# Cryobatrachus

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Extinct genus of temnospondyls

Cryobatrachus Temporal range: Early Triassic Life restoration of Cryobatrachus kitchingi Scientific classification Kingdom: Animalia Phylum: Chordata Clade: Tetrapoda Order: †Temnospondyli Suborder: †Stereospondyli Family: †Lydekkerinidae Genus: †Cryobatrachus Colbert and Cosgriff, 1974 Type species †Cryobatrachus kitchingi Colbert and Cosgriff, 1974

***Cryobatrachus*** (from [Greek](/source/Greek_language), [κρύος](https://en.wiktionary.org/wiki/%CE%BA%CF%81%CF%8D%CE%BF%CF%82) (krýos, "cold") and [βάτραχος](https://en.wiktionary.org/wiki/%CE%B2%CE%AC%CF%84%CF%81%CE%B1%CF%87%CE%BF%CF%82) (batrakhos, "frog")) is an extinct [genus](/source/Genus) of [temnospondyl](/source/Temnospondyl) amphibian from the [Early Triassic](/source/Early_Triassic) of Antarctica. The [type species](/source/Type_species) is *Cryobatrachus kitchingi*. It is known from a partial skull and an imprint of the [skull roof](/source/Skull_roof), both found in the [Fremouw Formation](/source/Fremouw_Formation) of the [Transantarctic Mountains](/source/Transantarctic_Mountains) at about 85° south latitude and described in 1974.[1] Many small bone fragments have also been identified, although they cannot be attributed with certainty to *C. kitchingi*. *Cryobatrachus* has been classified in the family [Lydekkerinidae](/source/Lydekkerinidae), as it is similar in appearance to the genus *[Lydekkerina](/source/Lydekkerina)* from South Africa.[\[a\]](#endnote_Anone) Because only a small number of features distinguish it from other lydekkerinids, *Cryobatrachus kitchingi* has more recently been considered a *[nomen dubium](/source/Nomen_dubium)*, meaning that its distinction from other better-known species may be unwarranted.[2]

## Discovery and specimens

[James Kitching](/source/James_Kitching), the discoverer of *Cryobatrachus* and the namesake of its type species, *C. kitchingi*

Fossils of *Cryobatrachus* were first found by South African paleontologist [James Kitching](/source/James_Kitching) in the [austral summer](/source/Austral_summer) of 1971–72 as part of an expedition headed by the Institute for Polar Studies at [Ohio State University](/source/Ohio_State_University), now known as the [Byrd Polar Research Center](/source/Byrd_Polar_Research_Center). Paleontologists [Edwin Harris Colbert](/source/Edwin_Harris_Colbert) of the [American Museum of Natural History](/source/American_Museum_of_Natural_History) and [John Cosgriff](https://en.wikipedia.org/w/index.php?title=John_Cosgriff&action=edit&redlink=1) of [Wayne State University](/source/Wayne_State_University) described these fossils in 1974, positing the new genus and species *Cryobatrachus kitchingi* with the specific name honoring Kitching. All specimens were uncovered from the lower part of the [Fremouw Formation](/source/Fremouw_Formation), which dates back to the Early Triassic. The [holotype](/source/Holotype) specimen, cataloged as [AMNH](/source/AMNH) 9503, is a partial skull with the ventral surface of the [dermal bones](/source/Dermal_bone) present. The [palate](/source/Palate) and [braincase](/source/Braincase) are not preserved. An additional [paratype](/source/Paratype) specimen called AMNH 9556 includes an impression of the skull roof, but no preserved bones. AMNH 9503 was found on [Kitching Ridge](/source/Kitching_Ridge) (which is also named after James Kitching) near [Shackleton Glacier](/source/Shackleton_Glacier), and AMNH 9556 was found on [Mount Kenyon](/source/Mount_Kenyon) near [McGregor Glacier](/source/McGregor_Glacier). Two crushed skulls from Kitching Ridge were also considered possible specimens of *Cryobatrachus*, as was part of an upper jaw from [Halfmoon Bluff](/source/Halfmoon_Bluff) (which is on the opposite side of Shackleton Glacier as Kitching Ridge). Colbert and Cosgriff tentatively attributed six smaller fragments from [Coalsack Bluff](/source/Coalsack_Bluff) to *Cryobatrachus*, including parts of lower jaw, the [clavicle](/source/Clavicle), and the [interclavicle](/source/Interclavicle). Fifteen other Coalsack Bluff fragments, attributed as possible remains of *Cryobatrachus* based on their small size alone, were described. These bones included parts of the legs, hips, vertebrae, and skull.[1] A 1977-78 expedition found a bone fragment on [Collinson Ridge](/source/Collinson_Ridge) and an interclavicle on [Shenk Peak](/source/Shenk_Peak) southeast of the paratype locality on Mount Kenyon, both of which were referred to *Cryobatrachus* in 1984.[3]

