Hostname: page-component-8448b6f56d-cfpbc Total loading time: 0 Render date: 2024-04-24T16:50:24.465Z Has data issue: false hasContentIssue false

The function of the ammonite fluted septal margins

Published online by Cambridge University Press:  14 July 2015

Zeev Lewy*
Affiliation:
Geological Survey of Israel, 30 Malkhe Yisrael St., Jerusalem 95501, Israel

Abstract

The fluted margins of ammonite septa were thought to resist the hydrostatic pressure upon the phragmocone while the ammonoid dived. However, ammonoids probably did not dive deeper than the extant nautilids, whose conchs, with the simple septa, sustain pressure correlative to depth of about 800 m. The backward and forward stretching lobes and saddles actually provide resistance to pressure perpendicular to the septum. Ammonoids lived for about three to five years, and septa were precipitated in intervals of nearly two weeks to two days, which explain the small dimensions of the scars of the adductor muscles, which were periodically detached and reattached. The weak hold between these small muscles and the buoyant conch was compensated for by the backward branching and expanding folds (forming the sutural lobes), into which the soft tissue penetrated and stiffened for a required period to firmly anchor the body to the conch throughout its whole circumference. The greater the complexity of the septa marginal fluting, the better the ammonoid could withstand the dragging force between the body and the buoyant conch, and hence the more aggressively the ammonoid predated and competed with other creatures.

Type
Research Article
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.)

