Cryptobranchoidea Explained

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.^[1] It has two living subdivisions, Cryptobranchidae (Asian giant salamanders and hellbenders), and Hynobiidae, commonly known as Asian salamanders.

Giant salamanders are obligate paedomorphs with partial metamorphosis,^[2] but Asiatic salamander goes through a full metamorphosis. The only known exceptions are the Longdong stream salamander, 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.^[3]

The oldest members of the group are known from the Middle Jurassic (Bathonian) aged Yanliao Biota of China.^[4]

Taxonomy

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

• Chunerpeton Haifanggou Formation, China, Middle Jurassic (Bathonian) (neotenic, has alternatively been recovered outside of Cryptobranchoidea)^[5]
• Jeholotriton Haifanggou Formation, China, Middle Jurassic (Bathonian) (neotenic)
• Pangerpeton Haifanggou Formation, China, Middle Jurassic (Bathonian)
• Nesovtriton Bissekty Formation, Uzbekistan, Late Cretaceous (Turonian)
• Iridotriton Morrison Formation, United States, Late Jurassic (Tithonian)
• Kiyatriton Itat Formation, Russia, Middle Jurassic (Bathonian) Ilek Formation, Russia, Early Cretaceous (Barremian-Aptian) (Presumed to be a cryptobranchoid)
• Laccotriton Fengshan fossil bed, China, Late Jurassic (Tithonian)
• Sinerpeton Fengshan fossil bed, China, Late Jurassic (Tithonian)
• Cryptobranchidae (Late Cretaceous-Recent)
• Panhynobia
  • Liaoxitriton Jiufotang Formation, China, Early Cretaceous (Aptian)
  • Linglongtriton Tiaojishan Formation, China, Late Jurassic (Oxfordian)
  • Neimengtriton Haifanggou Formation, China, Middle Jurassic (Bathonian)
  • Regalerpeton Dabeigou Formation, China, Early Cretaceous (Hauterivian)
  • Nuominerpeton Longjiang Formation, China, Early Cretaceous (Aptian)
  • Hynobiidae (Miocene-Recent)

Notes and References

1. Web site: ADW:Family Cryptobranchidae: giant salamanders and hellbenders. Heather. Heying.
2. 10.1073/pnas.1703877114 . Evidence for complex life cycle constraints on salamander body form diversification . 2017 . Bonett . Ronald M. . Blair . Andrea L. . Proceedings of the National Academy of Sciences . 114 . 37 . 9936–9941 . free . 2017PNAS..114.9936B . 5604006 .
3. 5878659 . 2018 . Jiang . J. P. . Jia . J. . Zhang . M. . Gao . K. Q. . Osteology of Batrachuperus londongensis (Urodela, Hynobiidae): Study of bony anatomy of a facultatively neotenic salamander from Mount Emei, Sichuan Province, China . PeerJ . 6 . e4517 . 10.7717/peerj.4517 . free . 29610705 .
4. Jia. Jia. Anderson. Jason S.. Gao. Ke-Qin. 2021-07-23. Middle Jurassic stem hynobiids from China shed light on the evolution of basal salamanders. iScience. English. 24. 7. 102744 . 10.1016/j.isci.2021.102744. 34278256 . 8264161 . 2589-0042. free. 2021iSci...24j2744J .
5. 2020-12-08. Revision of Chunerpeton tianyiense (Lissamphibia, Caudata): Is it a cryptobranchid salamander?. Palaeoworld. en. 10.1016/j.palwor.2020.12.001. 1871-174X. free. Rong . Yu-Fen . Vasilyan . Davit . Dong . Li-Ping . Wang . Yuan . 30 . 4 . 708–723 .