Portal:Amphibians
The Amphibian Portal
Amphibians are ectothermic, anamniotic, four-limbed vertebrate animals that constitute the class Amphibia. They are 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 subclass Lissamphibia, with three living orders: Anura (frogs), 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.
The young generally undergo metamorphosis from larva with gills to an adult air-breathing form with lungs. Amphibians use their skin as a secondary respiratory surface 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 water bodies in which to breed. With their complex reproductive needs and permeable skins, amphibians are often ecological indicators; 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 sarcopterygian fish with lungs and bony-limbed fins, features that 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 (mammal predecessors). The origin of modern amphibians belonging to Lissamphibia, which first appeared during the Early Triassic, around 250 million years ago, has long been contentious. However the emerging consensus is that they likely originated from temnospondyls, the most diverse group of prehistoric amphibians, during the Permian period. (Full article...)
Selected frog article
The Hyperoliidae, or sedge frogs and bush frogs, are a large family of small to medium-sized, brightly colored frogs which contains more than 250 species in 19 genera. Seventeen genera are native to sub-Saharan Africa. In addition, the monotypic genus Tachycnemis occurs on the Seychelles Islands, and the genus Heterixalus (currently 10 species) is endemic to Madagascar.
Hyperoliids range from 1.5 to 8 cm (0.59 to 3.15 in) in body length. Many species have smooth, brightly patterned skin that almost looks enameled.
Most hyperoliids are arboreal, but some are terrestrial, including several Kassina species that move by walking or running rather than hopping. Diets vary widely, with examples including Paracassina, which specializes on snails, and Afrixalus fornasini, the only terrestrial frog known to prey on eggs of other species of anurans. (Full article...)Selected salamander article
List of selected salamander articles |
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Did you know? –
- ...that the Carrikeri Harlequin Frog, a critically endangered toad endemic to northern Colombia, was recently rediscovered after an absence of 14 years?
- ... that the male common midwife toad (pictured), like other members of the genus Alytes, carries his eggs around with him until they hatch?
- ... that the small frog Kurixalus idiootocus lays its eggs on the ground and they do not hatch until rain falls?
Selected amphibian type
Toad is a common name for certain frogs, especially of the family Bufonidae, that are characterized by dry, leathery skin, short legs, and large bumps covering the parotoid glands.
A distinction between frogs and toads is not made in scientific taxonomy, but is common in popular culture (folk taxonomy), in which toads are associated with drier, rougher skin and more terrestrial habitats. (Full article...)List of selected amphibian type articles |
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Selected images
Selected toad article
Selected caecilian article
The Ichthyophiidae are the family of Asiatic tailed caecilians or fish caecilians found in South and Southeast Asia as well as southernmost China.
They are primitive caecilians, lacking many of the derived characters found in the other families. For example, their mouths are not recessed underneath their heads, they possess tails, and they have numerous scales on their bodies. However, they have two sets of muscles for closing the jaw, a feature unique to caecilians, but absent in the related family Rhinatrematidae.
They lay their eggs in cavities in moist soil, where they hatch into larvae that seek out streams or underground seepages, before metamorphosing into adults. Some evidence indicates the females may protect their eggs until they hatch. (Full article...)Need help?
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