References

Batt, R. J. 1991. Sutural amplitude of ammonite shell as a paleoenvironmental indicator. Lethaia, 24:219225.CrossRefGoogle Scholar
Blind, W. 1975. Über die Entstehung und Funktion der Lobenlinie bei Ammonoideen. Paläontologische Zeitschrift, 49:254267.CrossRefGoogle Scholar
Blind, W. 1980. Über Anlage und Ausformung von Cephalopoden-Septen. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen, 160:217240.Google Scholar
Boutilier, R. G., West, T. G., Pogson, G. H., Mesa, K. A., Wells, J., and Wells, M. J. 1996. Nautilus and the art of metabolic maintenance. Nature, 382:534536.CrossRefGoogle Scholar
Bucher, H., Landman, N. H., Klofak, S. M., and Guex, J. 1996. Mode and rate of growth in ammonoids, p. 407461. In Landman, N. H., Tanabe, K., and Davis, R. A. (eds.), Ammonoid Paleobiology: Topics in Geobiology 13. Plenum Press, New York.CrossRefGoogle Scholar
Buckland, W. 1836. Geology and mineralogy considered with reference to natural theology. William Pickering, London, volume 1, 599 p.; volume 2, 128 p.CrossRefGoogle Scholar
Checa, A. G., and Garcia-Ruiz, J. M. 1996. Morphogenesis of the septum in ammonoids, p. 253296. In Landman, N. H., Tanabe, K., and Davis, R. A. (eds.), Ammonoid Paleobiology. Topics in Geobiology 13. Plenum Press, New York.CrossRefGoogle Scholar
Cobban, W. A., and Kennedy, W. J. 1993. The Upper Cretaceous dimorphic pachydiscid ammonite Menuites in the Western Interior of the United States. U.S. Geological Survey Professional Paper 1533, 14 p.Google Scholar
Daniel, T. L., Helmuth, B. S., Saunders, W. B., and Ward, P. D. 1997. Septal complexity in ammonoid cephalopods increased mechanical risk and limited depth. Paleobiology, 23:470481.CrossRefGoogle Scholar
Doguzhaeva, L., and Mutvei, H. 1996. Attachment of the body to the shell in ammonoids, p. 4363. In Landman, N. H., Tanabe, K., and Davis, R. A. (eds.), Ammonoid Paleobiology. Topics in Geobiology 13. Plenum Press, New York.CrossRefGoogle Scholar
Forsythe, J. W., and Hanlon, R. T. 1988. Behavior, body patterning and reproductive biology of Octopus bimaculoides from California. Malacologia, 29:4155.Google Scholar
Hanlon, R. T. 1988. Behavioral and body patterning characters useful in taxonomy and field identification of cephalopods. Malacologia, 29:247264.Google Scholar
Hartwick, B. 1983. Octopus dofleini, p. 277291. In Boyle, P. R. (ed.), Cephalopod Life Cycles. Academic Press, Oxford.Google Scholar
Heller, J. 1990. Longevity in molluscs. Malacologia, 31:259295.Google Scholar
Henderson, R. A. 1984. A muscle attachment proposal for septal function in Mesozoic ammonites. Palaeontology, 27:461486.Google Scholar
Hewitt, R. A., and Westermann, G. E. G. 1986. Function of complexly fluted septa in ammonoid shells, I., Mechanical principles and functional models. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen, 172:4769.Google Scholar
Hewitt, R. A., and Westermann, G. E. G. 1987. Function of complexly fluted septa in ammonoid shells. II. Septal evolution and conclusions. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen, 174:135169.Google Scholar
Hewitt, R. A., and Westermann, G. E. G. 1990. Nautilus shell strength variance as an indicator of habitat depth limits. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen, 179:7195.Google Scholar
Hewitt, R. A., and Westermann, G. E. G. 1997. Mechanical significance of ammonoid septa with complex sutures. Lethaia, 30:205212.CrossRefGoogle Scholar
Hewitt, R. A., Checa, A., Westermann, G. E. G., and Zaborski, P. M. 1991. Chamber growth in ammonites inferred from colour markings and naturally etched surfaces of Cretaceous vascoceratids from Nigeria. Lethaia, 24:271287.CrossRefGoogle Scholar
Hölder, H. 1952. Über Gehäusebau, insbesondere Hohlkiel jurassischer Ammoniten. Palaeontographica, Abteilung A, 102:1848.Google Scholar
Jordan, R. 1968. Zur Anatomie mesozoischer Ammoniten nach dem Strukturelementen der Gehäuse-Innenwand. Beihefte zum Geologischen Jahrbuch, 77:164.Google Scholar
Kanie, Y., Fukuda, Y., Nakayama, H., Seki, K., and Hattori, M. 1980. Impulsion of living Nautilus under increased pressure. Paleobiology, 6:4447.CrossRefGoogle Scholar
Kennedy, W. J., and Cobban, W. A. 1976. Aspects of ammonite biology, biogeography, and biostratigraphy. Special Papers in Palaeontology, 17:194.Google Scholar
Kennedy, W. J., and Kaplan, U. 1995. Parapuzosia (Parapuzosia) seppenradensis (Landois) und die Ammonitenfauna der Dülmener Schichten, unteres Unter-Campan, Westfalen. Geologie und Paläontologie in Westfalen, 33:1127.Google Scholar
Kennedy, W. J., Cobban, W. A., and Klinger, H. C. 1999. Muscle attachment and mantle-related features in Upper Cretaceous Baculites from the United States Western Interior. 5th International Symposium, Cephalopods—Present and Past. Vienna, Abstract volume 55.Google Scholar
Landman, N. H. 1985. Preserved ammonitellas of Scaphites (Ammonoidea. Ancyloceratina). American Museum Novitates, 2815:110.Google Scholar
Landman, N. H., Tanabe, K., Mapes, R. H., Klofak, S. M., and Whiehill, J. 1993. Pseudosutures in Paleozoic ammonoids. Lethaia, 26:99100.CrossRefGoogle Scholar
