# Cyclotosaurus

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Extinct genus of temnospondyls

This article is currently slated for merging. There is consensus to merge Cyclotosaurus buechneri into this article. You can carry out the merge by following the resolution at the AfD discussion and the merging instructions. (April 2026) Do not remove this notice until the merge is carried out.

Cyclotosaurus Temporal range: Middle Triassic–Late Triassic PreꞒ Ꞓ O S D C P T J K Pg N C. robustus skull, Museum of Paleontology, Tuebingen Scientific classification Kingdom: Animalia Phylum: Chordata Clade: Tetrapoda Order: †Temnospondyli Suborder: †Stereospondyli Clade: †Capitosauria Family: †Mastodonsauridae Genus: †Cyclotosaurus Fraas, 1889 Type species †Cyclotosaurus robustus (Meyer & Plienninger, 1844) Other species †C. mordax Fraas, 1913 †C. posthumus Fraas, 1913 †C. ebrachensis Kuhn, 1932 †C. hemprichi Kuhn, 1942 †C. intermedius Sulej & Majer, 2005 †C. buechneri Witzmann, Sachs & Nyhuis, 2016 †C.? papilio Wepfer [de], 1923 †C. naraserluki Marzola et al., 2017 Synonyms Mastodonsaurus robustus Meyer & Plienninger, 1844

***Cyclotosaurus*** is an extinct [genus](/source/Genus) of [temnospondyl](/source/Temnospondyl) within the [family](/source/Family_(taxonomy)) [Mastodonsauridae](/source/Mastodonsauridae). It was of large size for an [amphibian](/source/Amphibian), having a skull length of about 56 cm (22 in).[1][2]

## History

*Cyclotosaurus mordax* skull

German naturalist [Eberhard Fraas](/source/Eberhard_Fraas) erected the genus *Cyclotosaurus* in 1889, with *C. robustus* (previously *Mastodonsaurus robustus*) as the [type species](/source/Type_species).[3] Several species are known, mainly from Germany and Poland in Central Europe, as well as East Greenland and Thailand.[4][5] The relationships between species is unclear.[1]

The name means "round eared lizard" in [Ancient Greek](/source/Ancient_Greek), derived from round openings or fenestrae in the cheeks, which are thought to contain structures of the middle ear.[6]

*"Labyrinthodon" pachygnathus* Owen, 1842 and *"L." leptognathus* Owen, 1842 were transferred to *Cyclotosaurus*, as *C. pachygnathus* and *C. leptognathus*, by Paton (1974).[7] However, Damiani (2001) assigned the two species to Mastodonsauroidea indeterminate and Stereospondyli indeterminate.[3]

### Species

*C. intermedius* model

The genus is known from the [Ladinian](/source/Ladinian) in the [Middle Triassic](/source/Middle_Triassic) to the [Norian](/source/Norian) in the [Late Triassic](/source/Late_Triassic), and represents the last of the mastodonsaurids.[3]

The oldest, questionable, species is *Cyclotosaurus papilio*, known from a partial skull recovered from the Ladinian (Middle Triassic) age Upper [Muschelkalk](/source/Muschelkalk) beds from [Baden-Württemberg](/source/Baden-W%C3%BCrttemberg) in Germany.[3] *Cyclotosaurus robustus* is known from the [Carnian](/source/Carnian) ([Late Triassic](/source/Late_Triassic)) [Schilfsandstein Formation](/source/Schilfsandstein_Formation) in [Stuttgart-Feuerbach](/source/Stuttgart-Feuerbach) in Germany, while *C. ebrachensis* has been described from the [Blasensandstein Formation](https://en.wikipedia.org/w/index.php?title=Blasensandstein_Formation&action=edit&redlink=1) in [Ebrach](/source/Ebrach).[8] *Cyclotosaurus intermedius* has been described from lacustrine deposits dated to the late [Carnian](/source/Carnian) in [Krasiejów](/source/Krasiej%C3%B3w) in southern Poland. It is so named as it has features intermediate between the more ancient *C. robustus* and more recent *C. mordax*. Importantly, postcranial material of this species has been recovered, which is unusual this genus.[1] *Cyclotosaurus hemprichi* is known from the [Norian](/source/Norian) (Late Triassic) age Knollenmergel of Halberstadt, and *Cyclotosaurus posthumus* from the [Stubensandstein](/source/Stubensandstein) (Norian) in [Pfaffenhofen](/source/Pfaffenhofen_(district)).[8] A partial skull very similar to *C. posthumus* has been recovered from the Norian (Late Triassic) Huai Hin Lat Formation near [Chulabhorn Dam](/source/Chulabhorn_Dam) in Northeastern Thailand.[5] In 2016 a new species, *[C. buechneri](/source/Cyclotosaurus_buechneri)*, was described from the [Late Triassic](/source/Late_Triassic) (middle [Carnian](/source/Carnian)) [Stuttgart Formation](/source/Stuttgart_Formation) of [Bielefeld](/source/Bielefeld), the northernmost record in Germany.[9] In 2017, *Cyclotosaurus naraserluki*, a new endemic species from the [Fleming Fjord Fm.](/source/Fleming_Fjord_Formation), East Greenland, was described as the closest *Cyclotosaurus* species to *C. mordax*, also being the westernmost and northernmost known species of *Cyclotosaurus*.[2] In 2019 a *Cyclotosaurus* humerus was reported from a Rhaetian aged bone bed within Bonenburg clay pit in eastern [North Rhine-Westphalia](/source/North_Rhine-Westphalia), Germany. This represents the only definitive non-[brachyopoid](/source/Brachyopoidea) Rhaetian temnospondyl, and the last known record of [Capitosauria](/source/Capitosauria).[10]

