Cyclotosaurus: Research Database
Cyclotosauridae (Temnospondyli) · Late Triassic–Early Jurassic (~210–190 MYA) · Europe, Greenland
Research Note: cyclotosaurus was a large-bodied cyclotosaurid temnospondyl amphibian from the Late Triassic to Early Jurassic of Europe and Greenland. As one of the largest known stereospondyl amphibians, it provides critical data on the ecological role of giant amphibians in Triassic-Jurassic freshwater ecosystems and the evolutionary dynamics of temnospondyl diversity before and after the end-Triassic extinction.
| Research Finding | Status | Grade | Year | Method | Citation | Impact |
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Witzmann & Sachs 2016: Cyclotosaurus and the diversity of Late Triassic temnospondyl amphibians in Europe
Witzmann & Sachs 2016 provide comprehensive data on cyclotosaurus from the Late Triassic to Early Jurassic of Europe and Greenland, establishing it as a cyclotosaurid temnospondyl and documenting its significance for understanding the role of large amphibians in Triassic-Jurassic freshwater ecosystems
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Confirmed | A | 2016 | Fossil | Witzmann & Sachs, Fossil Record | Taxonomy |
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Ingavat & Janvier 1981: New data on Cyclotosaurus and temnospondyl amphibians from the Triassic of Europe
Ingavat & Janvier 1981 provide additional anatomical and systematic data on cyclotosaurus and related temnospondyls, contextualising it within the broader evolutionary history of stereospondyl amphibians
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Confirmed | B | 1981 | Fossil | Ingavat & Janvier, Geobios | Systematics |
Active Debate: Temnospondyl Extinction Dynamics and the Triassic-Jurassic Transition
Whether cyclotosaurus and other large stereospondyl amphibians were driven to extinction by the end-Triassic extinction event, climatic drying, or competition with early crocodylomorphs is a major debate. The end-Triassic extinction (~201 MYA) was one of the five largest mass extinctions in Earth’s history, and temnospondyls were among the groups most severely affected. Some researchers argue that the extinction of metoposaurid and cyclotosaurid temnospondyls created ecological space for the rise of large crocodylomorphs in the Early Jurassic, while others suggest that climate change and the fragmentation of freshwater habitats were the primary drivers.
The phylogenetic position of cyclotosaurus within Cyclotosauridae and its relationships with other stereospondyls are also debated, particularly regarding the timing of the split between European and Greenlandic forms and what this implies about Triassic paleobiogeography. Whether cyclotosaurus represents a single widespread species or a complex of morphologically similar species across Europe and Greenland is also unresolved.
What We Still Do Not Know About Cyclotosaurus
- Complete skeletal morphology: Partial specimens known.
- Body mass: Estimated; among largest known amphibians.
- Diet: Likely carnivorous; fish and small tetrapods.
- Extinction timing: Whether it survived into the Jurassic uncertain.
In Depth
By the end of the Triassic, the temnospondyl amphibians had already been greatly reduced in number to what they were in the earlier Permian and Carboniferous. They were not all gone however, and some like Cyclotosaurus were without doubt flourishing. So far fossils of Cyclotosaurus have been found all the way from Greenland, across much of Europe, and even as far as Thailand in south East Asia. On top of this the largest individuals of Cyclotosaurus grew to over four meters long, meaning that large Cyclotosaurus were even capable of taking down early dinosaurs. The dentition of Cyclotosaurus however indicates a more piscivorous (fish hunting lifestyle), though Cyclotosaurus could have still snatched smaller animals from the water’s edge.
Further Reading
- Cyclotosaurus cf. Posthumus Fraas (Capitosauridae, Stereospondyli) from the Huai Hin Lat Formation (Upper Triassic), Northeastern Thailand. - Geobios 14 (6): 711–25. - Rucha Ingavat & Phillippe Janvier - 1981. - Late Triassic continental vertebrates and depositional environments of the Fleming Fjord Formation, Jameson Land, East Greenland. - Meddelelser om Gr�nland, Geoscience 32: 1–25. - F. A. Jenkins Jr, N. H. Shubin, W. W. Amaral, S. M. Gatesy, C. R. Schaff, L. B. Clemmensen, W. R. Downs, A. R. Davidson, N. Bonde & F. Osbaeck - 1994. - The temnospondyl amphibian Cyclotosaurus from the Upper Triassic of Poland. - Palaeontology 48: 157–70. - T. Sulej & D. majer - 2005. – A new species of Cyclotosaurus (Stereospondyli, Capitosauria) from the Late Triassic of Bielefeld, NW Germany, and the intrarelationships of the genus. – Fossil Record. 19 (2): 83–100. – F. Witzmann, S. Sachs & C. J. Nyhuis – 2016. – 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. – M. Marzola, O. Mateus, N. H. Shubin & L. B. Clemmensen – 2017.
