Naturwissenschaften

, Volume 97, Issue 4, pp 423–428 | Cite as

Cretaceous choristoderan reptiles gave birth to live young

Short Communication

Abstract

Viviparity (giving birth to live young) in fossil reptiles has been known only in a few marine groups: ichthyosaurs, pachypleurosaurs, and mosasaurs. Here, we report a pregnant specimen of the Early Cretaceous Hyphalosaurus baitaigouensis, a species of Choristodera, a diapsid group known from unequivocal fossil remains from the Middle Jurassic to the early Miocene (about 165 to 20 million years ago). This specimen provides the first evidence of viviparity in choristoderan reptiles and is also the sole record of viviparity in fossil reptiles which lived in freshwater ecosystems. This exquisitely preserved specimen contains up to 18 embryos arranged in pairs. Size comparison with small free-living individuals and the straight posture of the posterior-most pair suggest that those embryos were at term and had probably reached parturition. The posterior-most embryo on the left side has the head positioned toward the rear, contrary to normal position, suggesting a complication that may have contributed to the mother’s death. Viviparity would certainly have freed species of Hyphalosaurus from the need to return to land to deposit eggs; taking this advantage, they would have avoided intense competition with contemporaneous terrestrial carnivores such as dinosaurs.

Keywords

Reptiles Choristoderan Hyphalosaur Viviparity 

References

  1. Andrews RM, Mathies T (2000) Natural history of reptilian development: physiological constraints on the evolution of viviparity. BioSci 50:227–238CrossRefGoogle Scholar
  2. Blackburn DG (1993) Standardized criteria for the reproduction of reproductive modes in squamate reptiles. Herpetologica 49(1):118–132Google Scholar
  3. Blackburn DG (1994) Discrepant usage of the term ‘ovoviviparity’ in the herpetological literature. Herpetological J 4:65–72Google Scholar
  4. Böttcher R (1990) Neue Erkenntnisse über die Fortpflanzungsbiologie der Ichthyosaurier (Reptilia). Stuttgarter Beitr Naturk B 164:1–51Google Scholar
  5. Chang M-m, Chen P-j, Wang y-q, Wang Y (2003) The Jehol Biota—the emergence of feathered dinosaurs, beaked birds and flowering plants. Shanghai Science & Technical Publishers, ShanghaiGoogle Scholar
  6. Cheng Y-n, Wu X-c, Ji Q (2004) Triassic marine reptiles gave birth to live young. Nature 432:383–386CrossRefPubMedGoogle Scholar
  7. Cope ED (1876) On some extinct reptiles and Batrachia from the Judith River and Fox Hills beds of Montana. Proc Acad Nat Sci Phil 28:340–359Google Scholar
  8. Cope ED (1884) The Choristodera. Am Nat 17:815–817Google Scholar
  9. Deeming DC, Halstead LB, Manabe M, Unwin DM (1993) An ichthyosaur embryo from the Lower Lias (Jurassic: Hettangian) of Somerset, England, with comments on the reproductive biology of ichthyosaurs. Mod Geol 18:423–442Google Scholar
  10. Erickson BR (1972) The lepidosaurian reptile Champsosaurus in North America. Monogr Sci Mus Minn (Paleontol) 1:1–91Google Scholar
  11. Evans SE (1990) The skull of Cteniogenys, a choristodere (Reptilia: Archosauromorpha) from the Middle Jurassic of Oxfordshire. Zoo J Linn Soc 99:205–237CrossRefGoogle Scholar
  12. Evans SE, Manabe M (1999) A choristoderan reptile from the lower Cretaceous of Japan. Spec Pap Paleontol 60:101–119Google Scholar
  13. Evans SE, Klembara J (2005) A choristoderan reptile (Reptilia: Diapsida) from the lower Miocene of Northwest Bohemia (Czech Republic). J Vert Paleontol 25:171–184CrossRefGoogle Scholar
  14. Gao K-q, Fox RC (1998) New choristoderes (Reptilia: Diapsida) from the Upper Cretaceous and Palaeocene, Alberta and Saskatchewan, Canada, and phylogenetic relationships of the Choristodera. Zool J Linn Soc 124:303–353CrossRefGoogle Scholar
  15. Gao K, Ksepka DT (2008) Osteology and taxonomic revision of Hyphalosaurus (Diapsida: Choristodera) from the Lower Cretaceous of Liaoning, China. J Anat 212:737–768CrossRefGoogle Scholar
  16. Gao K, Tang Z, Wang X (1999) A long-necked diapsid reptile from the Upper Jurassic/Lower Cretaceous of Liaoning Province, northeastern China. Vert PalAsiat 37:1–8Google Scholar
  17. Guillette LJ Jr (1993) The evolution of viviparity in lizards. BioSci 43:742–751CrossRefGoogle Scholar
  18. Ji Q, Chen W, Wang W-l, Jin X et al (2004a) Mesozoic Jehol Biota of Western Liaoning, China. Geological Publishing House [in Chinese], BeijingGoogle Scholar
  19. Ji Q, Cheng Y, You H, Lu J, Yuan C (2004b) The first soft-shelled eggs with embryos from Late Mesozoic Jehol Biota of western Liaoning, China. Acta Geosci Sin 25:275–285Google Scholar
  20. Ji Q, Ji S-a, Lü J, You H, Yuan C-x (2006) Embryos of early cretaceous choristoderan (Reptilia) from the Jehol Biota in Western Liaoning, China. J Paleontol Soc Korea 22:111–118Google Scholar
  21. Smith SA, Shine R (1997) Intraspecific variation in reproductive mode within the scincid lizard Saiphos equalis. Aust J Zool 45:435–445CrossRefGoogle Scholar
  22. Storrs GW, Gower DJ (1993) The earliest possible choristodere (Diapsida) and gaps in the fossil record of semi-aquatic reptiles. J Geol Soc (Lond) 150:1103–1107CrossRefGoogle Scholar
  23. Storrs GW, Gower DJ, Large NF (1996) The diapsid reptile, Pachystropheus rhaeticus, a probable choristodere from the Rhaetian of Europe. Palaeontol 39:323–349Google Scholar
  24. Thompson MB, Speake BK (2004) Egg morphology and composition. In: Deeming CD (ed) Reptilian incubation, environment, evolution and behavior. Nottingham University Press, Nottingham, pp 45–74Google Scholar
  25. Thompson MB, Adams SM, Herbert JF, Biazik JM, Murphy CR (2004) Placental function in lizards. In: International congress series. Animals and environments. Proceedings of the third international conference of comparative physiology and biochemistry, vol 1275, December 2004, Elsevier. New York, pp 218–225. doi:10.1016/j.ics.2004.08.055
  26. Wu X-c, Li Z, Zhou B-c, Dong Z-m (2003) A polydactylous amniote from the Triassic period. Nature 426:516CrossRefPubMedGoogle Scholar

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  1. 1.Institute of GeologyChinese Academy of Geological SciencesBeijingChina
  2. 2.Canadian Museum of NatureOttawaCanada
  3. 3.National Museum of Natural ScienceTaichungChina

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