The Cryptobranchoidea are a

suborder Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized ...

salamanders Salamanders are a group of amphibians typically characterized by their 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. All t ...

found in Asia, European Russia, and the United States. They are known as primitive salamanders, in contrast to

Salamandroidea 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 Angu ...

, the advanced salamanders. It has two living subdivisions,

Cryptobranchidae The Cryptobranchidae (commonly known as giant salamanders) 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 ...

( Asian giant salamanders and hellbenders), and

Hynobiidae The Asiatic salamanders (family Hynobiidae) are primitive salamanders found all over Asia, and in European Russia. They are closely related to the giant salamanders (family Cryptobranchidae), with which they form the suborder Cryptobranchoidea. A ...

, commonly known as Asian salamanders. Giant salamanders are obligate paedomorphs with partial metamorphosis, but Asiatic salamander goes through a full metamorphosis. The only known exceptions are the

Longdong stream salamander The Longdong stream salamander (''Batrachuperus londongensis'') is a species of salamander in the family Hynobiidae endemic to Sichuan, China, where it is found in the Longdong River on Mount Emei. Its natural habitats are rivers and freshwater ...

, which has been documented as facultatively neotenic, and the Ezo salamander, where a now assumed extinct population from Lake Kuttarush in Hokkaido had neotenic traits like gills in adults. The oldest members of the group are known from the

Middle Jurassic The Middle Jurassic is the second Epoch (geology), epoch of the Jurassic Period (geology), Period. It lasted from about 174.1 to 161.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relativel ...

(

Bathonian In the geologic timescale the Bathonian is an age (geology), age and stage (stratigraphy), stage of the Middle Jurassic. It lasted from approximately 168.2 ±1.2 annum, Ma to around 165.3 ±1.1 Ma (million years ago). The Bathonian Age succeeds ...

) aged

Yanliao Biota The Yanliao Biota is the name given to an assembly of fossils preserved in northeastern China from the Middle to Late Jurassic.Xu, X., Zhou, Z., Sullivan, C. and Wang, Y., 2017. The Yanliao Biota: a trove of exceptionally preserved Middle-Late Ju ...

of China.

Taxonomy

This suborder contains only two families at present. All other members are extinct and are only known as fossils. *''

Chunerpeton ''Chunerpeton tianyiensis'' is an extinct species of salamander from the Late Jurassic Daohugou Beds in Ningcheng County, Nei Mongol (Inner Mongolia), China. It is the only species classified under the genus ''Chunerpeton'', which means "early ...

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. The formation consists of coarse conglomerates ...

, China, Middle Jurassic (

) (

neotenic Neoteny (), also called juvenilization,Montagu, A. (1989). Growing Young. Bergin & Garvey: CT. is the delaying or slowing of the physiological, or somatic, development of an organism, typically an animal. Neoteny in modern humans is more signif ...

) (Note that this taxon has alternatively been recovered outside of Cryptobranchoidea or even outside Urodela) *'' Jeholotriton'' Haifanggou Formation, China, Middle Jurassic (Bathonian) (neotenic) *''

Pangerpeton ''Pangerpeton'' is an extinct genus of salamanders. Its monotypic species is ''Pangerpeton sinensis''. ''Pangerpeton'' is a metamorphosed, primitive salamander from the Late Jurassic Daohugou fossil bed near Wubaiding Village of Lingyuan City, ...

'' Haifanggou Formation, China, Middle Jurassic (Bathonian) *''

Nesovtriton ''Nesovtriton'' is an extinct genus of cryptobranchoid salamander known from the Late Cretaceous (Turonian age) of Bissekty Formation, in Uzbekistan , image_flag = Flag of Uzbekistan.svg , image_coat = Emblem of Uzb ...

Bissekty Formation The Bissekty Formation (sometimes referred to as Bissekt) is a formation (geology), geologic formation and Lagerstätte which outcrop, crops out in the Kyzyl Kum desert of Uzbekistan, and dates to the Late Cretaceous Period (geology), Period. Laid ...

, Uzbekistan, Late Cretaceous (

Turonian The Turonian is, in the International Commission on Stratigraphy, ICS' geologic timescale, the second age (geology), age in the Late Cretaceous epoch (geology), Epoch, or a stage (stratigraphy), stage in the Upper Cretaceous series (stratigraphy), ...

