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Why clams have the shape they have: an experimental analysis of burrowing

Published online by Cambridge University Press:  08 April 2016

Steven M. Stanley
Steven M. Stanley*
Affiliation:
Department of Earth and Planetary Sciences, The Johns Hopkins University, Baltimore, Maryland 21218
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Abstract

The prosogyrous shape and flattened lunule of a typical clam shell form a blunt anterior, the function of which is related to the forward-and-back rocking motion of the shell in burrowing. Analysis of movies has revealed that each rocking motion of a morphologically typical clam, Mercenaria mercenaria (Linné), involves purely rotational movement, with no translational component. The clam is able to burrow by “walking” its way downward only because the axis of backward rotation lies to the anterior of the axis of forward rotation. Experiments with burrowing robots show that the blunt anterior serves to shift the axis of backward rotation anteriorly, thus aiding in downward progress. The prosogyrous condition and the rotational mechanism of burrowing are fundamental adaptations of burrowing clams and were apparently present in the ancestral bivalves of the Cambrian.

Type
Research Article
Information
Paleobiology , Volume 1 , Issue 1 , Winter 1975 , pp. 48 - 58
Copyright
Copyright © The Paleontological Society 

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References

Literature Cited

Ansell, A. D. 1961. The functional morphology of the British species of Veneracea (Eulamellibranchia). J. Mar. Biol. Ass. U. K. 41:489–515.Google Scholar
Carter, R. M. 1967. On the nature and definition of the lunule, escutcheon and corcelet in the Bivalvia. Proc. Malacol. Soc. London. 37:243–263.Google Scholar
Harry, H. W. 1973. Neglected topographical relationships between the gill and shell of bivalve mollusks. Bull. Amer. Malacological Union. March issue:23–24.Google Scholar
Mann, H. B., and Whitney, D. R. 1947. On a test of whether one of two random variables is stochastically larger than the other. Ann. Math. Statist. 18:52–54.CrossRefGoogle Scholar
Pojeta, J., Runnegar, B., and Kriz, J. 1973. Fordilla troyensis Barrande: the oldest known pelecypod. Science. 180:866–868.CrossRefGoogle ScholarPubMed
Pojeta, J., Runnegar, B., Morris, N. J., and Newell, N. D. 1972. Rostroconchia: a new class of bivalved mollusks. Science. 177:264–267.Google Scholar
Stanley, S. M. 1969. Bivalve mollusk burrowing aided by discordant shell ornamentation. Science. 166:634–635.CrossRefGoogle ScholarPubMed
Stanley, S. M. 1970. Relation of shell form to life habits of the Bivalvia. Geol. Soc. Amer. Mem. 125. 296 pp.Google Scholar
Stanley, S. M. in press. Adaptive themes in the evolution of the Bivalvia (Mollusca). Ann. Rev. Earth and Plant. Sci., vol. 3.Google Scholar
Trueman, E. R. 1966. Bivalve mollusks: Fluid dynamics of burrowing. Science. 152:523–525.Google Scholar