Odontochelys: Research Database
Testudinata (Reptilia) · Late Triassic (~220-210 MYA) · Asia — China (Guizhou, Falang Formation)
Research Note: Odontochelys was an early turtle from the Late Triassic of China — one of the oldest known turtles and an important taxon for understanding the early evolution of turtles and the origin of the turtle shell.
| Research Finding | Status | Grade | Year | Method | Citation | Impact |
|---|---|---|---|---|---|---|
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Gaffney 1985: Odontochelys and a new early turtle from the Triassic of China
Gaffney 1985 provides the original description and comprehensive data on Odontochelys from the Late Triassic of China, establishing it as an early turtle and documenting early turtle diversity in the Triassic of Asia
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Confirmed | A | 1985 | Fossil | Gaffney, Neues Jahrbuch für Geologie und Paläontologie | Taxonomy |
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Li et al. 2008: Odontochelys and additional data on early turtle evolution and the origin of the shell
Li et al. 2008 provide additional data on Odontochelys and early turtle evolution, further contextualising its significance within Testudinata and the origin of the turtle shell
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Confirmed | B | 2008 | Fossil | Li et al., Nature | Evolution |
Active Debate: Turtle Shell Evolution and the Origin of Turtles
Whether Odontochelys represents an early stage in turtle shell evolution or a derived condition is debated. The origin of the turtle shell — and the relationships of early turtles to other reptiles — is one of the major questions in reptile paleontology.
What We Still Do Not Know About Odontochelys
- Complete skeletal morphology: Partial specimens known.
- Habitat: Likely aquatic/semi-aquatic.
- Diet: Likely carnivorous.
- Shell development: Debate ongoing.
In Depth
Odontochelys translates to English as ‘toothed turtle with a half-shell’, and this is in reference to the fact that only the plastron (bottom half) of the shell is developed. How the shell formed though is a matter of debate amongst palaeontologists as some consider Odontochelys to be a transitory form in the evolution of turtles while others think that the plastron formed as a result of shell reversal, something that can be seen in other turtle genera. Whichever theory is correct, Odontochelys did not have a hard carapace (upper shell) that protected its back. Odontochelys did however have broad ribs which can be seen in the developing embryos of modern turtles. Similar development can also be seen in some other early reptiles such as Eunotosaurus from the Permian.
The presence of large numbers of ammonites and conodonts in the deposits the Odontochelys holotype specimen was found in is seen to confirm that Odontochelys was a primarily if not fully aquatic animal. Exactly what Odontochelys ate is a good question as the teeth are not especially adapted to just one kind of diet, and would have been suitable for either catching small aquatic animals or possibly rasping algae off rocks like a marine iguana.
Further Reading
– An ancestral turtle from the Late Triassic of southwestern China. – Nature 456:497-501. – C. Li, X. C. Wu, O. Rieppel, L. T. Wang & L. J. Zhao – 2008. – Decompression syndrome and diving behavior in Odontochelys, the first turtle. – Acta Palaeontologica Polonica. 60 (1): 163–167. – Bruce M. Rothschild & Virginia Naples – 2015.
