Sirenidae, the sirens, are a family of neotenic aquatic salamanders. Family members have very small fore limbs and lack hind limbs altogether. In one species, the skeleton in their fore limbs is made of only cartilage. In contrast to most other salamanders, they have external gills bunched together on the neck in both larval and adult states. Sirens are found only in the Southeastern United States and northern Mexico.
Caecilians are a group of limbless, vermiform (worm-shaped) or serpentine (snake-shaped) amphibians. They mostly live hidden in soil or in streambeds, and this cryptic lifestyle renders caecilians among 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 cylindrical and often darkly coloured, and the skull is bullet-shaped and strongly built. Caecilian heads have several unique adaptations, including fused cranial and jaw bones, a two-part system of jaw muscles, and a chemosensory tentacle in front of the eye. The skin is slimy and bears ringlike markings or grooves, which may contain tiny scales.
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.
Rhinatrematidae is a family of caecilians, also known as the Neotropical tailed caecilians, American tailed caecilians. or beaked caecilians. They are found in the equatorial countries of South America.
Uraeotyphlus is a genus of caecilians in the family Ichthyophiidae. There are seven species in this genus, all of which are endemic to the Western Ghats of southwestern India. Previously, the genus has also been placed in its own monotypic family Uraeotyphlidae.
The Scolecomorphidae are a family of caecilians also known as tropical caecilians, buried-eyed caecilians, or African caecilians. They are found in Cameroon in West Africa, and Malawi and Tanzania in East Africa. Caecilians are legless amphibians which superficially resemble worms or snakes.
Caeciliidae is the family of common caecilians. They are found in Central and South America. Like other caecilians, they superficially resemble worms or snakes.
Typhlonectidae, also known as aquatic caecilians or rubber eels, are a family of caecilians found east of the Andes in South America.
Ichthyophis garoensis, the Garo Hills caecilian, is a species of caecilian found in Assam and Meghalaya in north-eastern India. The Husain's caecilian Ichthyophis husaini was until 2016 considered a separate species. It is a subterranean caecilian that lives in the moist leaf-litter of tropical forests. It is typically found close to streams and other waterbodies.
Uraeotyphlus interruptus, also known as the Chengalam caecilian, is a species of caecilian in the family Ichthyophiidae. It is endemic to the Western Ghats in southern India and is only known from its type locality, Chengalam village in Kerala.
Uraeotyphlus oxyurus, also known as the red caecilian, sharp-nosed caecilian, dark-brown caecilian, pale-throated caecilian, or harp-tailed caecilian, is a species of caecilian in the family Ichthyophiidae. It is endemic to the Western Ghats in Kerala and Tamil Nadu, southern India.
Schistometopum thomense is a species of amphibian in the family Dermophiidae, endemic to São Tomé and Ilhéu das Rolas. It is found in most soils on São Tomé, from tropical moist lowland forests to coastal coconut plantations. It is absent only from the driest northern areas of the island. It is typically around 30 cm (12 in) in length, and is often bright yellow. The size of S. thomense can vary throughout São Tomé, however, and it is the only known caecilian to follow Bergmann's rule, which states that a decreasing temperature due to factors such as increasing altitude will cause an increase in the body size of endothermic vertebrate species. The island of São Tomé is a massive shield volcano, and it therefore has differing altitudes throughout the island, potentially resulting in the size diversity of S. thomense. This species may be referred to as the São Tomé caecilian, as the Agua Ize caecilian, or as the island caecilian, or by the local name of cobra bobo.
Ichthyophis biangularis, the angular caecilian or Metang caecilian, is a species of amphibian in the family Ichthyophiidae endemic to Borneo (Malaysia): it is only known from its type locality, Mount Matang in Sarawak, where the holotype was collected in 1872 by Alfred Hart Everett. New specimens were collected from the type locality only in 2009. In addition, one larval sample was collected from the same region and identified as likely Ichthyophis biangularis using genetic methods.
The Koh Tao Island caecilian is a species of amphibian in the family Ichthyophiidae found in Cambodia, Laos, Myanmar, Thailand, and Vietnam. Also known as the Ichthyophis bannanicus, the Banna caecilian, it is also found in southern China.
Uraeotyphlus oommeni, sometimes known as the Oommen's caecilian, Oommen's Uraeotyphlus, or Bonnacord caecilian, is a species of caecilian in the family Ichthyophiidae. Within Uraeotyphlus, it belongs to the U. malabaricus group showing no obvious external differentiation between primary and higher-order annuli. This species is endemic to the Western Ghats and only known from its type locality, Bonaccord, Thiruvananthapuram district, southern Kerala. Very little is known about this species known only from a single specimen collected from an imprecise location.
The Siphonopidae are the family of common caecilians. They are found in Central and South America. Like other caecilians, they superficially resemble worms or snakes.
