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An ancestral turtle from the Late Triassic of southwestern China


The origin of the turtle body plan remains one of the great mysteries of reptile evolution. The anatomy of turtles is highly derived, which renders it difficult to establish the relationships of turtles with other groups of reptiles. The oldest known turtle, Proganochelys from the Late Triassic period of Germany1, has a fully formed shell and offers no clue as to its origin. Here we describe a new 220-million-year-old turtle from China, somewhat older than Proganochelys, that documents an intermediate step in the evolution of the shell and associated structures. A ventral plastron is fully developed, but the dorsal carapace consists of neural plates only. The dorsal ribs are expanded, and osteoderms are absent. The new species shows that the plastron evolved before the carapace and that the first step of carapace formation is the ossification of the neural plates coupled with a broadening of the ribs. This corresponds to early embryonic stages of carapace formation in extant turtles, and shows that the turtle shell is not derived from a fusion of osteoderms. Phylogenetic analysis places the new species basal to all known turtles, fossil and extant. The marine deposits that yielded the fossils indicate that this primitive turtle inhabited marginal areas of the sea or river deltas.

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Figure 1: Holotype (IVPP V 15639) of Odontochelys semitestacea gen. et sp. nov.
Figure 2: Paratype (IVPP V 13240) of Odontochelys semitestacea gen. et sp. nov.
Figure 3: Referred specimen (IVPP V 15653) of Odontochelys semitestacea gen. et sp. nov.

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  1. Gaffney, E. S. The comparative osteology of the Triassic turtle Proganochelys . Bull. Am. Mus. Nat. Hist. 194, 1–263 (1990)

    Google Scholar 

  2. Wang, L. et al. Biostratigraphy of Triassic marine reptiles in southwest Guizhou and its adjacent area. Acta Geol. Sin. 75, 349–353 (2001)

    Google Scholar 

  3. Wang, X. et al. The Late Triassic black shales from the Guanling area. Guizhou Province, south-west China: a unique marine reptile and pelagic crinoid fossil Lagerstätte. Palaeontology 51, 27–61 (2008)

    Article  Google Scholar 

  4. Wang, X., Hagdorn, H. & Wang, C. Pseudoplanktonic lifestyle of the Triassic crinoid Traumatocrinus from southwest China. Lethaia 39, 187–193 (2006)

    Article  Google Scholar 

  5. Jiang, D. et al. Guanling biota: a marker of Triassic biotic recovery from end-Permian extinction in the ancient Guizhou sea. Acta Geol. Sin. 79, 729–738 (2005)

    Article  Google Scholar 

  6. Joyce, W. J. Phylogenetic relationships of Mesozoic turtles. Bull. Peabody Mus. Nat. Hist. 48, 3–102 (2007)

    Article  Google Scholar 

  7. Reisz, R. R. & Laurin, M. Owenetta and the origin of turtles. Nature 349, 324–326 (1991)

    Article  ADS  Google Scholar 

  8. Lee, M. S. Y. The origin of the turtle body plan: bridging a famous morphological gap. Science 261, 1716–1720 (1993)

    Article  ADS  CAS  Google Scholar 

  9. Lee, M. S. Y. Correlated progression and the origin of turtles. Nature 379, 812–815 (1996)

    Article  ADS  CAS  Google Scholar 

  10. Rieppel, O. & deBraga, M. Turtles as diapsid reptiles. Nature 384, 453–455 (1996)

    Article  ADS  CAS  Google Scholar 

  11. Rieppel, O. & Reisz, R. R. The origin and early evolution of turtles. Annu. Rev. Ecol. Syst. 30, 1–22 (1999)

    Article  Google Scholar 

  12. Rieppel, O. Studies on skeleton formation in reptiles. Patterns of ossification in the skeleton of Chelydra serpentina Linnaeus (Reptilia, Testudines). J. Zool. 231, 487–509 (1993)

    Article  Google Scholar 

  13. Scheil, C. A. Osteology and skeletal development of Apalone spinifera (Reptilia: Testudines: Trionychidae). J. Morphol. 256, 42–78 (2003)

    Article  Google Scholar 

  14. Sheil, C. A. & Greenbaum, E. Reconsideration of skeletal development of Chelydra serpentina (Reptilia: Testudinata: Chelydridae): evidence for intraspecific variation. J. Zool. 265, 235–267 (2005)

    Article  Google Scholar 

  15. Procter, J. B. A study of the remarkable tortoise, Testudo loveridgii Blgr, and the morphogeny of the chelonian carapace. Proc. Zool. Soc. Lond. 1922, 483–526 (1922)

