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The relationship of trabecular architecture to inferred loading patterns in the third metacarpals of the extinct equids Merychippus and Mesohippus

Published online by Cambridge University Press:  08 February 2016

J. J. Thomason*
Affiliation:
Department of Vertebrate Palaeontology, Royal Ontario Museum, 100 Queens Park, Toronto, Ontario M5S 2C6, Canada Department of Zoology, University of Toronto, Toronto, Ontario, M5S 1A1, Canada

Abstract

The internal structures of the third metacarpals of Merychippus and Mesohippus are assessed from thin sections and from radiographs, and systems of trabeculae differing in orientation and density are described. The principal forces transmitted to the articular surfaces of these bones are reconstructed and are used to estimate the pressure of contact on each surface. The major correlations made between the structure and the function of the third metacarpal of Equus (Thomason, 1985a) are also observed in this bone in Merychippus and Mesohippus. More important, the differences in trabecular structure among the recent and fossil bones may be interpreted in terms of the differences in inferred function. Thus the functional interpretation of the internal structure of fossil bones may reasonably be attempted.

Type
Research Article
Copyright
Copyright © The Paleontological Society 

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References

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