Letter | Published:

Mammalian biodiversity on Madagascar controlled by ocean currents

Nature volume 463, pages 653656 (04 February 2010) | Download Citation

Abstract

Madagascar hosts one of the world’s most unusual, endemic, diverse and threatened concentrations of fauna1. To explain its unique, imbalanced biological diversity, G. G. Simpson proposed the ‘sweepstakes hypothesis’, according to which the ancestors of Madagascar’s present-day mammal stock rafted there from Africa2. This is an important hypothesis in biogeography and evolutionary theory for how animals colonize new frontiers1,3,4,5, but its validity is questioned5,6,7,8,9. Studies suggest that currents were inconsistent with rafting to Madagascar9 and that land bridges provided the migrants’ passage5,6,7,8. Here we show that currents could have transported the animals to the island and highlight evidence inconsistent with the land-bridge hypothesis. Using palaeogeographic reconstructions and palaeo-oceanographic modelling, we find that strong surface currents flowed from northeast Mozambique and Tanzania eastward towards Madagascar during the Palaeogene period, exactly as required by the ‘sweepstakes process’. Subsequently, Madagascar advanced north towards the equatorial gyre and the regional current system evolved into its modern configuration with flows westward10 from Madagascar to Africa. This may explain why no fully non-aquatic land mammals have colonized Madagascar since the arrival of the rodents and carnivorans during the early-Miocene epoch. One implication is that rafting may be the dominant means of overseas dispersal in the Cenozoic era when palaeocurrent directions are properly considered.

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References

  1. 1.

    & Has vicariance or dispersal been the predominant biogeographic in Madagascar? Only time will tell. Annu. Rev. Ecol. Evol. Syst. 37, 405–431 (2006)

  2. 2.

    Mammals and land bridges. J. Wash. Acad. Sci. 30, 137–163 (1940)

  3. 3.

    Is a new paradigm emerging for oceanic island biogeography? J. Biogeogr. 34, 753–757 (2007)

  4. 4.

    & The ecology of rafting in the marine environment. III. Biogeographical and evolutionary consequences. Oceanogr. Mar. Biol. 44, 323–429 (2006)

  5. 5.

    in Elwyn Simons: A Search for Origins (eds Fleagle, J. G. & Gilbert, C. C.) 397–408 (Springer, 2008)

  6. 6.

    Historical biogeography of the strepsirhine primates of Madagascar. Folia Primatol. (Basel) 77, 477–487 (2006)

  7. 7.

    , & Reconciling the origins of Africa, India and Madagascar with vertebrate dispersal scenarios. Folia Primatol. (Basel) 77, 399–418 (2006)

  8. 8.

    Implications of recent geological investigations of the Mozambique Channel for the mammalian colonization of Madagascar. Proc. R. Soc. Lond. B 264, 663–665 (1997)

  9. 9.

    , , & Did lemurs have sweepstake tickets? An exploration of Simpson’s model for the colonization of Madagascar by mammals. J. Biogeogr. 33, 221–235 (2006)

  10. 10.

    & Effect of ocean gateways on the global ocean circulation in the late Oligocene and the early Miocene. Paleoceanography 21, PA1011 (2006)

  11. 11.

    , & in The Natural History of Madagascar (eds Goodman, S. M. & Benstead, J. P.) 1159–1186 (Chicago Univ. Press, 2003)

  12. 12.

    et al. Single origin of Malagasy Carnivora from an African ancestor. Nature 421, 734–737 (2003)

  13. 13.

    et al. Asynchronous colonization of Madagascar by the four endemic clades of primates, tenrecs, carnivores, and rodents as inferred from nuclear genes. Syst. Biol. 54, 719–730 (2005)

  14. 14.

    Origin of Madagascar’s extant fauna: a perspective from amphibians, reptiles and other non-flying vertebrates. Ital. J. Zool. (Modena) 71 (suppl.). 217–228 (2004)

  15. 15.

    , , , & Multiple colonization of Madagascar and Socotra by colubrid snakes: evidence from nuclear and mitochondrial gene phylogenies. Proc. R. Soc. Lond. B 270, 2613–2621 (2003)

  16. 16.

