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Pattern of growth rate around aperture and shell form in Bivalvia: a theoretical morphological study

Published online by Cambridge University Press:  08 April 2016

Takao Ubukata
Takao Ubukata*
Affiliation:
Institute of Geosciences, Shizuoka University, Oya 836, Shizuoka 422–8529, Japan. E-mail: sbtubuk@ipc.shizuoka.ac.jp
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Abstract

Shell growth and morphogenesis were studied in nine species of Bivalvia from the viewpoint of theoretical morphology. The aperture map, or pattern of relative rate of shell accretion for each point around the aperture, received particular attention. Morphometric analyses indicate that the basic pattern of the aperture map is generally maintained throughout ontogeny, whereas both shell convexity and aperture shape commonly change with growth. Computer simulations show that posterior elongation of the aperture with growth cancels the effect of ontogenetic shell inflation to move the maximal growth point anteriorly. In the species examined, the coiling axis is generally inclined to the hinge axis toward the anterodorsal direction and is plunging to the dextral side of the valve. This condition allows ontogenetic shell inflation without modification of the basic pattern of the aperture map. The result indicates that ontogenetic change of shell form is architecturally constrained by a basic pattern of the aperture map, which is kept throughout ontogeny.

Type
Articles
Information
Paleobiology , Volume 29 , Issue 4 , Fall 2003 , pp. 480 - 491
Copyright
Copyright © The Paleontological Society 

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References

Literature Cited

Ackerly, S. C. 1989. Kinematics of accetionary shell growth, with examples from brachiopods and molluscs. Paleobiology 4:374–378.Google Scholar
Bayer, U. 1978. Morphologenetic programs, instabilities, and evolution: a theoretical study. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 156:226–261.Google Scholar
Checa, A. 1991. Sectorial expansion and shell morphogenesis in Mollusca. Lethaia 24:97–114.CrossRefGoogle Scholar
Checa, A., and Aguado, R. 1992. Sectorial-expansion analysis of irregularly coiled shells; application to the recent gastropod Distorsio. Palaeontology 35:913–925.Google Scholar
Cortie, M. B. 1989. Models for mollusk shape. South African Journal of Science 85:454–460.Google Scholar
Gould, S. J., and Vrba, E. S. 1982. Exaptation: a missing term in the science of form. Paleobiology 8:4–15.Google Scholar
Hutchinson, J. M. C. 1990. Control of gastropod shell form via apertural growth rates. Journal of Morphology 206:259–264.Google Scholar
L⊘vtrup, S., and von Sydow, B. 1974. D'Arcy Thompson's theorems and the shape of the molluscan shell. Bulletin of Mathematical Biology 36:567–575.Google Scholar
McGhee, G. R. Jr. 1978. Analysis of the shell torsion phenomenon on the Bivalvia. Lethaia 11:315–329.Google Scholar
McGhee, G. R. Jr. 1980. Shell form in the biconvex articulate Brachiopoda: a geometric analysis. Paleobiology 6:57–76.Google Scholar
Morita, R. 1991. Mechanical constraints on aperture form in Gastropods. Journal of Morphology 207:93–102.Google Scholar
Okamoto, T. 1988. Analysis of heteromorph ammonoids by differential geometry. Palaeontology 31:35–52.Google Scholar
Raup, D. M. 1966. Geometric analysis of shell coiling: general problems. Journal of Paleontology 40:1178–1190.Google Scholar
Rice, S. H. 1998. The bio-geometry of mollusc shells. Paleobiology 24:133–149.Google Scholar
Savazzi, E. 1985. SHELLGEN, a BASIC program for the modeling of molluscan shell ontogeny and morphogenesis. Computer and Geoscience 11:521–530.Google Scholar
Savazzi, E. 1987. Geometric and functional constraints on bivalve shell morphology. Lethaia 20:293–306.Google Scholar
Seilacher, A. 1970. Arbeitskonzept zur Konstruktions-Morphologie. Lethaia 3:393–396.Google Scholar
Stanley, S. M. 1975. Why clams have the shape they have: an experimental analysis of burrowing. Paleobiology 1:48–58.Google Scholar
Stone, J. R. 1995. CerioShell: a computer program designed to simulate variation in shell form. Paleobiology 21:509–519.Google Scholar
Ubukata, T. 2000. Theoretical morphology of hinge and shell form in Bivalvia: geometric constraints derived from space conflict between umbones. Paleobiology 26:606–624.Google Scholar
Ubukata, T. 2001. Morphological significance of the orientation of shell coiling and the outline of aperture in bivalve molluscs. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 221:249–270.Google Scholar
Ubukata, T. 2002. Stacking increments: a new model and morphospace for the analysis of bivalve shell growth. Historical Biology 15:303–321.Google Scholar
Ubukata, T., and Nakagawa, Y. 2000. On the origin of peculiar sculptural pattern of the Cretaceous bivalve Inoceramus hobetsensis. Lethaia 33:313–329.Google Scholar