Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

A transitional snake from the Late Cretaceous period of North America


Snakes are the most diverse group of lizards1, but their origins and early evolution remain poorly understood owing to a lack of transitional forms. Several major issues remain outstanding, such as whether snakes originated in a marine2,3,4 or terrestrial5,6 environment and how their unique feeding mechanism evolved1,7,8. The Cretaceous Coniophis precedens was among the first Mesozoic snakes discovered9, but until now only an isolated vertebra has been described9,10 and it has therefore been overlooked in discussions of snake evolution. Here we report on previously undescribed material11 from this ancient snake, including the maxilla, dentary and additional vertebrae. Coniophis is not an anilioid as previously thought11; a revised phylogenetic analysis of Ophidia shows that it instead represents the most primitive known snake. Accordingly, its morphology and ecology are critical to understanding snake evolution. Coniophis occurs in a continental floodplain environment, consistent with a terrestrial rather than a marine origin; furthermore, its small size and reduced neural spines indicate fossorial habits, suggesting that snakes evolved from burrowing lizards. The skull is intermediate between that of lizards and snakes. Hooked teeth and an intramandibular joint indicate that Coniophis fed on relatively large, soft-bodied prey. However, the maxilla is firmly united with the skull, indicating an akinetic rostrum. Coniophis therefore represents a transitional snake, combining a snake-like body and a lizard-like head. Subsequent to the evolution of a serpentine body and carnivory, snakes evolved a highly specialized, kinetic skull, which was followed by a major adaptive radiation in the Early Cretaceous period. This pattern suggests that the kinetic skull was a key innovation that permitted the diversification of snakes.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Prices vary by article type



Prices may be subject to local taxes which are calculated during checkout

Figure 1: Dentary of Coniophis precedens.
Figure 2: Maxilla of Coniophis precedens.
Figure 3: Vertebrae of Coniophis precedens.
Figure 4: Skull in lizards, Coniophis and modern snakes.
Figure 5: Phylogeny of Ophidia, showing relationships of Coniophis and evolution of cranial kinesis.


  1. Greene, H. W. Snakes: the Evolution of Mystery in Nature (Univ. California Press, 1997)

    Google Scholar 

  2. Caldwell, M. W. & Lee, M. S. Y. A snake with legs from the marine Cretaceous of the Middle East. Nature 386, 705–709 (1997)

    Article  CAS  ADS  Google Scholar 

  3. Cope, E. D. On the reptilian orders Pythonomorpha and Streptosauria. Proc. Bost. Soc. Nat. Hist. 12, 250–267 (1869)

    Google Scholar 

  4. Lee, M. S. Y. Molecular evidence and marine snake origins. Biol. Lett. 1, 227–230 (2005)

    Article  CAS  Google Scholar 

  5. Apesteguía, S. & Zaher, H. A Cretaceous terrestrial snake with robust hindlimbs and a sacrum. Nature 440, 1037–1040 (2006)

    Article  ADS  Google Scholar 

  6. Vidal, N. & Hedges, S. B. Molecular evidence for a terrestrial origin of snakes. Proc. R. Soc. Lond. B 271, S226–S229 (2004)

    Article  CAS  Google Scholar 

  7. Lee, M. S. Y., Bell, G. L. & Caldwell, M. W. The origin of snake feeding. Nature 400, 655–659 (1999)

    Article  CAS  ADS  Google Scholar 

  8. Cundall, D. & Greene, H. W. in Feeding: Form, Function, and Evolution in Terrestrial Vertebrates (ed. Schwenk, K. ) 293–333 (Academic, 2000)

    Book  Google Scholar 

  9. Marsh, O. C. Notice of new reptiles from the Laramie Formation. Am. J. Sci. 43, 449–453 (1892)

    Article  ADS  Google Scholar 

  10. Gilmore, C. W. Fossil snakes of North America. Geol. Soc. Am. Bull. 9, 1–96 (1938)

    Google Scholar 

  11. Estes, R. Fossil Vertebrates from the Late Cretaceous Lance Formation, Eastern Wyoming. Univ. Calif. Publ. Geol. Sci. 49, 140–141 (1964)

    Google Scholar 

  12. Zaher, H., Apesteguía, S. & Scanferla, C. A. The anatomy of the Upper Cretaceous snake Najash rionegrina Apesteguía & Zaher, 2006, and the evolution of limblessness in snakes. Zool. J. Linn. Soc. 156, 801–826 (2009)

    Article  Google Scholar 

  13. Cundall, D. & Irish, F. in Biology of the Reptilia Vol. 20 (eds Gans, C., Gaunt, A. S. & Adler, K. ) 349–692 (Society for the Study of Amphibians and Reptiles, 2008)

