Cyclotosaurus

{{Short description|Extinct genus of temnospondyls}} {{Merging from|Cyclotosaurus buechneri|afd=Cyclotosaurus buechneri|date=April 2026}} {{Automatic taxobox | fossil_range = {{Fossil range|Middle Triassic|Late Triassic}} | image = Cyclotosaurus robustus skull Tubingen.JPG | image_caption = ''C. robustus'' skull, Museum of Paleontology, Tuebingen | taxon = Cyclotosaurus | authority = [[Eberhard Fraas|Fraas]], 1889 | type_species = {{extinct}}'''''Cyclotosaurus robustus''''' | type_species_authority = (Meyer & Plienninger, 1844) | synonyms = *''[[Mastodonsaurus]] robustus'' Meyer & Plienninger, 1844 | subdivision_ranks = Other species | subdivision = *{{extinct}}'''''C. mordax''''' Fraas, 1913 *{{extinct}}'''''C. posthumus''''' Fraas, 1913 *{{extinct}}'''''C. ebrachensis''''' Kuhn, 1932 *{{extinct}}'''''C. hemprichi''''' Kuhn, 1942 *{{extinct}}'''''C. intermedius''''' Sulej & Majer, 2005 *{{extinct}}''[[Cyclotosaurus buechneri|C. buechneri]]'' Witzmann, Sachs & Nyhuis, 2016 *{{extinct}}'''''C.? papilio''''' {{ill|Emil Wepfer|de|lt=Wepfer}}, 1923 *{{extinct}}'''''C. naraserluki''''' Marzola ''et al.'', 2017 }}

'''''Cyclotosaurus''''' is an extinct [[genus]] of [[temnospondyl]] within the [[Family (taxonomy)|family]] [[Mastodonsauridae]]. It was of large size for an [[amphibian]], having a skull length of about {{convert|56|cm|in|abbr=on}}.<ref name="sulej05" /><ref name="Marzola, M. 2017" />

==History== [[Image:Cyclotosaurus mordax.JPG|thumb|upright|''Cyclotosaurus mordax'' skull]] German naturalist [[Eberhard Fraas]] erected the genus ''Cyclotosaurus'' in 1889, with ''C. robustus'' (previously ''Mastodonsaurus robustus'') as the [[type species]].<ref name=damiani/> Several species are known, mainly from Germany and Poland in Central Europe, as well as East Greenland and Thailand.<ref name=JEA94>{{cite journal |last=Jenkins |first=F. A. Jr. |author2=Shubin, N. H. |author3=Amaral, W. W. |author4=Gatesy, S. M. |author5=Schaff, C. R. |author6=Clemmensen, L. B. |author7=Downs, W. R. |author8=Davidson, A. R. |author9=Bonde, N. |author10= Osbaeck, F. |year=1994 |title=Late Triassic continental vertebrates and depositional environments of the Fleming Fjord Formation, Jameson Land, East Greenland |journal=Meddelelser om Grønland, Geoscience |volume=32 |pages=1–25}}</ref><ref name=ingavat>{{Cite journal | last1 = Ingavat | first1 = Rucha | last2 = Janvier | first2 = Phillippe | doi = 10.1016/S0016-6995(81)80149-0 | title = ''Cyclotosaurus'' cf. ''Posthumus'' Fraas (Capitosauridae, Stereospondyli) from the Huai Hin Lat Formation (Upper Triassic), Northeastern Thailand | journal = Geobios | volume = 14 | issue = 6 | pages = 711–25 | year = 1981 }}</ref> The relationships between species is unclear.<ref name=sulej05/>

The name means "round eared lizard" in [[Ancient Greek]], derived from round openings or fenestrae in the cheeks, which are thought to contain structures of the middle ear.<ref>{{cite journal|last=Schoch|first=Rainer|date=2008|title=The Capitosauria (Amphibia): characters, phylogeny, and stratigraphy|journal=Palaeodiversity|volume=1|pages=189–226|url=https://www.palaeodiversity.org/pdf/01/Palaeodiversity_1_13_189-226.pdf}}</ref>

''"Labyrinthodon" pachygnathus'' Owen, 1842 and ''"L." leptognathus'' Owen, 1842 were transferred to ''Cyclotosaurus'', as ''C. pachygnathus'' and ''C. leptognathus'', by Paton (1974).<ref>PATON, R. L. 1974. Capitosauroid labyrinthodonts from the Trias of England. Palaeontology, 17, 253–289, pls 35–36.</ref> However, Damiani (2001) assigned the two species to Mastodonsauroidea indeterminate and Stereospondyli indeterminate.<ref name=damiani/>