## Phylogeny

*C. buechneri* skull

[Life restoration](/source/Life_restoration)

The phylogeny of [Capitosauroidea](/source/Capitosauroidea) according to Witzmann *et al.* (2016).[9]

Capitosauroidea Eryosuchus Kupferzellia Procyclotosaurus Paracyclotosaurus Mastodonsaurus Mastodonsaurus cappelensis Mastodonsaurus giganteus Cyclotosaurus Quasicyclotosaurus Eocyclotosaurus

The phylogeny of the genus *Cyclotosaurus* according to Witzmann et al. (2016).[9]

Cyclotosaurus C. robustus C. buechneri C. mordax C. ebrachensis C. intermedius C. posthumus C. hemprichi

See also alternative phylogenies from 2017[2] with the description of *C. naraserluki.*

## Palaeoecology

*Cyclotosaurus* are thought to have been semi-aquatic carnivores, though feeding strategies likely differed between species.[1]

## References

1. ^ [***a***](#cite_ref-sulej05_1-0) [***b***](#cite_ref-sulej05_1-1) [***c***](#cite_ref-sulej05_1-2) [***d***](#cite_ref-sulej05_1-3) Sulej, T.; Majer, D. (2005). ["The temnospondyl amphibian *Cyclotosaurus* from the Upper Triassic of Poland"](http://www.paleo.pan.pl/people/Sulej/publications/Sulej_Palaeontology_2005.pdf) (PDF). *Palaeontology*. **48**: 157–70. [doi](/source/Doi_(identifier)):[10.1111/j.1475-4983.2004.00430.x](https://doi.org/10.1111%2Fj.1475-4983.2004.00430.x).

1. ^ [***a***](#cite_ref-Marzola,_M._2017_2-0) [***b***](#cite_ref-Marzola,_M._2017_2-1) [***c***](#cite_ref-Marzola,_M._2017_2-2) Marzola, M., Mateus O., Shubin N. H., & Clemmensen L. B. (2017). Cyclotosaurus naraserluki, sp. nov., a new Late Triassic cyclotosaurid (Amphibia, Temnospondyli) from the Fleming Fjord Formation of the Jameson Land Basin (East Greenland). Journal of Vertebrate Paleontology. e1303501., 2017

1. ^ [***a***](#cite_ref-damiani_3-0) [***b***](#cite_ref-damiani_3-1) [***c***](#cite_ref-damiani_3-2) [***d***](#cite_ref-damiani_3-3) Damiani, Ross J. (2001). ["A systematic revision and phylogenetic analysis of Triassic mastodonsauroids (Temnospondyli: Stereospondyli)"](https://doi.org/10.1111%2Fj.1096-3642.2001.tb00635.x). *Zoological Journal of the Linnean Society*. **133** (4): 379–482. [doi](/source/Doi_(identifier)):[10.1111/j.1096-3642.2001.tb00635.x](https://doi.org/10.1111%2Fj.1096-3642.2001.tb00635.x).

1. **[^](#cite_ref-JEA94_4-0)** Jenkins, F. A. Jr.; Shubin, N. H.; Amaral, W. W.; Gatesy, S. M.; Schaff, C. R.; Clemmensen, L. B.; Downs, W. R.; Davidson, A. R.; Bonde, N.; Osbaeck, F. (1994). "Late Triassic continental vertebrates and depositional environments of the Fleming Fjord Formation, Jameson Land, East Greenland". *Meddelelser om Grønland, Geoscience*. **32**: 1–25.

