Amphibians are ectothermic, tetrapod vertebrates of the class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terrestrial, fossorial, arboreal or freshwater aquatic ecosystems. Thus amphibians typically start out as larvae living in water, but some species have developed behavioural adaptations to bypass this.
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" appeared in the early Triassic of Madagascar, but molecular clock dating suggests their origins 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. There are about 7,300 recorded species, which 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.
Birth is the act or process of bearing or bringing forth offspring, also referred to in technical contexts as parturition. In mammals, the process is initiated by hormones which cause the muscular walls of the uterus to contract, expelling the fetus at a developmental stage when it is ready to feed and breathe.
A tadpole is the larval stage in the life cycle of an amphibian. Most tadpoles are fully aquatic, though some species of amphibians have tadpoles that are terrestrial. Tadpoles have some features that may not be found in adult amphibians such as a lateral line, gills, and tails. As they undergo metamorphosis, the diet of tadpoles changes and they will start to breathe air.
Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a term used as a "bridging" form of reproduction between egg-laying oviparous and live-bearing viviparous reproduction. Ovoviviparous animals possess embryos that develop inside eggs that remain in the mother's body until they are ready to hatch.
Internal fertilization is the union of an egg and sperm cell during sexual reproduction inside the female body. Internal fertilization, unlike its counterpart, external fertilization, brings more control to the female with reproduction. For internal fertilization to happen there needs to be a method for the male to introduce the sperm into the female's reproductive tract.
External fertilization is a mode of reproduction in which a male organism's sperm fertilizes a female organism's egg outside of the female's body. It is contrasted with internal fertilization, in which sperm are introduced via insemination and then combine with an egg inside the body of a female organism. External fertilization typically occurs in water or a moist area to facilitate the movement of sperm to the egg. The release of eggs and sperm into the water is known as spawning. In motile species, spawning females often travel to a suitable location to release their eggs. However, sessile species are less able to move to spawning locations and must release gametes locally. Among vertebrates, external fertilization is most common in amphibians and fish. Invertebrates utilizing external fertilization are mostly benthic, sessile, or both, including animals such as coral, sea anemones, and tube-dwelling polychaetes. Benthic marine plants also use external fertilization to reproduce. Environmental factors and timing are key challenges to the success of external fertilization. While in the water, the male and female must both release gametes at similar times in order to fertilize the egg. Gametes spawned into the water may also be washed away, eaten, or damaged by external factors.
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.
Spea hammondii, also known as the western spadefoot, western spadefoot toad, Hammond's spadefoot, or Hammond's spadefoot toad, is a species of amphibian in the family Scaphiopodidae. It is found in western California (USA) and northwestern Baja California (Mexico). The specific name hammondii is in honor of physician and naturalist William Alexander Hammond.
A true toad is any member of the family Bufonidae, in the order Anura. This is the only family of anurans in which all members are known as toads, although some may be called frogs. The bufonids now comprise more than 35 genera, Bufo being the best known.
Limnonectes is a genus of fork-tongued frogs of about 75 known species, but new ones are still being described occasionally. They are collectively known as fanged frogs because they tend to have unusually large teeth, which are small or absent in other frogs.
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.
Altiphrynoides is a genus of toads, commonly referred to as Ethiopian toads. They are restricted to highlands of south-central Ethiopia in the Arussi, Bale and Sidamo Provinces. Both species are threatened by habitat loss. They were formerly included in Nectophrynoides, but lack the unusual reproductive mode of those species. Conversely, some authorities treat Altiphrynoides as a monotypic genus for A. malcolmi, placing A. osgoodi in another monotypic genus, Spinophrynoides.
Parker's tree toad is a species of toad in the family Bufonidae. It is the single species in the genus Laurentophryne, and is endemic to Kivu region in the Democratic Republic of the Congo. Its natural habitat is subtropical or tropical moist montane forests. It is threatened by habitat loss. To describe their features, they have a straight head and pointed snout that goes further than its mouth. They have dorsal skin granular with multiple warts around their body more or less arranged in rows starting from the snout and moves to the shoulders and beyond; warts depicting a clear X on their backs typically colored grey or grey-whiteish.
Nectophrynoides minutus is a species of toad in the family Bufonidae. It is endemic to Tanzania and is known from the Uluguru and Rubeho Mountains. Common names small viviparous toad, minute tree toad, and dwarf forest toad have been proposed for it.
Nectophrynoides tornieri, Tornier's forest toad or kijula, is a species of toad in the family Bufonidae. It is endemic to Tanzania. This species was first described by Jean Roux in 1906 and was named in honour of the German zoologist Gustav Tornier.
Nectophrynoides laticeps is a species of toad in the family Bufonidae. It is endemic to the Ukaguru Mountains of Tanzania. Common name wide-headed viviparous toad has been proposed for it.
Nimbaphrynoides is a monotypic genus of true toads from highlands in the Mount Nimba region of the West African countries of Guinea, Liberia, and Côte d'Ivoire. The sole species is Nimbaphrynoides occidentalis. Along with Nectophrynoides, Eleutherodactylus jasperi, and Limnonectes larvaepartus, Nimbaphrynoides is one of the only anurans that combine internal fertilization with ovoviparity.
The Brazilian gold frog, also known as Izecksohn's toad or flea-frog, is a very small species of frogs in the family Brachycephalidae. It is endemic to southeastern Brazil and is known from the central part of the state of Rio de Janeiro and from Serra das Torres in extreme southern Espírito Santo.
Limnonectes larvaepartus is a species of fanged frog in the family Dicroglossidae endemic to northern and western Sulawesi, Indonesia. It is unique in that it has internal fertilization and gives live birth to tadpoles. Other frog species that have live birth produce froglets.