===Species===

[[Image:MEPAN kapitozaur (Cyclotosaurus).jpg|thumb|''C. intermedius'' model]] The genus is known from the [[Ladinian]] in the [[Middle Triassic]] to the [[Norian]] in the [[Late Triassic]], and represents the last of the mastodonsaurids.<ref name=damiani>{{cite journal|author=Damiani, Ross J.|year= 2001|title= A systematic revision and phylogenetic analysis of Triassic mastodonsauroids (Temnospondyli: Stereospondyli) |journal=Zoological Journal of the Linnean Society|volume=133|issue=4|pages=379–482|doi=10.1111/j.1096-3642.2001.tb00635.x|doi-access=free}}</ref>

The oldest, questionable, species is ''Cyclotosaurus papilio'', known from a partial skull recovered from the Ladinian (Middle Triassic) age Upper [[Muschelkalk]] beds from [[Baden-Württemberg]] in Germany.<ref name=damiani/> ''Cyclotosaurus robustus'' is known from the [[Carnian]] ([[Late Triassic]]) [[Schilfsandstein Formation]] in [[Stuttgart-Feuerbach]] in Germany, while ''C. ebrachensis'' has been described from the [[Blasensandstein Formation]] in [[Ebrach]].<ref name=fraser>{{cite book|author1=Nicholas C. Fraser |author2=Hans-Dieter Sues |title=In the Shadow of the Dinosaurs: Early Mesozoic Tetrapods|publisher=Cambridge University Press|date=1997|pages=8|isbn=0521458994|url=https://books.google.com/books?id=3Ta_uivXdrAC&q=Cyclotosaurus+robustus&pg=PA8}}</ref> ''Cyclotosaurus intermedius'' has been described from lacustrine deposits dated to the late [[Carnian]] in [[Krasiejów]] 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.<ref name=sulej05>{{Cite journal | last1 = Sulej | first1 = T. | last2 = Majer | first2 = D. | doi = 10.1111/j.1475-4983.2004.00430.x | title = The temnospondyl amphibian ''Cyclotosaurus'' from the Upper Triassic of Poland | journal = Palaeontology | volume = 48 | pages = 157–70 | year = 2005 |url = http://www.paleo.pan.pl/people/Sulej/publications/Sulej_Palaeontology_2005.pdf| doi-access = free }}</ref> ''Cyclotosaurus hemprichi'' is known from the [[Norian]] (Late Triassic) age Knollenmergel of Halberstadt, and ''Cyclotosaurus posthumus'' from the [[Stubensandstein]] (Norian) in [[Pfaffenhofen (district)|Pfaffenhofen]].<ref name=fraser/> A partial skull very similar to ''C. posthumus'' has been recovered from the Norian (Late Triassic) Huai Hin Lat Formation near [[Chulabhorn Dam]] in Northeastern Thailand.<ref name=ingavat/> In 2016 a new species, ''[[Cyclotosaurus buechneri|C. buechneri]]'', was described from the [[Late Triassic]] (middle [[Carnian]]) [[Stuttgart Formation]] of [[Bielefeld]], the northernmost record in Germany.<ref name=witzmann16>{{Cite journal | last1 = Witzmann | first1 = F. | last2 = Sachs | first2 = S. | last3 = Nyhuis | first3 = C.J. | doi = 10.5194/fr-19-83-2016 | title = A new species of Cyclotosaurus (Stereospondyli, Capitosauria) from the Late Triassic of Bielefeld, NW Germany, and the intrarelationships of the genus | journal = Fossil Record | volume = 19 | pages = 83–100 | year = 2016 | issue = 2 |url = http://www.foss-rec.net/19/83/2016/fr-19-83-2016.pdf| doi-access = free }}</ref> In 2017, ''Cyclotosaurus naraserluki'', a new endemic species from the [[Fleming Fjord Formation|Fleming Fjord Fm.]], East Greenland, was described as the closest ''Cyclotosaurus'' species to ''C. mordax'', also being the westernmost and northernmost known species of ''Cyclotosaurus''.<ref name="Marzola, M. 2017">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</ref> In 2019 a ''Cyclotosaurus'' humerus was reported from a Rhaetian aged bone bed within Bonenburg clay pit in eastern [[North Rhine-Westphalia]], Germany. This represents the only definitive non-[[Brachyopoidea|brachyopoid]] Rhaetian temnospondyl, and the last known record of [[Capitosauria]].<ref>{{Cite journal|last1=Konietzko-Meier|first1=Dorota|last2=Werner|first2=Jennifer D.|last3=Wintrich|first3=Tanja|last4=Martin Sander|first4=P.|date=June 2019|title=A large temnospondyl humerus from the Rhaetian (Late Triassic) of Bonenburg (Westphalia, Germany) and its implications for temnospondyl extinction|url=https://link.springer.com/10.1007/s41513-018-0092-0|journal=Journal of Iberian Geology|language=en|volume=45|issue=2|pages=287–300|doi=10.1007/s41513-018-0092-0|s2cid=134049099 |issn=1698-6180|url-access=subscription}}</ref>

