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Brachiopod outline and the importance of the logarithmic spiral

Published online by Cambridge University Press:  20 May 2016

Anthony E. Aldridge
Anthony E. Aldridge*
Affiliation:
Post Office Box 4050, St. Kilda, Dunedin, New Zealand. E-mail: tonya@deepsouth.co.nz
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Abstract

To a first approximation, the logarithmic spiral is a close fit to the biconvex lateral outline of three terebratellid genera from Australasia. Investigation of spiral parameters confirms the value of the biconvex morphospace of McGhee (1980), but not the method for estimating the spiral itself. Deviations from the estimated spiral are episodic and consistent with Rudwick's (1959) observations of allometry in brachiopod growth. Morphospace location is postulated to be indicative of a species' substrate and lifestyle. The logarithmic spiral offers much opportunity for gaining better understanding of external shape and its cause in articulate brachiopods.

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Type
Articles
Information
Paleobiology , Volume 24 , Issue 2 , Spring 1998 , pp. 215 - 226
Copyright
Copyright © The Paleontological Society 

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References

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