Abstract
A recently discovered series of mollusc faunas from the late Cenozoic of the eastern Turkana Basin constitutes one of the best documented metazoan fossil sequences. Evolutionary patterns in all lineages conform to the ‘punctuated equilibrium’ model; no ‘gradualistic’ morphological trends occur. These faunas provide the first fine-scaled palaeontological resolution of events during speciation: fundamental phenotypic transformation of both sexual and asexual taxa occurs rapidly, in comparatively large populations, and is accompanied by a significant elevation of phenotypic variance. This increase in variance reflects extreme developmental instability in the transitional populations.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on Springer Link
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Leakey, R.E.F. & Leakey, M. (eds) Koobi Fora Research Project Monographs 1 (Clarendon, Oxford, 1978).
Vondra, C. F. & Bowen, B. E. in Geological Background to Fossil Man (ed. Bishop, W. W.) (Scottish Academic, Edinburgh, 1978).
Isaac, G. Ll. in Earliest Man and Environments in the Lake Rudolf Basin (eds Coppens, Y., Clark Howell, F., Isaac, G. Ll. & Leakey, R. E. F.) (University of Chicago Press, 1976).
Harris, J. M. in Koobi Fora Research Project Monographs 1 (eds Leakey, R. E. F. & Leakey, M.) (Clarendon, Oxford, 1978).
Raup, D. M. J. Paleont. 40, 1178–1190 (1966).
Findlater, I. C. in Geological Background to Fossil Man (ed. Bishop, W. W.) (Scottish Academic, Edinburgh, 1978).
White, T. D. & Harris, J. M. Science 198, 13–21 (1977).
Harris, J. M. & White, T. D. Trans. Am. phil. Soc. 69, 1–128 (1979).
Simpson, G. G., Roe, A. & Lewontin, R. C. Quantitative Zoology (Academic, New York, 1960).
Williamson, P. G. thesis, Univ. Bristol (1980).
Johnson, G. D. & Raynolds, R. G. H. in Earliest Man and Environments in the Lake Rudolf Basin (eds Coppens, Y., Clark Howell, F., Isaac, G. Ll. & Leakey, R. E. F.) (University of Chicago Press, 1976).
Findlater, I. C. in Koobi Fora Research Project Monographs 1 (eds Leakey, R. E. F. & Leakey, M.) (Clarendon, Oxford, 1978).
Abell, P. I., Awramik, S. M., Osborne, R. H. & Tomellini, S. Sediment Geol. (in the press).
Cerling, T. E. Palaeogeogr. Palaeoclimatol. Palaeoecol. 27, 247–285 (1979).
Brooks, J. L. Q. Rev. Biol. 25, 132–176 (1950).
Gould, S. J. & Eldredge, N. Paleobiology 3, 115–151 (1977).
Eldredge, N. & Gould, S. J. in Models in Paleobiology (ed. Schopf, T. J. M.) 82–115 (Freeman, Cooper, San Francisco, 1972).
Hallam, A. Nature 258, 439–446 (1975).
Gould, S. J. & Eldredge, N. Paleobiology 3, 115–151 (1977).
Stanley, S. M. Macroevolution (Freeman, San Francisco, 1979).
Mayr, E. in Evolution as a Process (eds Huxley, J., Hardy, A. C. & Ford, E. B.) 157–180 (1954).
Gingerich, P.D. Am. J. Sci. 276, 1–28 (1976).
Kellog, D. E. Paleobiology 1, 150–160 (1975).
Ovcharenko, V. N. Palaeont. J. 57, 57–63 (1969).
Lande, R. Am. Nat. 116, 463–479 (1980).
Templeton, A. R. Evolution 34, 719–729 (1980).
Templeton, A. R. Genetics 94, 1011–1020 (1980).
Levins, D. A. Am. Nat. 104, 343–353 (1970).
Carson, M. L. Am. Nat. 109, 83–92 (1975).
Jacob, J. Trans. R. Soc. Edinb. 63, 341–352 (1957).
Jacob, J. Trans. R. Soc. Edinb. 64, 433–444 (1958).
Starmühlner, F. Malacologia 8, 1–434 (1969).
Mandahl-Barth, G. Field Guide to African Freshwater Snails, 2 (WHO Snail Identification Centre, Danish Bilharziasis Laboratory, 1973).
Enrlich, P. R. & Raven, P. H. Science 165, 1228–1232 (1969).
Barnes, C. & Kearsey, A. L. Heredity 25, 1–21 (1970).
Walker, B. W. Calif. Fish Game 113, 104–151 (1961).
Gould, S. J. Paleobiology 6, 119–130 (1980).
Fitch, F. J. & Miller, J. A. in Earliest Man and Environments in the Lake Rudolf Basin (eds Coppens, Y., Clark Howell, F., Isaac, G. Ll. & Leakey, R. E. F.) (University of Chicago Press, 1976).
Brock, A. & Isaac, G. Ll. in Earliest Man and Environments in the Lake Rudolf Basin (eds Coppens, Y., Clark Howell, F., Isaac, G. Ll. & Leakey, R. E. F.) (University of Chicago Press, Chicago, 1976).
Hillhouse, J. W., Ndombi, J. W. M., Cox, A. & Brock, A. Nature 265, 411–415 (1977).
Curtis, G. H., Drake, S., Cerling, T. & Hampel, J. Nature 258, 395–398 (1975).
Hay, R. L. Nature 284, 401 (1980).
Fuchs, V. E. Phil. Trans. R. Soc. B229, 219–274 (1939).
Watkins, R. & Williamson, P. G. Proc. 8th Pan-African Congress of Prehistory and Quaternary Studies (1979).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Williamson, P. Palaeontological documentation of speciation in Cenozoic molluscs from Turkana Basin. Nature 293, 437–443 (1981). https://doi.org/10.1038/293437a0
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1038/293437a0
This article is cited by
-
Adaptive divergence in shell morphology in an ongoing gastropod radiation from Lake Malawi
BMC Evolutionary Biology (2020)
-
Modules and Mosaics in the Evolution of the Tetonius – Pseudotetonius Dentition
Journal of Mammalian Evolution (2020)
-
Phylogeography of Bellamya (Mollusca: Gastropoda: Viviparidae) snails on different continents: contrasting patterns of diversification in China and East Africa
BMC Evolutionary Biology (2019)
-
Preface: Speciation research in ancient lakes – classic concepts and new approaches
Hydrobiologia (2014)
Comments
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.