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Prolonged stability in local populations of Cerion agassizi (Pleistocene-Recent) on Great Bahama Bank

Published online by Cambridge University Press:  08 April 2016

Stephen Jay Gould*
Affiliation:
Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts 02138

Abstract

Long-term persistence of patterns in geographic variation within species is an interesting and puzzling phenomenon. I present a well-defined natural experiment in the land snail Cerion agassizi from the islands of Great Bahama Bank. C. agassizi is the best-known fossil of the ca. 120,000 years BP dunes of New Providence, Cat and Eleuthera Islands; populations have survived on Cat and Eleuthera. During the Wisconsin glacial advance, all these islands joined together in an emergent bank. Presence of the same species on two islands at two times permits a test for both time signatures (does change occur in the same manner on both islands) and island signatures (do aspects of shell phenotypes remain constant on each island through time).

Factor and discriminant analyses establish morphological separations among fossil populations of the three islands. These differences occur along pathways specified by well-known covariance sets in the complex allometric ontogeny of Cerion. By these routes, small variations in the geometry of growth may be magnified to large differences in external appearance. I found a time signature, probably attributable to introgression of modern populations by Cerion glans on both Cat and Eleuthera. Despite the intermediate period of emergence and joining of all islands, I also found an island signature in the preservation through time, on both Cat and Eleuthera, of the differentia that separate fossil populations. The basic distinctions of the two islands, expressed as patterns of covariance in growth, have been stable for at least 120,000 years.

