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. All extant (living) amphibians belong to the monophyletic 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. Their life cycle typically starts out as aquatic larvae with gills known as tadpoles, 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" 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 American bullfrog, often simply known as the bullfrog in Canada and the United States, is a large true frog native to eastern North America. It typically inhabits large permanent water bodies such as swamps, ponds, and lakes. Bullfrogs can also be found in manmade habitats such as pools, koi ponds, canals, ditches and culverts. The bullfrog gets its name from the sound the male makes during the breeding season, which sounds similar to a bull bellowing. The bullfrog is large and is commonly eaten throughout its range, especially in the southern United States where they are plentiful.
The spotted salamander or yellow-spotted salamander is a mole salamander common in eastern United States and Canada. It is the state amphibian of Ohio and South Carolina. The species ranges from Nova Scotia, to Lake Superior, to southern Georgia and Texas. Its embryos have been found to have symbiotic algae living in and around them, the only known example of vertebrate cells hosting an endosymbiont microbe.
The spring peeper is a small chorus frog widespread throughout the eastern United States and Canada. They prefer permanent ponds due to their advantage in avoiding predation; however, they are very adaptable with respect to the habitat they can live in. In northern regions, the frog is able to endure below freezing temperatures due to the capacity of their livers to exude and flush the bloodstream with a glucose cryoprotectant which acts both as an anti-freeze in their blood, and allows organs like the heart to enter into a state of protected dormancy. They are so called because of their chirping call that marks the beginning of spring. Crucifer is derived from the Latin root meaning "cross-bearing". This could be a reference to the cross-like pattern on the spring peeper's dorsal side.
Lithobates sylvaticus or Rana sylvatica, commonly known as the wood frog, is a frog species that has a broad distribution over North America, extending from the boreal forest of the north to the southern Appalachians, with several notable disjunct populations including lowland eastern North Carolina. The wood frog has garnered attention from biologists because of its freeze tolerance, relatively great degree of terrestrialism, interesting habitat associations, and relatively long-range movements.
The American toad is a common species of toad found throughout Canada and the eastern United States. It is divided into three subspecies: the eastern American toad, the dwarf American toad and the rare Hudson Bay toad. Recent taxonomic treatments place this species in the genus Anaxyrus instead of Bufo.
The Pacific tree frog, also known as the Pacific chorus frog, has a range spanning the Pacific Northwest, from Northern California, Oregon, and Washington to British Columbia in Canada and extreme southern Alaska. They live from sea level to more than 10,000 feet in many types of habitats, reproducing in aquatic settings. They occur in shades of greens or browns and can change colors over periods of hours and weeks.
Cope's gray treefrog is a species of treefrog found in the United States and Canada. It is almost indistinguishable from the gray treefrog, and shares much of its geographic range. Both species are variable in color, mottled gray to gray-green, resembling the bark of trees. These are treefrogs of woodland habitats, though they will sometimes travel into more open areas to reach a breeding pond. The only readily noticeable difference between the two species is the mating call — Cope's has a faster-paced and slightly higher-pitched call than D. versicolor. In addition, D. chrysoscelis is reported to be slightly smaller, more arboreal, and more tolerant of dry conditions than D. versicolor.
The boreal chorus frog is a species of chorus frog native to Canada from central Quebec to eastern British Columbia and north to the Northwest Territories and the southern portion of the Yukon. It occurs in the USA throughout Montana, northwestern Wisconsin, northeastern Arizona, northern New Mexico, and southwestern Utah.
The western chorus frog, also known as striped chorus frog, or midland chorus frog is a species of frog found in Canada and the United States.
The plains spadefoot toad is a species of American spadefoot toad which ranges from southwestern Canada, throughout the Great Plains of the western United States, and into northern Mexico. Like other species of spadefoot toads, they get their name from a spade-like projection on their hind legs which allows them to dig into sandy soils. Their name, in part, comes from their keratinized metatarsals, which are wide instead of "sickle shaped". The species name translates as buzzing leaf shaped. This refers to the species' distinguishing features; its buzzing mating call, and its leaf-shaped digging metatarsals. It was first described by Cope in 1863.
The crawfish frog is a medium-sized species of frog native to the prairies and grasslands of the central United States. It gets its name because it inhabits the burrows of crayfish for most of the year. They have defined golden or black circles all over their body.
Ambystoma talpoideum, the mole salamander, is a species of salamander found in much of the eastern and central United States, from Florida to Texas, north to Illinois, east to Kentucky, with isolated populations in Virginia and Indiana. Older sources often refer to this species as the tadpole salamander because some individuals remain in a neotenic state. This salamander lives among the leaf litter on the forest floor, migrating to ponds to breed.
Dryophytes gratiosus, commonly known as the barking tree frog, is a species of tree frog endemic to the south-eastern United States. Formerly known as Hyla gratiosa.
The Yosemite toad is a species of true toad in the family Bufonidae. Endemic to the Sierra Nevada of California, the species ranges from the Alpine County to Fresno County. Yosemite toads are only found in the montane to subalpine elevational zone of 1,950–3,445 m (6,398–11,302 ft) asl. The Yosemite toad is similar to the nearby western toad, but in many ways adapted to a high elevation lifestyle. It was initially described during the Grinnell Survey of California, by an undergraduate student of Joseph Grinnell named Charles Camp.
The Appalachianmountain chorus frog, formerly known as just the mountain chorus frog, is a species of frog in the family Hylidae. The species is endemic to the United States. The natural habitats of P. brachyphona are temperate forests, rivers, intermittent rivers, swamps, freshwater marshes, intermittent freshwater marshes, freshwater springs, ponds, open excavations, and canals and ditches. It is threatened by habitat loss.
Chiasmocleis ventrimaculata, also known as the dotted humming frog, is a species of frog in the family Microhylidae. It is found in Bolivia, Brazil, Colombia, Ecuador, and Peru. Its natural habitats are subtropical or tropical moist lowland forests, swamps, and intermittent freshwater marshes.
The blackbelly salamander is a species of salamander in the family Plethodontidae. It is endemic to the United States. Its natural habitats are rivers, intermittent rivers, and freshwater springs. It is threatened by habitat loss.
The Mississippi gopher frog, also known commonly as the dark gopher frog, the dusky gopher frog, and the St. Tammany gopher frog, is a critically endangered species of frog in the family Ranidae. The species is endemic to the southern United States. Its natural habitats are temperate coastal forests and intermittent freshwater marshes. This secretive frog is on average 3 in (8 cm) long, with a dark brown or black dorsal surface covered in warts. It is a federally listed endangered species of the United States.