1. ^ [***a***](#cite_ref-ingavat_5-0) [***b***](#cite_ref-ingavat_5-1) Ingavat, Rucha; Janvier, Phillippe (1981). "*Cyclotosaurus* cf. *Posthumus* Fraas (Capitosauridae, Stereospondyli) from the Huai Hin Lat Formation (Upper Triassic), Northeastern Thailand". *Geobios*. **14** (6): 711–25. [doi](/source/Doi_(identifier)):[10.1016/S0016-6995(81)80149-0](https://doi.org/10.1016%2FS0016-6995%2881%2980149-0).

1. **[^](#cite_ref-6)** Schoch, Rainer (2008). ["The Capitosauria (Amphibia): characters, phylogeny, and stratigraphy"](https://www.palaeodiversity.org/pdf/01/Palaeodiversity_1_13_189-226.pdf) (PDF). *Palaeodiversity*. **1**: 189–226.

1. **[^](#cite_ref-7)** PATON, R. L. 1974. Capitosauroid labyrinthodonts from the Trias of England. Palaeontology, 17, 253–289, pls 35–36.

1. ^ [***a***](#cite_ref-fraser_8-0) [***b***](#cite_ref-fraser_8-1) Nicholas C. Fraser; Hans-Dieter Sues (1997). [*In the Shadow of the Dinosaurs: Early Mesozoic Tetrapods*](https://books.google.com/books?id=3Ta_uivXdrAC&q=Cyclotosaurus+robustus&pg=PA8). Cambridge University Press. p. 8. [ISBN](/source/ISBN_(identifier)) [0521458994](https://en.wikipedia.org/wiki/Special:BookSources/0521458994).

1. ^ [***a***](#cite_ref-witzmann16_9-0) [***b***](#cite_ref-witzmann16_9-1) [***c***](#cite_ref-witzmann16_9-2) Witzmann, F.; Sachs, S.; Nyhuis, C.J. (2016). ["A new species of Cyclotosaurus (Stereospondyli, Capitosauria) from the Late Triassic of Bielefeld, NW Germany, and the intrarelationships of the genus"](https://www.foss-rec.net/19/83/2016/fr-19-83-2016.pdf) (PDF). *Fossil Record*. **19** (2): 83–100. [doi](/source/Doi_(identifier)):[10.5194/fr-19-83-2016](https://doi.org/10.5194%2Ffr-19-83-2016).

1. **[^](#cite_ref-10)** Konietzko-Meier, Dorota; Werner, Jennifer D.; Wintrich, Tanja; Martin Sander, P. (June 2019). ["A large temnospondyl humerus from the Rhaetian (Late Triassic) of Bonenburg (Westphalia, Germany) and its implications for temnospondyl extinction"](https://link.springer.com/10.1007/s41513-018-0092-0). *Journal of Iberian Geology*. **45** (2): 287–300. [doi](/source/Doi_(identifier)):[10.1007/s41513-018-0092-0](https://doi.org/10.1007%2Fs41513-018-0092-0). [ISSN](/source/ISSN_(identifier)) [1698-6180](https://search.worldcat.org/issn/1698-6180). [S2CID](/source/S2CID_(identifier)) [134049099](https://api.semanticscholar.org/CorpusID:134049099).

## External links

- ["Tetrapoda"](https://web.archive.org/web/20230108213222/http://www.paleofile.com/Demo/Mainpage/Taxalist/Labyrinthodon.htm). *Paleofile*. Archived from [the original](http://www.paleofile.com/Demo/Mainpage/Taxalist/Labyrinthodon.htm) on January 8, 2023.

- ["The Norian Age - 3"](https://web.archive.org/web/20090414130748/http://www.palaeos.com/Mesozoic/Triassic/Norian.3.htm#Cyclotosaurus). *Palaeos*. Archived from [the original](http://www.palaeos.com/Mesozoic/Triassic/Norian.3.htm#Cyclotosaurus) on April 14, 2009.

- ["Cyclotosaurus. Cast of skull"](https://web.archive.org/web/20161112013720/http://fossils.valdosta.edu/fossil_pages/fossils_tri/a15.html). *Fossils.valdosta*. Archived from [the original](http://fossils.valdosta.edu/fossil_pages/fossils_tri/a15.html) on November 12, 2016.

- ["Taxonomic history of the genus *Cyclotosaurus* Fraas, 1889"](https://web.archive.org/web/20070824222352/http://www.fmnh.helsinki.fi/users/haaramo/Metazoa/Deuterostoma/Chordata/amphibia/Limnarchia/History_Cyclotosaurus.html). *Mikko's Phylogeny Archive*. Archived from [the original](http://www.fmnh.helsinki.fi/users/haaramo/Metazoa/Deuterostoma/Chordata/amphibia/Limnarchia/History_Cyclotosaurus.html) on August 24, 2007.

- [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 Cyclotosaurus Wikidata: Q2465083 GBIF: 4815937 IRMNG: 1199532 Open Tree of Life: 4948420 Paleobiology Database: 37095

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