    Fossil molar from a Madagascan marsupial. Nature 412, 497–498 (2001)

  17. 17.

    et al. Late Cretaceous terrestrial vertebrates from Madagascar: implications for Latin American biogeography. Ann. Mo. Bot. Gard. 93, 178–208 (2006)

  18. 18.

    Taxonomy, habits, and relationships of the subfossil Madagascan hippopotami Hippopotamus lemerlei and H. madagascariensis. J. Vertebr. Paleontol. 9, 241–268 (1989)

  19. 19.

    , & The separation of Madagascar and Africa. Science 220, 67–69 (1983)

  20. 20.

    & Gondwana to Asia: plate tectonics, paleogeography and the biological connectivity of the Indian sub-continent from the Middle Jurassic through latest Eocene (166–35 Ma). Earth Sci. Rev. 88, 145–166 (2008)

  21. 21.

    Lemuriform origins as viewed from the fossil record. Folia Primatol. (Basel) 77, 446–464 (2006)

  22. 22.

    & The Africa–Madagascar connection and mammalian migrations. J. Afr. Earth Sci. 44, 270–276 (2006)

  23. 23.

    Petrological and geochemical investigations of rocks from the Davie Fracture Zone (Mozambique Channel) and some tectonic implications. J. Afr. Earth Sci. 15, 321–339 (1992)

  24. 24.

    , & in Natural Change and Human Impact in Madagascar (eds Goodman, S. D. & Patterson, B. D.) 3–43 (Smithsonian Inst. Press, 1997)

  25. 25.

    Lemur origins: rafting by groups of hibernators? Folia Primatol. (Basel) 71, 422–425 (2000)

  26. 26.

    , & Indian Ocean circulation and climate variability. Rev. Geophys. 47, RG1002 (2009)

  27. 27.

    , & Variability of the southwest Indian Ocean. Phil. Trans. R. Soc. A 363, 63–76 (2005)

  28. 28.

    , , & The low-resolution CCSM3. J. Clim. 19, 2545–2566 (2006)

  29. 29.

    et al. Last glacial maximum and Holocene climate in CCSM3. J. Clim. 19, 2526–2544 (2006)

  30. 30.

    et al. Global cooling during the Eocene-Oligocene climate transition. Science 323, 1187–1190 (2009)

  31. 31.

    , & in Causes and Consequences of Globally Warm Climates in the Early Palaeogene (eds Wing, S. L., Gingerich, P. D., Schmitz, B. & Thomas, E.) 25–47 (GSA Special Paper 369, Geological Society of America, 2003)

  32. 32.

    & The ocean circulation in the southern hemisphere and its climatic impacts in the Eocene. Palaeogeogr. Palaeoclimatol. Palaeoecol. 231, 9–28 (2006)

  33. 33.

    et al. Eocene circulation of the Southern Ocean: was Antarctica kept warm by subtropical waters? Paleoceanography 19, PA4026 (2004)

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Acknowledgements

M. Nowak, W. de Ruijter, I. Tattersall and A. Yoder supplied reprints. J. Aitchison, R. Corlett and A. Switzer are thanked for sharing information. M.H. is supported by US National Science Foundation (NSF) grant 0927946-ATM and uses the US National Center for Atmospheric Research CCSM, which is supported by the NSF. M.H. acknowledges conversations with P. Koch and D. Raup on vicariance biogeography. All computing was performed at the Rosen Center for Advanced Computing, which is part of Information Technology at Purdue, Purdue University.

Author Contributions J.R.A. initiated the study and was primarily responsible for the geologically related aspects. M.H. carried out the palaeo-oceanographic modelling and its interpretation. Both authors contributed to the writing of the paper.

Author information

Affiliations

  1. Department of Earth Sciences, University of Hong Kong, Pokfulam Road, Hong Kong, China

    • Jason R. Ali
  2. Earth and Atmospheric Sciences Department and the Purdue Climate Change Research Center, Purdue University, West Lafayette, Indiana 47907, USA

    • Matthew Huber

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Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Matthew Huber.

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DOI

https://doi.org/10.1038/nature08706

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