A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura. The oldest fossil "proto-frog" Triadobatrachus is known from the Early Triassic of Madagascar, but molecular clock dating suggests their split from other amphibians may extend further back to the Permian, 265 million years ago. Frogs are widely distributed, ranging from the tropics to subarctic regions, but the greatest concentration of species diversity is in tropical rainforest. Frogs account for around 88% of extant amphibian species. They are also one of the five most diverse vertebrate orders. Warty frog species tend to be called toads, but the distinction between frogs and toads is informal, not from taxonomy or evolutionary history.
The Lissamphibia is a group of tetrapods that includes all modern amphibians. Lissamphibians consist of three living groups: the Salientia, the Caudata, and the Gymnophiona.
A tadpole is the larval stage in the biological life cycle of an amphibian. Most tadpoles are fully aquatic, though some species of amphibians have tadpoles that are terrestrial. Tadpoles have some fish-like features that may not be found in adult amphibians such as a lateral line, gills and swimming tails. As they undergo metamorphosis, they start to develop functional lungs for breathing air, and the diet of tadpoles changes drastically.
Leiopelma is a genus of New Zealand primitive frogs, belonging to the suborder Archaeobatrachia. It is the only genus in the monotypic family Leiopelmatidae. The leiopelmatids' relatively basal form indicates they have an ancient lineage. While some taxonomists have suggested combining the North American frogs of the genus Ascaphus in the family Ascaphidae with the New Zealand frogs of the genus Leiopelma in the family Leiopelmatidae, the current consensus is that these two groups constitute two separate families. The three extant species of Leiopelmatidae are only found in New Zealand.
Bombinatoridae is a family of toads found in Eurasia. Species of the family have flattened bodies and some are highly toxic.
The Alytidae are a family of primitive frogs. Their common name is painted frogs or midwife toads. Most are endemic to Europe, but three species occur in northwest Africa, and a species formerly thought to be extinct is found in Israel.
Archaeobatrachia is a suborder of the order Anura containing various primitive frogs and toads. As the name suggests, these are the most primitive frogs. Many of the species show certain physiological characteristics which are not present in other frogs and toads, thus giving rise to this group. They are largely found in Eurasia, New Zealand, the Philippines, and Borneo, and are characteristically small. In addition, the family Ascaphidae is found in the Pacific Northwest and northern Rocky Mountains of the United States, and is only represented by two species. The taxon is considered paraphyletic.
The Mesobatrachia is a paraphyletic group of relatively primitive frogs. At the end of 2016, it contained 3 superfamilies, 6 families, 16 genera, and 244 species. Recognized as a group in 1993, the name is contrasted with the primitive Archaeobatrachia and the more diverse and advanced Neobatrachia.
Caeciliidae is the family of common caecilians. They are found in Central and South America. Like other caecilians, they superficially resemble worms or snakes.
The Pipidae are a family of primitive, tongueless frogs. There are 41 species in the family, found in tropical South America and sub-Saharan Africa.
The European spadefoot toads are a family of frogs, the Pelobatidae, with only one extant genus Pelobates, containing six species. They are native to Europe, the Mediterranean, northwestern Africa, and western Asia.
The saddleback toads (Brachycephalus) are a genus of tiny toads and frogs in the family Brachycephalidae in the order Anura, ranging from south Bahia to Santa Catarina in southeastern Brazil. The genus includes two main groups, the often brightly coloured pumpkin toadlets, and the overall brown and more frog-like flea frogs, which once were placed in their own genus Psyllophryne. Some pumpkin toadlets are toxic and their often bright colours are considered aposematic. At about 1 cm (0.4 in) or less in snout–to–vent length, the flea frogs are some of the smallest frogs in the world.
Adelophryne is a genus of frogs in the family Eleutherodactylidae. They are native to northern South America east of the Andes, known roughly from the area corresponding to the Guiana Shield, as well as to the coastal area of Bahia, Brazil. Whether the genus is truly distinct from Phyzelaphryne remains uncertain. Common name shield frogs has been proposed for this genus, although the stem flea frog is used for some species.
Amphibians of Australia are limited to members of the order Anura, commonly known as frogs. All Australian frogs are in the suborder Neobatrachia, also known as the modern frogs, which make up the largest proportion of extant frog species. About 230 of the 5,280 species of frog are native to Australia with 93% of them endemic. Compared with other continents, species diversity is low, and may be related to the climate of most of the Australian continent. There are two known invasive amphibians, the cane toad and the smooth newt.
Hyloidea is a superfamily of frogs. Hyloidea accounts for 54% of all living anuran species. The superfamily Hyloidea branched off from its closest relative, the Australobatrachia, during the mid-Cretaceous. The fossil evidence found during the Cretaceous-Paleogene extinction event could not determine the effects upon the frogs, due to the lack of fossils. Increased forestation erupted after this extinction, possibly leading to more arboreal adaptations of these anurans to be best suited for this habitat.
Australobatrachia is a clade of frogs in the suborder Neobatrachia. It comprises three families of frogs with a Gondwanan distribution, being known from Chile, Australia, and New Guinea. Together, they form the sister group to the superfamily Hyloidea.
Brachycephalus pulex, also known as the Brazilian flea toad and the Serra Bonita flea toad, is a species of small frogs in the family Brachycephalidae. It is one of more than 35 named species within the genus Brachycephalus. It has been suggested to represent the smallest known vertebrate, with an average snout–vent length of 7.10 millimetres (0.280 in) in mature males.
