Cyclotosaurus

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Cyclotosaurus
Temporal range: Middle Triassic–Late Triassic
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
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, 1923
  • †C. naraserluki Marzola et al., 2017
Synonyms

Cyclotosaurus is an extinct

temnospondyl within the family Mastodonsauridae. It was of great size for an amphibian, had an elongated skull up to 56 cm (22 in).[1][2]

Etymology

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.[3]

History

Cyclotosaurus mordax skull

German naturalist Eberhard Fraas erected the genus Cyclotosaurus in 1889, with C. robustus (previously Mastodonsaurus robustus) as the type species.[4] Several species are known, mainly from Germany and Poland in Central Europe, as well as East Greenland and Thailand.[5][6] The relationships between species is unclear.[1]

"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.[4]

Palaeontology

Cyclotosaurus 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.[4]

Life restoration of Cyclotosaurus

The oldest, questionable, species is Cyclotosaurus papilio, known from a partial skull recovered from the Ladinian (Middle Triassic) age Upper

Stubensandstein (Norian) in Pfaffenhofen.[8] 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.[6] In 2016 a new species, C. buechneri, was described from the Late Triassic (middle Carnian) Stuttgart Formation of Bielefeld, the northernmost record in Germany.[9]
In 2017, Cyclotosaurus naraserluki, a new endemic species from the 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.[2] 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-brachyopoid Rhaetian temnospondyl, and the last known record of Capitosauria.[10]

Phylogeny

The phylogeny of

Capitosauroidea according to Witzmann et al. (2016).[9]

Capitosauroidea

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.

Ecology

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

References

  1. ^
    doi:10.1111/j.1475-4983.2004.00430.x
    .
  2. ^ a b c 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
  3. ^ Schoch, Rainer (2008). "The Capitosauria (Amphibia): characters, phylogeny, and stratigraphy" (PDF). Palaeodiversity. 1: 189–226.
  4. ^
    doi:10.1111/j.1096-3642.2001.tb00635.x
    .
  5. ^ 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.
  6. ^
    doi:10.1016/S0016-6995(81)80149-0
    .
  7. ^ PATON, R. L. 1974. Capitosauroid labyrinthodonts from the Trias of England. Palaeontology, 17, 253–289, pls 35–36.
  8. ^
    ISBN 0521458994
    .
  9. ^
    doi:10.5194/fr-19-83-2016
    .
  10. S2CID 134049099
    .

External links
Retrieved from "https://en.wikipedia.org/w/index.php?title=Cyclotosaurus&oldid=1213285066"