## Description

While most temnospondyls are characterized by features on the upper surface of the [skull roof](/source/Skull_roof) or the palate, only the underside of the skull roof is exposed in the holotype of *Cryobatrachus*. This part of the skull is not very well known in other temnospondyls, since it is normally hidden by the palate. The rock encasing the upper surface of the holotype skull was not removed because of time constraints during the 1971–72 expedition and fear that the specimen might be damaged.[1]

*Cryobatrachus* is most similar in appearance to the temnospondyl *Lydekkerina* from South Africa, and to several other temnospondyls in the family [Lydekkerinidae](/source/Lydekkerinidae) such as *[Limnoiketes](/source/Limnoiketes)*. In all of these temnospondyls, the eye sockets are closer to the tip of the snout than they are to the back of the skull. The skull of *Cryobatrachus* is about 4.5 centimetres (1.8 in) long, smaller than those of *Lydekkerina*, which are normally 7 to 8 centimetres (2.8 to 3.1 in) long. Unlike *Lydekkerina*, *Cryobatrachus* has a slightly oval-shaped skull that is widest near its middle rather than at the very back. The eye sockets are spaced closer together than they are in *Lydekkerina*. The [parietal foramen](/source/Pineal_foramen), a small hole at the top of the skull behind the eyes, is oval-shaped rather than circular as in most other temnospondyls. A space in the [squamosal bone](/source/Squamosal_bone) called the [otic notch](/source/Otic_notch) extends far into the skull, as in other lydekkerinids and a similar group of Triassic temnospondyls called [rhinesuchids](/source/Rhinesuchid). However, the notch in *Cryobatrachus* is unusual in that it is crescent- rather than oval-shaped and that it ends in a sharp point rather than a rounded margin. *Cryobatrachus* can be distinguished from another group of Triassic temnospondyls called [capitosaurians](/source/Capitosauria) in that its [quadratojugal](/source/Quadratojugal) bones (which make up the back of the upper jaws) end at the level of the [tabular horns](/source/Tabular_bone) (which project from the back of the skull roof). In most capitosaurians, the quadratojugals extend past the tabular horns.[1]

As is the case in other lydekkerinids, *Cryobatrachus* lacks the deep grooves on the skull that support a [lateral line](/source/Lateral_line) sensory system in other temnospondyls. The paratype specimen of *Cryobatrachus* shows that the upper surface of the skull was covered in small pits, with only a shallow groove running between the eye sockets. The lack of a lateral line system in *Cryobatrachus* and other lydekkerinids is usually taken as evidence that they spent most of their time on land, since lateral lines are typically only present in aquatic animals that use them to detect vibrations in water.

## Notes

1. [**^**](#ref_Anone) During the Early Triassic, Antarctica and South Africa were near one another as both were part of the landmass [Gondwana](/source/Gondwana).

## References

1. ^ [***a***](#cite_ref-CC74_1-0) [***b***](#cite_ref-CC74_1-1) [***c***](#cite_ref-CC74_1-2) [***d***](#cite_ref-CC74_1-3) Colbert, E.H.; Cosgriff, J.W. (1974). ["Labyrinthodont amphibians from Antarctica"](http://digitallibrary.amnh.org/dspace/handle/2246/2750). *American Museum Novitates* (2552): 1–30. [hdl](/source/Hdl_(identifier)):[2246/2750](https://hdl.handle.net/2246%2F2750).

1. **[^](#cite_ref-SM00_2-0)** Schoch, R. R.; Milner, A. R. (2000). "Stereospondyli". In P. Wellnhofer (ed.). *Handbuch der Paläoherpetologie*. Vol. 3B. Munich: Verlag Dr. Friedrich Pfeil. p. 203.