    Article  Google Scholar 

  16. Gilbert, S. F., Loredo, G. A., Brukman, A. & Burke, A. C. Morphogenesis of the turtle shell: the development of a novel structure in tetrapod evolution. Evol. Dev. 3, 47–58 (2001)

    Article  CAS  Google Scholar 

  17. Scheyer, T. M., Brüllmann, B. & Sánchez-Villagra, M. R. The ontogeny of the shell in side-necked turtles, with emphasis on the homologies of costal and neural bones. J. Morphol. 269, 1008–1021 (2008)

    Article  Google Scholar 

  18. Yntema, C. L. A series of stages in the embryonic development of Chelydra serpentina . J. Morphol. 125, 219–252 (1968)

    Article  CAS  Google Scholar 

  19. Kälin, J. Zur Morphogenese des Panzers bei den Schildkröten. Acta Anat. 1, 144–176 (1945)

    Article  Google Scholar 

  20. Gilbert, S. F., Cebra-Thomas, J. A. & Burke, A. C. in Biology of Turtles (eds Wyneken, J., Godfrey, M. H. & Bels, V.) 1–16 (CRC Press, 2008)

    Google Scholar 

  21. Zangerl, R. The homology of the shell elements in turtles. J. Morphol. 65, 383–406 (1939)

    Article  Google Scholar 

  22. Moss, M. L. Comparative histology of dermal sclerifications in reptiles. Acta Anat. 73, 510–533 (1969)

    Article  CAS  Google Scholar 

  23. Zylbernerg, L. & Castanet, J. New data on the structure and growth of the osteoderms in the reptile Anguis fragilis L. (Anguidae, Squamata). J. Morphol. 186, 327–342 (1985)

    Article  Google Scholar 

  24. Lervrat-Calviac, V. & Zylberg, L. The structure of the osteoderms in the gecko: Tarentola mauritanica . Am. J. Anat. 176, 437–446 (1986)

    Article  Google Scholar 

  25. Scheyer, T. M. & Sander, P. M. Histology of ankylosaur osteoderms: implications for systematics and function. J. Vertebr. Paleontol. 24, 874–893 (2004)

    Article  Google Scholar 

  26. Maine, R. P., de Ricqlès, A., Horner, J. R. & Padian, K. The evolution and function of thyreophoran dinosaur scutes: implications for plate function in stegosaurs. Paleobiology 31, 291–314 (2005)

    Article  Google Scholar 

  27. Vickaryous, M. K. & Hall, B. K. Development of the dermal skeleton in Alligator mississippiensis (Archosauria, Crocodylia) with comments on the homology of osteoderms. J. Morphol. 269, 398–422 (2008)

    Article  Google Scholar 

  28. Scheyer, T. M. & Sander, P. M. Shell bone histology indicates terrestrial paleoecology of basal turtles. Proc. R. Soc. B 274, 1885–1893 (2007)

    Article  Google Scholar 

  29. Versluys, J. Über die Phylogenie des Panzers der Schildkröten und über die Verwandtschaft der Lederschildkröte (Dermochelys coriacea). Paläontol. Z. 1, 321–347 (1914)

    Article  Google Scholar 

  30. Joyce, W. G. & Gauthier, J. A. Paleoecology of Triassic stem turtles sheds new light on turtle origins. Proc. R. Soc. B 271, 1–5 (2003)

    Article  Google Scholar 

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We thank Z. Tang for his help in collecting the specimens; J. Ding and H. Zhou for preparing the specimens; and W. Gao for taking the photos. C.L. and L.-T.W. were supported by the Major Basic Research Projects (2006CB806400) of the Ministry of Science and Technology of China, the National Natural Science Foundation (40772015, 40121202) of China (NNSFC) and a special grant for fossil excavation and preparation of the Chinese Academy of Sciences. X.-C.W. was supported by grants from the Canadian Museum of Nature (RS 34), NNSFC 40772015 and the CAS/SAFEA International Partnership Program for Creative Research Teams. O.R. was supported by a stipend from M. Tang.

Author Contributions C.L. designed the project. C.L., X.-C.W., O.R., L.-T.W. and L.-J.Z. performed the research. C.L., X.-C.W. and O.R. contributed to the writing.

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Correspondence to Chun Li or Xiao-Chun Wu.

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Li, C., Wu, XC., Rieppel, O. et al. An ancestral turtle from the Late Triassic of southwestern China. Nature 456, 497–501 (2008).

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