The Ammonoidea (ammonoids) are an order of the class Cephalopoda (q.v.), phylum Mollusca. The nearest living relative of the ammonoids is the pearly Nautilus of which Oliver Wendell Holmes wrote “This is the ship of pearl, which, poets feign, /Sails the unshadowed main.”
The hollow shell of most ammonoids is essentially a cone, coiled in a plane, regularly partitioned into chambers. The center of the outer margin of the coil is the venter; the corresponding part of the inner margin is the dorsum (Fig. 1). The essential difference between the nautiloid and ammonoid shell is in the partitions that separate the chambers; the nautiloid partitions are undulating and of “free-form” appearance, whereas those of the ammonoid are much more highly crenulated and therefore more complex.
The ammonoid shell.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Arkell, W. J., 1950. A classification of the Jurassic ammonites, J. Paleontology, 24, 354–364.
Arkell, W. J., et al., 1957. Cephalopoda: Ammonoidea, in R. C. Moore, ed., Treatise on Invertebrate Paleontology, pt. L, Lawrence Kansas: Geol. Soc. Amer. and Univ. Kansas Press, 490p.
Bather, F. A., 1894. Cephalopod beginnings, Nature Sci., 5, 421–436.
Donovan, D. T., 1964. Cephalopod phylogeny and classification, Biol. Rev. Cambridge Phil. Soc., 39, 259–287.
Donovan, D. T., 1973. The influence of theoretical ideas on ammonite classification from Hyatt to Trueman, Univ. Kansas Paleontol. Contrib. Paper, 62, 16p.
Erben, H. K., 1964. Die evolution der altesten Ammonoidea (Lieferung 1), Neues Jahrb. Geol. Paläontol., Abh., 120, 107–212.
Gordon, W. A., 1976. Ammonoid provinciality in space and time, J. Paleontology, 50, 521–535.
Holder, H., 1975. Forchungsbericht uben Ammoniten, Paläont. Zeitschr., 49, 443–511.
Kennedy, W. J., 1977. Ammonite evolution, in A. Hallam, ed., Patterns of Evolution. Amsterdam: Elsevier, 251–304.
Kennedy, W. J., and Cobban, W. A., 1976. Aspects of ammonite biology, biogeography and biostratigraphy, Spec. Paper Palaeontology, 17, 94p.
Kullmann, J., and Weidmann, J., 1970. Significance of sutures in the phylogeny of Ammonoidea, Univ. Kansas Paleontol. Contrib. Paper, 47, 32p.
Kummel, B., 1952. A classification of the Triassic ammonoids, J. Paleontology, 26, 847–853.
Kummel, B., 1954. Status of invertebrate paleontology, 1953. V. Mollusca: Cephalopoda, Bull. Mus. Comp. Zool. Harvard Univ., 112, 181–192.
Makowski, H. K., 1962. Problem of sexual dimorphism in ammonites, Paleontologia Polonica, 12, 89p.
Miller, A. K., and Furnish, W. M., 1954. The classification of the Paleozoic ammonoids, J. Paleontology, 28, 685–692.
Nelson, C. M., 1968. Ammonites: Ammon's horns into cephalopods, J. Soc. Bibliography Nat. Hist., 5, 1–18.
Ruzhencev, V. E., 1960. Ammonoid classification problems, J. Paleontology, 34, 609–619.
Schindewolf, O. H., 1968. Homologie and Taxonomie —Morphologische Grundlegung und phylogenetische Auslegung, Acta Biotheoretica, 18, 235–283.
Spath, L. F., 1933. The evolution of the Cephalopoda, Biol. Rev. Cambridge Phil. Soc., 8, 418–462.
Stenzel, H. B., 1964. Living Nautilus, in R. C. Moore, ed., Treatise on Invertebrate Paleontology, pt. K, Mollusca 3 Lawrence, Kansas: Geol. Soc. Amer., and Univ. Kansas Press, K59–K93.
Trueman, A. E., 1941. The ammonite body-chamber, with special reference to the buoyancy and mode of life of the living ammonite, Quart. J. Geol. Soc. London, 96, 339–383.
Westermann, G. E. G., 1971. Form, structure and function of the shell and siphuncle in coiled Mesozoic ammonites, Roy. Ontario Mus. Life Sci. Contrib., 78, 39p.
Wright, C. W., 1952. A classification of Cretaceous ammonites, J. Paleontology, 26, 213–222.
Cross-references
Rights and permissions
Copyright information
© 1979 Dowden, Hutchinson & Ross, Inc.
About this entry
Cite this entry
Young, K. (1979). Ammonoidea . In: Paleontology. Encyclopedia of Earth Science. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-31078-9_5
Download citation
DOI: https://doi.org/10.1007/3-540-31078-9_5
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-0-87933-185-6
Online ISBN: 978-3-540-31078-5
eBook Packages: Springer Book Archive