Hostname: page-component-cd9895bd7-7cvxr Total loading time: 0 Render date: 2024-12-29T10:14:11.557Z Has data issue: false hasContentIssue false
  • English
  • Français

Developmental regulation and morphological saltation in the heteromorph ammonite Nipponites

Published online by Cambridge University Press:  08 February 2016

Takashi Okamoto
Takashi Okamoto*
Affiliation:
Geological Institute, University of Tokyo, Hongo 7-3-1, Bunkyo-ku Tokyo 113, Japan
Get access Rights & Permissions [Opens in a new window]

Abstract

Nipponites, a Late Cretaceous nostoceratid ammonite, shows a peculiar meandering shell growth in the middle-late stage. Assuming neutral buoyancy, and a constant aperture angle relative to the sea bottom, meandering growth of this ammonite was modeled by computer simulation. In this model, the meandering shell growth is controlled by regulation of life orientation. The remarkable similarity in the coiling modes and rib obliquity patterns between the computer-simulated and actual specimens strongly suggests a free living mode of life in Nipponites with an approximately neutral buoyancy. The simulation also suggests that morphological saltation from a simple helicoid form like Eubostrychoceras japonicum to a meandering shell form like Nipponites occurred abruptly without any intermediate form by minor change of the upper and lower limits of growth direction.

Type
Articles
Information
Paleobiology , Volume 14 , Issue 3 , Summer 1988 , pp. 272 - 286
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

Literature Cited

Diener, C. 1912. Lebensweise und Verbreitung der Ammoniten. Neues Jahrbuch für Mineralogie und Geologie 2:67–89.Google Scholar
Klinger, H. C. 1981. Speculations on buoyancy control and ecology in some heteromorph ammonites. Pp. 337–355. In House, M. R. and Senior, J. R. (eds.), The Ammonoidea. Systematic Association Special Volume 18. Academic Press; London and New York.Google Scholar
Matsumoto, T. 1977. Some heteromorph ammonites from the Cretaceous of Hokkaido. Memoirs of the Faculty of Science, Kyushu University. Series D: Geology 23:303–366.Google Scholar
Matsumoto, T. and Muramoto, T. 1967. Two interesting heteromorph ammonoids from Hokkaido. Memoirs of the Faculty of Science, Kyushu University. Series D: Geology 18:361–366.Google Scholar
Moore, R. C., Lalicker, O., and Fischer, A. 1952. Invertebrate Fossils. McGraw-Hill Co.; New York. 766 pp.Google Scholar
Okamoto, T. 1984. Theoretical morphology of Nipponites (a heteromorph ammonoid). Kaseki (Fossils). Palaeontological Society of Japan 36:37–51. (In Japanese)Google Scholar
Okamoto, T. 1988a. Analysis of heteromorph ammonoids by differential geometry. Palaeontology 31:35–52.Google Scholar
Okamoto, T. 1988b. Changes in life orientation during the ontogeny of some heteromorph ammonoids. Palaeontology 31:281–294.Google Scholar
Tanabe, K., Obata, I., and Futakami, M. 1981. Early shell morphology in some Upper Cretaceous heteromorph ammonites. Transactions and Proceedings of the Palaeontological Society of Japan. New Series 124:215–234.Google Scholar
Tasch, P. 1973. Paleobiology of the Invertebrates. J. Wiley and Sons; New York. 946 pp.Google Scholar
Trueman, A. 1941. The ammonite body chamber, with special reference to the buoyancy and mode of life of the living ammonite. Quarterly Journal of the Geological Society of London 96:339–383.CrossRefGoogle Scholar
Ward, P. D. 1979. Functional morphology of Cretaceous helically-coiled ammonite shells. Paleobiology 5:415–422.CrossRefGoogle Scholar
Ward, P. D. and Westermann, G. E. G. 1977. First occurrence, systematics, and functional morphology of Nipponites (Cretaceous Lytoceratina) from the Americas. Journal of Paleontology 51:367–372.Google Scholar
Yabe, H. 1904. Cretaceous Cephalopoda from the Hokkaido Part II. Journal of the College of Science, Imperial University of Tokyo 20:1–45.Google Scholar