Type
Articles
Copyright
Copyright © The Paleontological Society 

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References

Literature Cited

Beach, D. K. and Ginsburg, R. N. 1980. Facies succession of Plio-Pleistocene carbonates, Northwestern Great Bahama Bank. Bulletin of the American Association of Geologists 64:16341642.Google Scholar
Cain, A. J. and Currey, I. D. 1963. Area effects in Cepaea. Philosophical Transactions of the Royal Society of London 246:181.Google Scholar
Cann, R. L., Stoneking, M., and Wilson, A. C. 1987. Mitochondrial DNA and human evolution. Nature 325:3136.Google Scholar
Cheetham, A. H. 1986. Tempo of evolution in a Neogene bryozoan: rates of morphologic change within and across species boundaries. Paleobiology 12:190202.CrossRefGoogle Scholar
Clench, W. J. 1957. A catalogue of the Cerionidae (Mollusca—Pulmonata). Bulletin of the Museum of Comparative Zoology 116:121169.Google Scholar
Currey, J. D. and Cain, A. J. 1968. Studies in Cepaea IV: climate and selection of banding morphs in Cepaea from the climatic optimum to the present day. Philosophical Transactions of the Royal Society of London 253:483498.Google Scholar
Dall, W. H. 1894. Cruise of the steam yacht “Wild Duck” in the Bahamas, January to April, 1893, in charge of Alexander Agassiz. II. Notes on the shells collected. Bulletin of the Museum of Comparative Zoology 25:113123.Google Scholar
Diver, C. 1929. Fossil record of Mendelian mutants. Nature 124:183.CrossRefGoogle Scholar
Eldredge, N. and Gould, S. J. 1972. Punctuated equilibria: an alternative to phyletic gradualism. Pp. 82115. In Schopf, T. J. M. (ed.), Models in Paleobiology. Freeman, Cooper and Co., San Francisco, CA.Google Scholar
Garrett, P. and Gould, S. J. 1984. Geology of New Providence Island, Bahamas. Geological Society of America Bulletin 95:209220.Google Scholar
Gibbs, H. L. and Grant, P. R. 1987. Oscillating selection on Darwin's finches. Nature 327:511513.CrossRefGoogle Scholar
Goodhart, C. B. 1963. Area effects and non-adaptive variation between populations of Cepaea (Mollusca). Heredity 18:459465.Google Scholar
Goodhart, C. B. 1987. Why are some snails visibly polymorphic and others not? Biological Journal of the Linnean Society 31:3557.CrossRefGoogle Scholar
Gould, S. J. 1969a. An evolutionary microcosm: Pleistocene and Recent history of the land snail P. (Poecilozonites) in Bermuda. Bulletin of the Museum of Comparative Zoology 138:407532.Google Scholar
Gould, S. J. 1969b. Character variation in two land snails from the Dutch Leeward Islands: geography, environment, and evolution. Systematic Zoology 18:185200.Google Scholar
Gould, S. J. 1977. Ontogeny and Phylogeny. Harvard University Press, Cambridge, Massachusetts. 501 pp.Google Scholar
Gould, S. J. 1984a. Covariance sets and ordered geographic variation in Cerion from Aruba, Bonaire, and Curaçao: a way of studying nonadaptation. Systematic Zoology 33:217237.Google Scholar
Gould, S. J. 1984b. Morphological channeling by structural constraint: convergence in styles of dwarfing and gigantism in Cerion, with a description of two new fossil species and a report on the discovery of the largest Cerion. Paleobiology 10:172194.CrossRefGoogle Scholar
Gould, S. J. and Paull, C. 1977. Natural history of Cerion. VII. Geographic variation of Cerion (Mollusca: Pulmonata) from the eastern end of its range (Hispaniola to the Virgin Islands): coherent patterns and taxonomic simplification. Museum of Comparative Zoology, Breviora no. 445. 24 pp.Google Scholar
Gould, S. J. and Woodruff, D. S. 1978. Natural history of Cerion. VIII. Little Bahama Bank—a revision based on genetics, morphometrics, and geographic distribution. Bulletin of the Museum of Comparative Zoology 148:371415.Google Scholar
Gould, S. J. and Woodruff, D. S. 1986. Evolution and systematics of Cerion (Mollusca: Pulmonata) on New Providence Island: a radical revision. Bulletin of the American Museum of Natural History 182:389490.Google Scholar
Gould, S. J. and Woodruff, D. S. 1987. Systematics and levels of covariation in Cerion from the Turks and Caicos Islands. Bulletin of the Museum of Comparative Zoology.Google Scholar
Gould, S. J., Woodruff, D. S., and Martin, J. P. 1974. Genetics and morphometrics of Cerion at Pongo Carpet: a new systematic approach to this enigmatic land snail. Systematic Zoology 23:518535.CrossRefGoogle Scholar
Johnston, R. F. and Selander, R. K. 1964. House sparrows: rapid evolution of races in North America. Science 144:548550.Google Scholar
Land, L. S. 1967. Diagenesis of skeletal carbonates. Journal of Sedimentary Petrology 37:914930.Google Scholar
Land, L. S., Mackenzie, F. T., and Gould, S. J. 1967. Pleistocene history of Bermuda. Geological Society of America Bulletin 78:9931006.CrossRefGoogle Scholar
Maynard, C. S. 1889. Monograph of the genus Strophia. Contributions to Science, 1, Newtonville, Massachusetts.Google Scholar
Owen, D. F. 1963. Polymorphism in living and Pleistocene populations of the African land snail Limicolaria martensiana. Nature 199:713714.Google Scholar
Owen, D. F. 1966. Polymorphism in Pleistocene land snails. Science 152:7172.Google Scholar
Raff, R. A. and Kaufman, T. C. 1983. Embryos, Genes, and Evolution. Macmillan, New York. 395 pp.Google Scholar
Seger, J. 1987. El Niño and Darwin's finches. Nature 327:461.Google Scholar
Stanley, S. M. and Yang, X. 1987. Approximate evolutionary stasis for bivalve morphology over millions of years: a multivariate, multilineage study. Paleobiology 13:113139.CrossRefGoogle Scholar
Wilson, E. O. and Brown, W. L. 1953. The subspecies concept and its taxonomic applications. Systematic Zoology 2:97111.Google Scholar
Woodruff, D. S. and Gould, S. J. 1987. Fifty years of intraspecific hybridization in Cerion: genetics and morphometrics of a controlled experiment on the land snail Cerion in the Florida Keys. Evolution 41:10221045.Google Scholar