    Google Scholar 

  14. Hoffstetter, R. in Traité de Paléontologie (ed. Piveteau, J. ) 606–662 (Maison et Cie, 1955)

    Google Scholar 

  15. Rage, J.-C. & Augé, M. Squamate reptiles from the middle Eocene of Lissieu (France). Geobios 43, 253–268 (2010)

    Article  Google Scholar 

  16. Scanlon, J. D. & Lee, M. S. Y. Varanoid-like dentition in primitive snakes (Madtsoiidae). J. Herpetol. 36, 100–106 (2002)

    Article  Google Scholar 

  17. Cundall, D. Feeding behavior in Cylindrophis and its bearing on the evolution of alethinophidian snakes. J. Zool. 237, 353–376 (1995)

    Article  Google Scholar 

  18. Wilson, J. A., Mohabey, D. M., Peters, S. E. & Head, J. J. Predation upon hatchling dinosaurs by a new snake from the Late Cretaceous of India. PLoS Biol. 8, e1000322 (2010)

    Article  Google Scholar 

  19. Zaher, H. & Scanferla, C. A. The skull of the Upper Cretaceous snake Dinilysia patagonica Smith-Woodward 1901, and its phylogenetic position revisited. Zool. J. Linn. Soc. 164, 194–238 (2012)

    Article  Google Scholar 

  20. Scanlon, J. D. & Lee, M. S. Y. The Pleistocene serpent Wonambi and the early evolution of snakes. Nature 403, 416–420 (2000)

    Article  CAS  ADS  Google Scholar 

  21. Scanlon, J. D. Skull of the large non-macrostomatan snake Yurlunggur from the Australian Oligocene. Nature 439, 839–842 (2006)

    Article  CAS  ADS  Google Scholar 

  22. Rage, J.-C. & Albino, A. M. Dinilysia patagonica (Reptilia, Serpentes): matériel vertébral additionel du Crétacé supérieur d’Argentine. Étude complémentaire des vertèbres, variations intraspécifiques etintracolumnaires. Neues Jahrb. Geol. Paläontol. Monatsh. 1989, 433–447 (1989)

    Google Scholar 

  23. Hoffstetter, R. & Gasc, J.-P. Vertebrae and ribs of modern reptiles.. in Biology of the Reptilia Vol. 1 (ed. Gans, C. ) 201–310 (Academic, 1969).

  24. Prasad, G. V. R. Rage, J.-C. Amphibians and squamates from the Maastrichtian of Naskal, India. Cretac. Res. 16, 95–107 (1995)

    Article  Google Scholar 

  25. Caldwell, M. W. & Albino, A. M. Palaeoenvironment and palaeoecology of three Cretaceous snakes: Pachyophis, Pachyrhachis, and Dinilysia . Acta Palaeontol. Pol. 46, 203–218 (2001)

    Google Scholar 

  26. Kearney, M. Systematics of the Amphisbaenia (Lepidosauria: Squamata) based on morphological evidence from recent and fossil forms. Herpetological Monogr. 17, 1–74 (2003)

    Article  Google Scholar 

  27. Rage, J.-C. & Escuil, F. The Cenomanian: stage of hindlimbed snakes. Carnets Géol. 2003, 2003/01. (2003)

  28. Rage, J.-C. & Werner, C. Mid-Cretaceous (Cenomanian) snakes from Wadi Abu Hashim, Sudan: the earliest snake assemblage. Palaeontol. Afr. 35, 85–110 (1999)

    Google Scholar 

  29. Gardner, J. D. & Cifelli, R. L. A primitive snake from the Cretaceous of Utah. Spec. Pap. Palaeontol. 60, 87–100 (1999)

    Google Scholar 

Download references


We thank the curators and staff of the American Museum of Natural History, the University of California Museum of Paleontology and the Yale Peabody Museum of Natural History, and the staff of Digimorph at the University of Texas at Austin, for specimen access. We are especially grateful to J. Head for discussions about snake vertebrae, which prevented a major error in the assignment of material to Coniophis. This research was funded in part by US NSF grant DEB-0132227 to J.A.G. N.R.L. was funded by the Yale Institute for Biospheric Studies.

Author information

Authors and Affiliations



N.R.L. designed the research, identified specimens, collected data, performed the phylogenetic analysis and wrote the paper. B.-A.S.B. designed the research, collected data and wrote the paper. J.A.G. collected data, contributed data and wrote the paper.

Corresponding author

Correspondence to Nicholas R. Longrich.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information 1

This file contains Supplementary Text and Data 1-2, Supplementary Figures 1-2 and additional references. (PDF 554 kb)

Supplementary Information 2

This file contains Supplementary Text and Data, Supplementary Materials, Supplementary Results, a Supplementary Discussion and additional references. (PDF 1206 kb)

Supplementary Information 3

This file contains the Supplementary Character illustrations 155-228. (PDF 3157 kb)

Supplementary Information 4

This file contains the Supplementary Character-taxon matrix. (TXT 8 kb)

PowerPoint slides

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Longrich, N., Bhullar, BA. & Gauthier, J. A transitional snake from the Late Cretaceous period of North America. Nature 488, 205–208 (2012).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing