Hostname: page-component-76d6cb85b7-92wsb Total loading time: 0 Render date: 2026-07-12T23:39:05.577Z Has data issue: false hasContentIssue false
  • English
  • Français

Finite-element analysis of simulated ammonoid septa (extinct Cephalopoda): septal and sutural complexities do not reduce strength

Published online by Cambridge University Press:  08 February 2016

Marwan A. Hassan ,
Gerd E. G. Westermann ,
Roger A. Hewitt  and
Mohamed A. Dokainish
Marwan A. Hassan
Affiliation:
Department of Mechanical Engineering, McMaster University, Hamilton, Ontario L8S 4M1, Canada
Gerd E. G. Westermann
Affiliation:
School of Geography and Geology, McMaster University, Hamilton, Ontario L8S 4M1, Canada
Roger A. Hewitt
Affiliation:
12 Fairfield Road, Eastwood, Leigh-on-Sea, Essex SS9 5SB, United Kingdom
Mohamed A. Dokainish
Affiliation:
Department of Mechanical Engineering, McMaster University, Hamilton, Ontario L8S 4M1, Canada
Get access Rights & Permissions [Opens in a new window]

Abstract

Finite-element analysis of circular septum models indicates that (1) anticlastic fluting weakened the last septa of the same radius of curvature by a factor of about 2.5 relative to the tensile stresses in a sphere of nacre, (2) septa with ammonitic sutures were stronger than those with goniatitic sutures of the same thickness, and (3) septa with more “complex” ammonitic sutures were stronger at the edge between lobes and saddles than “simple” ones. These results contradict recent claims that ammonoid septa became weaker as sutural complexity increased from goniatitic through ammonitic, so that the most complex sutures were limited to the shallowest habitats. The smaller marginal flutes of complex septa were relatively strong, allowing them to be thinner than the central septum and still act as elastic wall supports. Many Mesozoic ammonoids with highly sinuous sutures occurred in deep epeiric and open-ocean habitats, whereas it is those with secondarily reduced, ceratitic sutures that were typically associated with restricted shallow basins.

Information

Type
Articles
Information
Paleobiology , Volume 28 , Issue 1 , Winter 2002 , pp. 113 - 126
Copyright
Copyright © The Paleontological Society 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Article purchase

Temporarily unavailable

References

Literature Cited

Batt, R. J. 1991. Sutural amplitude of ammonite shells as a paleoenvironmental indicator. Lethaia 24:219–225.CrossRefGoogle Scholar
Chamberlain, J. A., and Chamberlain, R. B. 1986. Is cephalopod septal strength index an index of septal complexity? Alcheringa 10:85–97.CrossRefGoogle Scholar
Daniel, Th. L., Helmuth, B. S., Saunders, W. B., and Ward, P. D. 1997. Septal complexity in ammonoid cephalopods increased mechanical risk and limited depth. Paleobiology 23:470–481.CrossRefGoogle Scholar
Dokainish, M. A. 1988. Incremental Nonlinear Dynamic Analysis Program: verification manual. INDAP manual. McMaster University, Canada.Google Scholar
Hewitt, R. A. 1996. Architecture and strength of the ammonoid shell. Pp. 297–339in Landman, N. H., Tanabe, K., and Davis, R. A., eds. Ammonoid paleobiology. Plenum, New York.CrossRefGoogle Scholar
Hewitt, R. A. 1999. Variation in the tensile strength of nacreous septa. Pp. 355–362in Savazzi, E., ed. Functional morphology of the invertebrate skeleton. Wiley, Chichester, England.Google Scholar
Hewitt, R. A. 2000 Geological interpretations from cephalopod habitat and implosion depth limits. Revue de Paleobiologie Special Volume 8:95–107.Google Scholar
Hewitt, R. A., and Westermann, G. E. G. 1987a. Nautilus shell architecture. Pp. 435–461in Saunders, W. B. and Landman, N. H., eds. The biology and paleobiology of a living fossil. Plenum, New York.CrossRefGoogle Scholar
Hewitt, R. A., and Westermann, G. E. G. 1987b. Functions of complexly fluted septa in ammonoid shells II. Septa evolution and conclusions. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 174:135–169.Google Scholar
Hewitt, R. A., and Westermann, G. E. G. 1997. Mechanical significance of ammonoid septa with complex sutures. Lethaia 30:205–212.CrossRefGoogle Scholar
Hewitt, R. A., Dokainish, M. A., El Aghoury, M., and Westermann, G. E. G. 1989. Bathymetric limits of a Carboniferous orthoconic nautiloid deduced by finite element analysis. Palaios 3:157–167.CrossRefGoogle Scholar
Hewitt, R. A., Abdelsalam, U. A., Dokainish, M. A., and Westermann, G. E. G. 1993. Comparison of the relative strength of siphuncles with prochoanitic and retrochoanitic septal necks by finite element analysis. In House, M. R., ed. The Ammonoidea: environment, ecology and evolutionary change. Systematic Association Special Volume 47:85–98. Clarendon, Oxford.Google Scholar
Jacobs, D. 1990. Sutural pattern and shell strength in Baculites with implications for other cephalopod shell morphologies. Paleobiology 16:336–348.CrossRefGoogle Scholar
Jacobs, D. 1992. The support of hydrostatic load in cephalopod shells: adaptive and ontogenetic explanations of shell form and evolution from Hook 1695 to the present. Pp. 287–349in Hecht, M. K., Wallace, B., and MacIntyre, R. J., eds. Evolutionary biology. Plenum, New York.CrossRefGoogle Scholar
Jacobs, D. 1996. Chambered cephalopod shells, buoyancy, structure and decoupling: history and red herrings. Palaios 11:610–614.CrossRefGoogle Scholar
Pfaff, E. 1911. Über Form und Bau der Ammonitensepten und ihre Beziehungen zur Suturlinie. Jahrbuch des Niedersächischen Geologischen Vereins Hannover 1911:207–223. Hannover.Google Scholar
Saunders, W. B., and Ward, P. D. 1987. Ecology, distribution, and population characteristics of Nautilus. Pp. 137–162in Saunders, W. B. and Landman, N. H., eds. Nautilus: the biology and paleobiology of a living fossil. Plenum, New York.CrossRefGoogle Scholar
Saunders, W. B., and Work, D. M. 1995. Shell morphology and suture complexity in Upper Carboniferous ammonoids. Paleobiology 22:189–218.CrossRefGoogle Scholar
Saunders, W. B., Work, D. M., and Nikolaeva, S. V. 1999. Evolution of complexity in Paleozoic ammonoid sutures. Science 286:760–763.CrossRefGoogle ScholarPubMed
Seilacher, A. 1988. Why are nautiloids and ammonites so different? Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 77:41–69.Google Scholar
Teichert, K. 1964. Actinoceratoidea. Pp. K190–K216in Stenzel, H. B. et al. Mollusca 3, Cephalopoda, Nautiloidea. Part K ofMoore, R. C., ed. Treatise on invertebrate paleontology. Geological Society of America, New York, and University of Kansas, Lawrence.Google Scholar
Ulrich, M., and Mundlos, R. 1985. Immigration of cephalopods into the German Muschelkalk basin and its influence on the suture lines. Pp. 221–239in Bayer, U. and Seilacher, A., eds. Sedimentary and evolutionary cycles: lecture notes in earth sciences. Springer, Berlin.Google Scholar
Wang, Y., and Westermann, G. E. G. 1993. Paleoecology of Triassic ammonoids. Geobios Mémoire Spécial 15:373–392.CrossRefGoogle Scholar
Westermann, G. E. G. 1956. Phylogenie der Stephanocerataceae und Perisphinctaceae des Dogger. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 103:233–279.Google Scholar
Westermann, G. E. G. 1971. Form, structure and function of shell and siphuncle in coiled Mesozoic ammonoids. Life Sciences Contributions, Royal Ontario Museum 78:1–39.Google Scholar
Westermann, G. E. G. 1973. Strength of concave septa and depth limits of fossil cephalopods. Lethaia 6:383–403.CrossRefGoogle Scholar
Westermann, G. E. G. 1975. Model for origin, function and fabrication of fluted cephalopod septa. Paläontologische Zeitschrift 49:235–253.CrossRefGoogle Scholar
Westermann, G. E. G. 1977. Form and function of orthoconic cephalopods with concave septa. Paleobiology 3:300–321.CrossRefGoogle Scholar
Westermann, G. E. G. 1996. Ammonoid life and habitat. Pp. 608–707in Landman, N., Tanabe, K., and Davis, R., eds. Ammonoid paleobiology. Plenum, New York.Google Scholar
Westermann, G. E. G. 1999. Life habits of nautiloids. Pp. 263–298in Savazzi, E., ed. Functional morphology of the invertebrate skeleton. Wiley, Chichester, England.Google Scholar