1. **[^](#cite_ref-CH84_3-0)** Cosgriff, J. W.; Hammer, W. R. (1984). "New material of labyrinthodont amphibians from the Lower Triassic Fremouw Formation of Antarctica". *Journal of Vertebrate Paleontology*. **4**: 47–56. [doi](/source/Doi_(identifier)):[10.1080/02724634.1984.10011985](https://doi.org/10.1080%2F02724634.1984.10011985).

- [Paleontology portal](https://en.wikipedia.org/wiki/Portal:Paleontology)

v t e Stereospondyli Kingdom: Animalia Phylum: Chordata Clade: Tetrapodomorpha Order: Temnospondyli Tetrapodomorpha see Tetrapodomorpha Temnospondyli see Temnospondyli Stereospondyli see below↓ Stereospondyli Stereospondyli Arachana Capulomala Peltobatrachus Lapillopsidae Lapillopsis Manubrantlia Rhigerpeton Rotaurisaurus Rhinesuchidae Australerpeton? Broomistega Laccosaurus Parapytanga? Rastosuchus Rhineceps Rhinesuchoides Rhinesuchus Uranocentrodon Lydekkerinidae Chomatobatrachus Cryobatrachus Deltacephalus Eolydekkerina Indobenthosuchus Luzocephalus? Lydekkerina Capitosauria Antarctosuchus Bukobaja Calmasuchus Capitosaurus Cherninia Cyclotosaurus Edingerella Eocyclotosaurus Eryosuchus Heptasaurus Huangfuchuansuchus Jammerbergia Kestrosaurus Kupferzellia Mastodonsaurus Meyerosuchus Odenwaldia Paracyclotosaurus Parotosuchus Quasicyclotosaurus Procyclotosaurus Promastodonsaurus Rhadalognathus Samarabatrachus Sassenisaurus Sclerothorax Selenocara Stanocephalosaurus Stenotosaurus Subcyclotosaurus Tatrasuchus Vladlenosaurus Volgasaurus Volgasuchus Warrenisuchus Watsonisuchus Wellesaurus Wetlugasaurus Xenotosuchus Yuanansuchus Trematosauria see below↓ Trematosauria Trematosauria Almasaurus Bothriceps Callistomordax Chinlestegophis Keratobrachyops Laidleria Latiscopus Qantas Rileymillerus Syrtosuchus Uruyiella Benthosuchidae Benthosuchus Kwatisuchus Trematosauridae Angusaurus Aphaneramma Cosgriffius Erythrobatrachus Gonioglyptus Hyperokynodon Icanosaurus Indolyrocephalus Inflectosaurus Lyrocephaliscus Microposaurus Panchetosaurus Platystega Prothoosuchus Stoschiosaurus Tertrema Tertremoides Thoosuchus Tirraturhinus Trematolestes Trematosuchoides Trematosaurus Trematosuchus Trematotegmen Wantzosaurus Metoposauridae Anaschisma Apachesaurus Arganasaurus Buettnererpeton Dutuitosaurus Metoposaurus Panthasaurus Rhytidosteidae Boreopelta Mahavisaurus Nanolania Peltostega Pneumatostega Rhytidosteus Sangaia Trucheosaurus Derwentiinae Arcadia Acerastia Deltasaurus Derwentia Indobrachyops Rewana Chigutisauridae Arenaerpeton Chigutisaurus Compsocerops Koolasuchus Pelorocephalus Siderops Brachyopidae Banksiops Bathignathus Batrachosaurus Batrachosuchoides Batrachosuchus Blinasaurus Brachyops Gobiops Hadrokkosaurus Notobrachyops Platycepsion Sinobrachyops Vanastega Vigilius Xenobrachyops Plagiosauridae Gerrothorax Megalophthalma Plagiobatrachus Plagiorophus Plagiosaurus Plagioscutum Plagiosternum Plagiosuchus See also: Trematosauroidea Metoposauroidea Rhytidosteoidea Brachyopomorpha Brachyopoidea Plagiosauroidea Category

Taxon identifiers Cryobatrachus Wikidata: Q5190509 GBIF: 4815953 IRMNG: 1031832 Open Tree of Life: 4133763 Paleobiology Database: 37075

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Adapted from the Wikipedia article [Cryobatrachus](https://en.wikipedia.org/wiki/Cryobatrachus) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Cryobatrachus?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.