Landman, N. H., Lane, J., Cobban, W. A., Jorgensen, S. D., Kennedy, W. J., and Larson, N. L. 1999. Impressions of the attachment of the soft body to the shell in Late Cretaceous pachydiscid ammonites from the Western Interior of the United States. American Museum Novitates 3273, 31 p.Google Scholar
Lehmann, U. 1981. The ammonites; their life and their world. Cambridge University Press, Cambridge, 246 p.Google Scholar
Lewy, Z. 1996. Octopods: nude ammonoids that survived the Cretaceous-Tertiary mass extinction. Geology, 24:627630.2.3.CO;2>CrossRefGoogle Scholar
Lewy, Z., and Raab, M. 1978. Mid-Cretaceous stratigraphy of the Middle East. Annals du Museum d'Histoire Naturelle de Nice, Tome IV-1976:XXXII.120.Google Scholar
Miller, A. K., and Youngquist, W. 1946. A giant ammonite from the Cretaceous of Montana. Journal of Paleontology, 20:7375.Google Scholar
Moore, R. C. (ed.). 1964. Treatise on Invertebrate Paleontology, Pt. K, Mollusca 3. The Geological Society of America and The University of Kansas Press, 519 p.Google Scholar
Newell, N. D. 1949. Phyletic size increase, an important trend illustrated by fossil invertebrates. Evolution, 3:103124.CrossRefGoogle ScholarPubMed
O'dor, R. K., Forsythe, J., Webber, D. M., Wells, J., and Wells, M. J. 1993. Activity levels of Nautilus in the wild. Nature, 362:626628.CrossRefGoogle Scholar
Olóriz, F., and Palmqvist, P. 1995. Sutural complexity and bathymetry in ammonites: fact or artifact? Lethaia, 28:167170.Google Scholar
Olóriz, F., Palmqvist, P., and Pérez-Claros, J. A. 1999. Recent advances in morphometric approaches to covariation of shell features and the complexity of suture lines in Late Jurassic ammonites, with reference to the major environments colonized, p. 273293. In Olóriz, F. and Rodriguez-Tovar, F. J. (eds.), Advancing Research on Living and Fossil Cephalopods. Kluwer Academic/Plenum Publishers, New York.CrossRefGoogle Scholar
Packard, A., and Sanders, G. 1969. What the octopus shows to the world. Endeavour, 28(104):9299Google Scholar
Reyment, R. A. 1958. Some factors in the distribution of fossil cephalopods. Stockholm Contibutions to Geology, 1:97184.Google Scholar
Saunders, W. B. 1995. The ammonoid suture problem: relationships between shell and septum thickness and suture complexity in Paleozoic ammonoids. Paleobiology, 21:343355.CrossRefGoogle Scholar
Saunders, W. B., Work, D. M., and Nikolaeva, S. V. 1999. Evolution of complexity in Paleozoic ammonoid sutures. Science, 286:760763.CrossRefGoogle ScholarPubMed
Scott, G., and Moore, M. H. 1928. Ammonites of enormous size from the Texas Cretaceous. Journal of Paleontology, 2:273279.Google Scholar
Seilacher, A. 1975. Mechanische Simulation und funktionelle Evolution des Ammoniten-Septums. Paläontologische Zeitschrift, 49:268286.CrossRefGoogle Scholar
Spath, L. F. 1919. Notes on ammonites. Geological Magazine, 56:2735,65–71,115–122,170–177,220–225.CrossRefGoogle Scholar
Summesberger, H. 1979. Eine obersantone Ammonitenfauna aus dem Becken von Gosau (Oberösterreich). Annalen des Naturhistorischen Museums Wien, 82:109176.Google Scholar
Tanabe, K., Shigeta, Y., and Mapes, R. H. 1995. Early life history of Carboniferous ammonoids inferred from analysis of shell hydrostatics and fossil assemblages. Palaios, 10:8086.CrossRefGoogle Scholar
Voss, G. L. 1971. Shy monster, the octopus, (photo. R. F. Sisson). National Geographic, December 1971:776799.Google Scholar
Ward, P. D., and Westermann, G. E. G. 1976. Sutural inversion in a heteromorph ammonite and its implication for septal formation. Lethaia, 9:357361.CrossRefGoogle Scholar
Weitschat, W., and Bandel, K. 1991. Organic components in phragmocones of Boreal Triassic ammonoids: implications for ammonoid biology. Paläontologische Zeitschrift, 65:269303.CrossRefGoogle Scholar
Westermann, G. E. G. 1971. Form, structure and function of shell and siphuncle in coiled Mesozoic ammonoids. Life Science Contributions, Royal Ontario Museum, 78:139.Google Scholar
Westermann, G. E. G. 1975. Model for origin, function and fabrication of fluted cephalopod septa. Paläontologische Zeitschrift, 49:235253.CrossRefGoogle Scholar
Westermann, G. E. G. 1990. New developments in ecology of Jurassic-Cretaceous ammonoids, p. 459478. In Pallini, G., Cecca, F., Cresta, S., and Sanantonio, M. (eds.), Atti del secondo convegno internazionale, Fossili, Evoluzione, Ambiente, Pergola 1987. Tecnostampa, Otra Vetere, Italy.Google Scholar
Westermann, G. E. G. 1993. Hydrostatics and hydrodynamics of cephalopod shells: form, structure, and function. Anales Academia Nacional de Ciencias Exactas, Fisicas y Naturales de Buenos Aires, 45:183204.Google Scholar
Westermann, G. E. G. 1999a. Life habits of Nautiloids, p. 263298. In Savazzi, E. (ed.), Functional Morphology of the Invertebrate Skeleton. John Wiley & Sons, Chichester.Google Scholar
Westermann, G. E. G. 1999b. Recent hypotheses on mechanical and metabolic functions of septal fluting and sutural complexity in post-Carboniferous ammonoids. 5th International Symposium, Cephalopoda—Present and Past. Vienna. Abstract volume:120.Google Scholar
Westermann, G. E. G., and Tsujita, C. J. 1999. Life habits of ammonoids, p. 299325. In Savazzi, E. (ed.), Functional Morphology of the Invertebrate Skeleton. John Wiley & Sons, Chichester.Google Scholar