{{clade| style=font-size:90%;line-height:90% |label1=[[Capitosauroidea]] |1={{clade |1=''[[Eryosuchus]]'' |2={{clade |1=''[[Kupferzellia]]'' |2={{clade |1=''[[Procyclotosaurus]]'' |2={{clade |1=''[[Paracyclotosaurus]]'' |2={{clade |label1=''[[Mastodonsaurus]]'' |1={{clade |1=''[[Mastodonsaurus|Mastodonsaurus cappelensis]]'' |2=''[[Mastodonsaurus|Mastodonsaurus giganteus]]''}} |2={{clade |1='''''Cyclotosaurus''''' |2={{clade |1=''[[Quasicyclotosaurus]]'' |2=''[[Eocyclotosaurus]]''}} }}}}}}}}}}}}}}

The phylogeny of the genus ''Cyclotosaurus'' according to Witzmann et al. (2016).<ref name=witzmann16 />

{{clade| style=font-size:90%;line-height:90% |label1=''Cyclotosaurus'' |1={{clade |1=''C. robustus'' |2={{clade |1=''[[Cyclotosaurus buechneri|C. buechneri]]'' |2={{clade |1=''C. mordax'' |2={{clade |1=''C. ebrachensis'' |2=''C. intermedius''}} |3={{clade |1=''C. posthumus'' |2=''C. hemprichi''}} }}}}}}}}

See also alternative phylogenies from 2017<ref name="Marzola, M. 2017"/> with the description of ''C. naraserluki.''

==Palaeoecology== ''Cyclotosaurus'' are thought to have been semi-aquatic carnivores, though feeding strategies likely differed between species.<ref name=sulej05/>

==References== {{Reflist|colwidth=33em}}

==External links== * {{cite web|url=http://www.paleofile.com/Demo/Mainpage/Taxalist/Labyrinthodon.htm|title=Tetrapoda|website=Paleofile|archive-url=https://web.archive.org/web/20230108213222/http://www.paleofile.com/Demo/Mainpage/Taxalist/Labyrinthodon.htm|archive-date=January 8, 2023|url-status=dead}} * {{cite web|url=http://www.palaeos.com/Mesozoic/Triassic/Norian.3.htm#Cyclotosaurus|title=The Norian Age - 3|website=Palaeos|archive-url=https://web.archive.org/web/20090414130748/http://www.palaeos.com/Mesozoic/Triassic/Norian.3.htm#Cyclotosaurus|archive-date=April 14, 2009|url-status=dead}} * {{cite web|url=http://fossils.valdosta.edu/fossil_pages/fossils_tri/a15.html|title=Cyclotosaurus. Cast of skull.|website=Fossils.valdosta|archive-url=https://web.archive.org/web/20161112013720/http://fossils.valdosta.edu/fossil_pages/fossils_tri/a15.html|archive-date=November 12, 2016|url-status=dead}} * {{cite web|url=http://www.fmnh.helsinki.fi/users/haaramo/Metazoa/Deuterostoma/Chordata/amphibia/Limnarchia/History_Cyclotosaurus.html|title=Taxonomic history of the genus ''Cyclotosaurus'' Fraas, 1889|website=Mikko's Phylogeny Archive|archive-url=https://web.archive.org/web/20070824222352/http://www.fmnh.helsinki.fi/users/haaramo/Metazoa/Deuterostoma/Chordata/amphibia/Limnarchia/History_Cyclotosaurus.html|archive-date=August 24, 2007|url-status=dead}}

[[Category:Capitosauria]] [[Category:Triassic temnospondyls of Europe]] [[Category:Fossil taxa described in 1889]] [[Category:Taxa named by Eberhard Fraas]]