Cryptobranchoidea

Cryptobranchoidea Temporal range: Middle Jurassic - Present Bathonian–Present PreꞒ Ꞓ O S D C P T J K Pg N
Cryptobranchus alleganiensis
Hynobius fossigenus
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Amphibia
Order:	Urodela
Suborder:	Cryptobranchoidea Dunn, 1922
Subgroups
† Chunerpeton ? † Jeholotriton † Pangerpeton † Nesovtriton ? † Iridotriton ? † Kiyatriton ? † Laccotriton † Sinerpeton Cryptobranchidae Panhynobia Ji, Anderson & Gao, 2021 † Liaoxitriton † Linglongtriton † Neimengtriton † Regalerpeton † Nuominerpeton Hynobiidae

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) (Note that this taxon has alternatively been recovered outside of Cryptobranchoidea ^[5] or even outside Urodela ^[6] )

• † 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 ^[4]
  • † 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)

References

1. Heying, Heather. "ADW:Family Cryptobranchidae: giant salamanders and hellbenders".
2. Bonett, Ronald M.; Blair, Andrea L. (2017). "Evidence for complex life cycle constraints on salamander body form diversification". Proceedings of the National Academy of Sciences. 114 (37): 9936–9941. Bibcode:2017PNAS..114.9936B. doi: 10.1073/pnas.1703877114 . PMC   5604006 .
3. Jiang, J. P.; Jia, J.; Zhang, M.; Gao, K. Q. (2018). "Osteology of Batrachuperus londongensis (Urodela, Hynobiidae): Study of bony anatomy of a facultatively neotenic salamander from Mount Emei, Sichuan Province, China". PeerJ. 6 e4517. doi: 10.7717/peerj.4517 . PMC   5878659 . PMID   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. 24 (7) 102744. Bibcode:2021iSci...24j2744J. doi: 10.1016/j.isci.2021.102744 . ISSN   2589-0042. PMC   8264161 . PMID   34278256.
5. Rong, Yu-Fen; Vasilyan, Davit; Dong, Li-Ping; Wang, Yuan (2020-12-08). "Revision of Chunerpeton tianyiense (Lissamphibia, Caudata): Is it a cryptobranchid salamander?". Palaeoworld. 30 (4): 708–723. doi: 10.1016/j.palwor.2020.12.001 . ISSN   1871-174X.
6. Jones, Marc E. H.; Benson, Roger B. J.; Skutschas, Pavel; Hill, Lucy; Panciroli, Elsa; Schmitt, Armin D.; Walsh, Stig A.; Evans, Susan E. (2022-07-11). "Middle Jurassic fossils document an early stage in salamander evolution". Proceedings of the National Academy of Sciences. 119 (30) e2114100119. Bibcode:2022PNAS..11914100J. doi: 10.1073/pnas.2114100119 . ISSN   0027-8424. PMC   9335269 . PMID   35858401.