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Estimating numbers of whole individuals from collections of body parts: a taphonomic limitation of the paleontological record

Published online by Cambridge University Press:  08 February 2016

Norman L. Gilinsky
Affiliation:
Department of Geological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
J Bret Bennington
Affiliation:
Department of Geological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061

Abstract

Paleoecologists have long sought to obtain estimates of the sizes of extinct populations. However, even in ideal cases, accurate counts of individuals have been hampered by the fact that many organisms disarticulate after death and leave their remains in the form of multiple, separated parts. We here analyze the problem of estimating numbers of individuals from collections of parts by developing a general counting theory that elucidates the major contributing variables. We discover that the number of unique individuals of a particular species that are represented in a fossil collection can be described by an intricate set of relationships among (1) the number of body parts that were recovered, (2) the number of body parts that were possessed by organisms belonging to that species, and (3) the number of individuals of that species that served as the source of the parts from which the paleontological sample was obtained (the size of the “sampling domain”). The “minimum number of individuals” and “maximum number of individuals” methods currently used by paleontologists to count individuals emerge as end members in our more general counting theory. The theory shows that the numbers of individuals of a species that are represented in a sample of body parts is fully tractable, at least in a theoretical sense, in terms of the variables just mentioned. The bad news is that the size of the “sampling domain” for a species can never be known exactly, thus placing a very real limit on our ability to count individuals rigorously. The good news is that one can often make a reasonable guess regarding the size of the sampling domain, and can therefore make a more thoroughly informed choice regarding how to estimate numbers of individuals. By isolating the variables involved in determining the numbers of individuals in paleontological samples, we are led to a better appreciation of the limits, and the possibilities, that are inherent in the fossil record.

Type
Articles
Copyright
Copyright © The Paleontological Society 

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References

Literature Cited

Badgely, C. E. 1986. Taphonomy of mammalian fossil remains from Siwalik rocks of Pakistan. Paleobiology 12:119142.CrossRefGoogle Scholar
Behrensmeyer, A. K. 1991. Terrestrial vertebrate accumulations. Pp. 291335in Allison, P. A. and Briggs, D. E. G., eds. Taphonomy: releasing the data locked in the fossil record. Plenum, New York.CrossRefGoogle Scholar
Brett, C. E., and Baird, G. C. 1986. Comparative taphonomy: a key to paleoenvironmental interpretation based on fossil preservation. Palaios 1:207227.CrossRefGoogle Scholar
Efremov, J. A. 1940. Taphonomy: a new branch of paleontology. Pan-American Geologist 74:8193.Google Scholar
Hallam, A. 1972. Models involving population dynamics. Pp. 6280in Schopf, T. J. M., ed. Models in paleobiology. Freeman, Cooper, San Francisco.Google Scholar
Heck, K. L. Jr., Van Belle, G., and Simberloff, D. S. 1975. Explicit calculation of the rarefaction diversity measurement and the determination of sufficient sample size. Ecology 56:14591461.CrossRefGoogle Scholar
Holtzman, R. C. 1979. Maximum likelihood estimation of fossil assemblage composition. Paleobiology 5:7789.CrossRefGoogle Scholar
Hurlbert, S. H. 1971. The nonconcept of species diversity: a critique and alternative parameters. Ecology 52:577586.CrossRefGoogle ScholarPubMed
Kidwell, S. M., and Bosence, D. W. J. 1991. Taphonomy and time-averaging of marine shelly faunas. Pp. 116209in Allison, P. A. and Briggs, D. E. G., eds. Taphonomy: releasing the data locked in the fossil record. Plenum, New York.Google Scholar
Klein, R. G. 1980. The interpretation of mammalian faunas from stone-age archeological sites, with special reference to sites in the Southern Cape Province, South Africa. Pp. 223246in Behrensmeyer, A. K. and Hill, A. P., eds. Fossils in the making: vertebrate taphonomy and paleoecology. University of Chicago Press.Google Scholar
Miller, A. I., Llewellyn, G., Parsons, K. M., Cummins, H., Boardman, M. R., Greenstein, B. J., and Jacobs, D. K. 1992. Effect of Hurricane Hugo on molluscan skeletal distributions, Salt River Bay, St. Croix, U. S. Virgin Islands. Geology 20:2326.Google Scholar
Parsons, K. M., and Brett, C. E. 1991. Taphonomic processes and biases in modern marine environments: an actualistic perspective on fossil assemblage preservation. Pp. 2265in Donovan, S. K., ed. The processes of fossilization. Columbia University Press, New York.Google Scholar
Sanders, H. L. 1968. Marine benthic diversity: a comparative study. American Naturalist 102:243282.CrossRefGoogle Scholar
Shipman, P. 1981. Life history of a fossil. Harvard University Press, Cambridge.Google Scholar
Simberloff, D. S. 1974. Permo-Triassic extinctions: effects of area on biotic equilibrium. Journal of Geology 82:267274.CrossRefGoogle Scholar