Portal:Amphibians

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, but 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 even 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.

Contrary to a common misconception, adult amphibians generally cannot breathe underwater. Wildlife hospitals report that a frequent mistake made by people who bring frogs and toads for treatment is placing them in water-filled aquaria without providing a means of exit. As a result, they may drown. (Full article...)

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

Did you know? –

... that the Mexican burrowing caecilian (pictured) is viviparous, with the young feeding on glandular secretions in the oviduct?
... that the red-cheeked salamander, which is distasteful to predators, is mimicked by the harmless imitator salamander?
... that the Black Salamander may defend itself by biting a western garter snake attacking it?
... that the Ouachita Dusky Salamander, the Fourche Mountain Salamander (pictured), and the Rich Mountain Salamander are all endemic to the Ouachita Mountains in Arkansas and Oklahoma?
...that the American toad is a common species of toad found throughout the eastern United States and Canada?

Selected amphibian type

Oscaecilia ochrocephala (Caeciliidae)

Caecilians (New Latin for 'blind ones', from caecus, blind) are a group of limbless, worm-shaped or snake-shaped amphibians, with either small eyes or no eyes, comprising the order Gymnophiona. They mostly live hidden in soil or in streambeds, making them some of the least familiar amphibians. Modern caecilians live in the tropics of South and Central America, Africa, and southern Asia. Caecilians feed on small subterranean creatures, such as earthworms. The body is noodle-like and often dark in colour, and the skull is bullet-shaped and strongly built. The caecilian head has several unique adaptations, such as fused skull and jaw bones, a two-part system of jaw muscles, and chemosensory tentacles between the eyes and nostrils. The skin is slimy, with ringlike markings or grooves, and in some species hides scales underneath.

Modern caecilians are a clade, the order Gymnophiona (or Apoda), one of the three living amphibian groups alongside Anura (frogs and toads) and Urodela (salamanders). Gymnophiona is a crown group, encompassing all modern caecilians and all descendants of their last common ancestor. There are more than 220 living species of caecilian classified in 10 families. Gymnophionomorpha is a recently coined name for the corresponding total group which includes Gymnophiona as well as a few extinct stem-group caecilians (extinct amphibians whose closest living relatives are caecilians but are not descended from any caecilian). Some palaeontologists have used the name Gymnophiona for the total group and the old name Apoda for the crown group. However, Apoda has other even older uses, including as the name of a genus of butterfly, making its use potentially confusing and best avoided. The clade's name 'Gymnophiona' comes from Ancient Greek γυμνος (gumnos), meaning "naked", and ὄφις (óphis), meaning "snake", as the caecilians were originally thought to be related to snakes and to lack scales.

The study of caecilian evolution is complicated by their poor fossil record and specialized anatomy. Genetic evidence and some anatomical details (such as pedicellate teeth) support the idea that frogs, salamanders, and caecilians (collectively known as lissamphibians) are each other's closest relatives. Frogs and salamanders show many similarities to dissorophoids, a group of extinct amphibians in the order Temnospondyli. Caecilians are more controversial; many studies extend dissorophoid ancestry to caecilians. Some studies have instead argued that caecilians descend from extinct lepospondyl or stereospondyl amphibians, contradicting evidence for lissamphibian monophyly (common ancestry). Rare fossils of early gymnophionans, such as Eocaecilia and Funcusvermis, have helped to test the various conflicting hypotheses for the relationships between caecilians and other living and extinct amphibians. (Full article...)

List of selected amphibian type articles

Selected images

Image 1
Edible frog
Photograph: Grand-Duc; edit: Niabot
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.
Image 2
Balearic green toad
Photograph: Richard Bartz
A female Balearic green toad (Bufo balearicus), a lowland species of toad native to Italy.
Image 3
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.
Image 4
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.
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.
Image 6
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.
Image 7
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.
Image 8
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.
Image 9
Atelopus limosus
Photograph: Brian Gratwicke
A female limosa harlequin frog (Atelopus limosus) in Panama. This endangered species of toad in the family Bufonidae inhabits stream banks in tropical moist lowland forests and rivers of the Chagres watershed. It is found in two colour forms, one in lowlands and one in uplands.
Image 10
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.
Image 11
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.
Image 12
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.
Image 13
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.
Image 14
Marsh frog
Photograph credit: Charles James Sharp
The marsh frog (Pelophylax ridibundus) is a species of amphibian native to Europe and parts of Asia. It is the largest type of frog in most of its range, growing to a snout-to-vent length of around 100 mm (4 in); tadpoles can reach up to 190 mm (7.5 in) in length, but this usually occurs in places with long winters where the tadpole has time to grow. Marsh frogs hibernate during the winter, either underwater or in burrows, and are able to use the Earth's magnetic field to locate breeding ponds. This marsh frog was photographed in Kampinos National Park, Poland.
Image 15
Red-eyed Tree Frog
Photo credit: LiquidGhoul
The Red-eyed Tree Frog (Litoria chloris) is a species of tree frog native to eastern Australia; ranging from north of Sydney to Proserpine in mid-northern Queensland. These frogs typically reach a size of 65 millimetres (2.6 in). Its skin secretions have been found to destroy HIV, without harming healthy T cells.

Selected toad article

Frostius pernambucensis males

Frostius – known as Frost's toads – is a small genus of true toads consisting of only two species endemic to Brazil. The genus was proposed by David C. Cannatella in 1986 based on an analysis of a species previously classified as Atelopus. Various morphological and life-history information first suggested that it is sister taxon to Atelopus or Atelopus + Osornophryne, but later molecular evidence suggests that it is sister taxon to Oreophrynella. It was named for Darrel Frost in recognition of his work on anuran systematics. (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...)