni, commonly known as Baron's mantella, variegated golden frog or Madagascar poison frog, is a species of frog in the family Mantellidae. It is native to Madagascar and is seen here in Ranomafana National Park in the southeastern part of the country. The species was described in 1888 by George Albert Boulenger, who named it after its collector, Richard Baron. It has been classified as a least-concern species by the International Union for Conservation of Nature due to its relatively wide distribution, but is threatened by habitat loss. The frog's diet includes mites, which cause it to accumulate a high alkaloid concentration in its skin, making it toxic. The bright colours may serve as a warning sign to potential predators of the frog's toxicity.
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Image 7
White's Tree Frog
Photo credit: liquidGhoul
Native to Australia, White's Tree Frog grows up to 10 centimetres in length and is a popular household pet. In captivity, they have an average lifespan of 16 years. Its skin secretions contain caerins, a group of peptides with antibacterial and antiviral properties. Other peptides have been found to destroy HIV without harming healthy T-cells.
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Image 8
Dendropsophus microcephalus
Photo: Brian Gratwicke
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.
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Image 9
Golden toad
Photo: Charles H. Smith, USFWS
The 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.
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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
White's Tree Frog
Illustration credit: Ernst Haeckel
A 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.
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Image 12
Agile frog
Photograph credit: Petar Milošević
The agile frog (Rana dalmatina) is a species of true frog in the family Ranidae. Native to central and southern Europe, its brownish dappled colouring helps to conceal it among the leaf litter on the forest floor. This frog, about 5 cm (2.0 in) long, was photographed in the Golovec Forest in Slovenia.
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Image 13
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 14
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 15
Common Indian Toad
Photo: Lokionly
The Common Indian Toad (Duttaphrynus melanostictus) is native to South Asia. It grows to about 20 cm (8 in) long and breeds during monsoon season. These toads are often seen at night under street lamps especially during times when winged termites swarm. They have been noted to feed on a wide range of invertebrates, including scorpions.
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Selected toad article

Nectophrynoides wendyae, also known as the Uzungwe Scarp tree toad or Wendy's forest toad, is a terrestrial toad in the family Bufonidae. It is endemic to Tanzania and is only known from a single valley in the Udzungwa Mountains. The specific name wendyae honours Wendy Clarke, the describer's wife. (Full article...)

List of selected toad articles

Selected caecilian article

Oscaecilia ochrocephala

Oscaecilia is a genus of caecilians in the family Caeciliidae. The genus is distributed in southeastern Central America (Costa Rica, Panama) and northern South America, possibly extending into southern Brazil. They are sometimes known as the South American caecilians. (Full article...)

List of selected caecilian articles