The Cryptobranchidae are a family of large salamanders that are fully aquatic. The family includes some of the largest living amphibians. They are native to China, Japan, and the eastern United States. Giant salamanders constitute one of two living families—the other being the Asiatic salamanders belonging to the family Hynobiidae—within the Cryptobranchoidea, one of two main divisions of living salamanders.
The Caudata are a group of amphibians containing the extant salamanders and all extinct species of amphibians more closely related to salamanders than to frogs. They are typically characterized by a superficially lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults.
The Asiatic salamanders are primitive salamanders found all over Asia, and in European Russia. They are closely related to the giant salamanders, with which they form the suborder Cryptobranchoidea. About half of hynobiids currently described are endemic to Japan, but their range also covers parts of china, Russia, Afghanistan and iran.
The Salamandroidea are a suborder of salamanders, referred to as advanced salamanders. The members of the suborder are found worldwide except for Antarctica, sub-Saharan Africa, and Oceania. They differ from suborder Cryptobranchoidea as the angular and prearticular bones in their lower jaws are fused, their trunk ribs are bicapitate, and all members use internal fertilization. The female is fertilized by means of a spermatophore, a sperm-containing cap placed by the male in her cloaca. The sperm is stored in spermathecae on the roof of the cloaca until it is needed at the time of oviposition.
The Cryptobranchoidea are a suborder of salamanders found in Asia, European Russia, and the United States. They are known as primitive salamanders, in contrast to Salamandroidea, the advanced salamanders. It has two living subdivisions, Cryptobranchidae, and Hynobiidae, commonly known as Asian salamanders.
Chunerpeton tianyiensis is an extinct species of salamander from the Late Jurassic Daohugou Beds in Ningcheng County, Nei Mongol, China. It is the only species classified under the genus Chunerpeton, which means "early creeping animal". It was a small animal measuring 18 cm in length. It was neotenic, with the retention of external gills into adulthood. In the original description it was placed in Cryptobranchidae, which contains modern giant salamanders. A redescription published in 2020 found it to be a stem-group caudatan outside the crown group of modern salamanders. A 2021 study found it to be a member of Cryptobranchoidea outside of Cryptobranchidae. In 2022 a more extensive analysis, with greater character and taxon sampling, recovered Chunerpeton tianyiense as a stem-group caudatan, outside the crown group of modern salamanders, and associated with Beiyanerpeton jianpingensis and Qinglongtriton gangouensis.
Comonecturoides is an extinct genus of prehistoric caudate amphibians, possibly a salamander, from Reed's Quarry 9 of the Morrison Formation, near Como Bluff, Wyoming; the type species is C. marshi. It is considered a nomen dubium because the name is based on non-distinctive remains which cannot be classified in detail.
Hylaeobatrachus is an extinct genus of prehistoric salamander, known from the Early Cretaceous of Europe. The type species H. croyii is known from the Sainte-Barbe Clays Formation at the Iguanodon locality of Belgium, and was described by Louis Dollo. An unnamed Hylaeobatrachus-like taxon has also been reported from Las Hoyas, Spain. Both localities are of Barremian age. Hylaeobatrachus belongs to the crown group of modern salamanders, though its exact relationship with modern salamander groups is uncertain. It was neotenic, llike some modern salamanders.
Liaoxitriton is an extinct genus of prehistoric cryptobranchoid salamanders from the Early Cretaceous of China. It contains one species, L. zhongjiani, from the Aptian aged Yixian Formation. A second species, L. daohugouensis from the Middle/Late Jurassic Tiaojishan Formation, was moved to the genus Neimengtriton in 2021 after a number of studies noted morphological differences between the two genera.
Rhadinosteus parvus is an extinct species of prehistoric frogs that lived during the Late Jurassic. Fossils of the species were found at the Rainbow Park site in Utah's Dinosaur National Monument, from several slabs of rock which contain multiple partial specimens, from sediments belonging to the Morrison Formation. R. parvus was likely a member of Pipoidea and may have been a member of the family Rhinophrynidae.
Pangerpeton is an extinct genus of salamanders. Its monotypic species is Pangerpeton sinensis.
Sinerpeton is an extinct genus of salamander from the Late Jurassic of China. It is monotypic and consists of one species, S. fengshanense.
The Morrison Formation is a distinctive sequence of Late Jurassic sedimentary rock that is found in the western United States, which has a wide assortment of taxa represented in its fossil record, including dinosaur fossils in North America. It is composed of mudstone, sandstone, siltstone and limestone and is light grey, greenish gray, or red. Most of the fossils occur in the green siltstone beds and lower sandstones, relics of the rivers and floodplains of the Jurassic period.
The Tiaojishan Formation is a geological formation in Hebei and Liaoning, People's Republic of China, dating to the middle-late Jurassic period. It is known for its exceptionally preserved fossils, including those of plants, insects and vertebrates. It is made up mainly of pyroclastic rock interspersed with basic volcanic and sedimentary rocks. Previously, the Tiaojishan Formation was grouped together with the underlying Haifanggou Formation as a single "Lanqi Formation." The Tiaojishan Formation forms a key part of the Yanliao Biota assemblage, alongside the Haifanggou Formation.
The Haifanggou Formation, also known as the Jiulongshan Formation, is a fossil-bearing rock deposit located near Daohugou village of Ningcheng County, in Inner Mongolia, northeastern China.
Eobatrachus is a dubious genus of extinct frog known only from the holotype, YPM 1862, part of the right humerus, found in Reed's Quarry 9 near Como Bluff, Wyoming in the Late Jurassic-aged Morrison Formation. The type, and only species, E. agilis, was named by Othniel Charles Marsh in 1887 and he initially interpreted it as a mammal, although it was later re-classified as a genus of frog related to Comobatrachus and Eobatrachus is now seen as a dubious amphibian genus, possibly belonging to Anura (frogs) according to Foster (2007).
Beiyanerpeton is an extinct genus of salamandroid amphibians known from the Late Jurassic of western Liaoning Province, China. It contains a single species, B. jianpingensis. Alternative analyses suggest that B. jianpingensis is a stem salamander and not a salamandroid.