) *''

Iridotriton ''Iridotriton'' is an extinct genus of salamander known from a fossil discovered in stratigraphic zone 6 of the late Jurassic Morrison Formation,Foster, J. (2007). "Appendix." ''Jurassic West: The Dinosaurs of the Morrison Formation and Their Wo ...

Morrison Formation The Morrison Formation is a distinctive sequence of Upper Jurassic sedimentary rock found in the western United States which has been the most fertile source of dinosaur fossils in North America. It is composed of mudstone, sandstone, siltston ...

, United States, Late Jurassic (

Tithonian In the geological timescale, the Tithonian is the latest age (geology), age of the Late Jurassic Epoch and the uppermost stage (stratigraphy), stage of the Upper Jurassic Series. It spans the time between 149.2 ±0.7 annum, Ma and 143.1 ±0.6 (mi ...

) *'' Kiyatriton''

Itat Formation The Itat Formation (Russian: итатская свита) is a geologic formation in western Siberia. It was deposited in the Bajocian to Bathonian ages of the Middle Jurassic. Dinosaur remains are among the fossils that have been recovered from ...

, Russia, Middle Jurassic (Bathonian)

Ilek Formation The Ilek Formation is a Lower Cretaceous geologic Formation (geology), formation in Western Siberia. Many different fossils have been recovered from the formation. It overlies the Late Jurassic Tyazhin Formation and underlies the Albian Kiya Form ...

, Russia, Early Cretaceous (

Barremian The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 125.77 Ma (million years ago) and 121.4 ± 1.0 Ma (Historically, this stage was placed at 129.4 million to approximately 125 million years ago) It is a ...

Aptian The Aptian is an age (geology), age in the geologic timescale or a stage (stratigraphy), stage in the stratigraphic column. It is a subdivision of the Early Cretaceous, Early or Lower Cretaceous epoch (geology), Epoch or series (stratigraphy), S ...

) (Presumed to be a cryptobranchoid) *'' Laccotriton'' Fengshan fossil bed, China, Late Jurassic (Tithonian) *''

Sinerpeton ''Sinerpeton'' is an extinct genus of salamander from the Late Jurassic of China. It is monotypic and consists of one species, ''S. fengshanense''. Discovery and naming ''Sinerpeton'' was recovered from Late Jurassic (Tithonian) fossil beds ...

'' Fengshan fossil bed, China, Late Jurassic (Tithonian) *

(Late Cretaceous-Recent) *Panhynobia ** ''

Liaoxitriton ''Liaoxitriton'' is an extinct genus of 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 Tiaoj ...

'' Jiufotang Formation, China, Early Cretaceous (Aptian) ** '' Linglongtriton''

Tiaojishan Formation The Tiaojishan Formation is a geological formation in Hebei and Liaoning, People's Republic of China, dating to the middle-late Jurassic period (Bathonian-Oxfordian (stage), Oxfordian stages). It is known for its Lagerstätte, exceptionally preser ...

, China, Late Jurassic ( Oxfordian) ** '' Neimengtriton'' Haifanggou Formation, China, Middle Jurassic (Bathonian) ** '' Regalerpeton''

Dabeigou Formation The Dabeigou Formation () is a palaeontological formation located in Hebei, China.Hauterivian The Hauterivian is, in the geologic timescale, an age in the Early Cretaceous Epoch or a stage in the Lower Cretaceous Series. It spans the time between 132.6 ± 2 Ma and 125.77 (million years ago). The Hauterivian is preceded by the Valangi ...

) ** '' Nuominerpeton''

Longjiang Formation Longjiang is the atonal pinyin romanization of various Chinese names, particularly or , meaning "DragonRiver". The same name also sometimes occurs as Lung Chiang, Keang, or Kiang. It may refer to: Places Rivers * Long River (Guangxi) * Long Riv ...

, China, Early Cretaceous (Aptian) **

(

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

-Recent)

References

Oxfordian first appearances Extant Late Jurassic first appearances Amphibian suborders Taxa named by Emmett Reid Dunn {{salamander-stub