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Function and shape in late Paleozoic (mid-Carboniferous) ammonoids

Published online by Cambridge University Press:  08 April 2016

Andrew R. H. Swan
Affiliation:
Department of Geology, University College of Swansea
W. Bruce Saunders
Affiliation:
Department of Geology, Bryn Mawr College, Bryn Mawr, Pennsylvania 19010

Abstract

Analysis of an exhaustive data base of Namurian ammonoid shell characters indicates that the morphology of the Goniatitida can be explained in terms of functional constraints, resulting particularly from hydrostatic and hydrodynamic properties. Modes of life ranging from benthic to pelagic are inferred on this basis for various goniatitid morphotypes; all morphologic features and facies associations are normally compatible with these inferences. Neutral buoyancy is shown to have been likely for all goniatitids. By contrast, the prolecanitids (Order Agoniatitida) exhibit a number of hydrostatic and morphologic anomalies; these anomalies are not explicable using the same principles and remain problematic. This is noteworthy, in that prolecanitids survived the Permian/Triassic extinctions and gave rise to the diverse ceratitic radiation in the Triassic.

The applicability of these results to ammonoids outside the Namurian is assessed, and, in particular, morphologic parallels with Mesozoic ammonites are discussed.

Type
Articles
Copyright
Copyright © The Paleontological Society 

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References

Literature Cited

Bayer, U. and McGhee, G. R. Jr. 1984. Iterative evolution of Middle Jurassic ammonite faunas. Lethaia. 17:116.CrossRefGoogle Scholar
Buckman, S. S. 1892. Monograph of the ammonites of the Inferior Oolite Series. Palaeontogr. Soc. (London).Google Scholar
Chamberlain, J. A. Jr. 1976. Flow patterns and drag coefficients of cephalopod shells. Palaeontology. 19:539563.Google Scholar
Chamberlain, J. A. Jr. 1978. Cephalopod locomotive adaptations: hydrodynamic effect of body extension and shell sculpture. Geol. Soc. Am. Abstr. with Progrm. 10:378.Google Scholar
Chamberlain, J. A. Jr. 1981. Hydromechanical design of fossil cephalopods. Pp. 289336. In: House, M. R. and Senior, J. R., eds. The Ammonoidea. Syst. Assoc. Spec. Vol. 18. Academic Press; London.Google Scholar
Cowen, R., Gertman, R. and Wiggett, G. 1973. Camouflage patterns in Nautilus, and their implications for cephalopod paleobiology. Lethaia. 6:201213.CrossRefGoogle Scholar
Denton, E. J. and Gilpin-Brown, J. B. 1966. On the buoyancy of the pearly Nautilus. J. Mar. Biol. Assoc. U.K. 46:723759.Google Scholar
Ebel, K. 1983. Berechnungen zur Schwebefahigkeit von Ammoniten. N. Jb. Geol. Paläont. Mh. 10:614640.Google Scholar
Ebel, K. 1985. Gehausespirale und Septenform bei Ammoniten unter der Annahme vagil benthischer Lebensweise. Paläont. Z. 59:109123.Google Scholar
Hewitt, R. A. 1985. Numerical aspects of sutural ontogeny in the Ammonitina and Lytoceratina. N. Jb. Geol. Paläont. Abh. 170:273290.CrossRefGoogle Scholar
Kennedy, W. J. and Cobban, W. A. 1976. Aspects of ammonite biology, biogeography and biostratigraphy. Spec. Pap. Palaeont. 17:194.Google Scholar
Kummel, B. and Lloyd, R. M. 1955. Experiments on relative streamlining of coiled cephalopod shells. J. Paleont. 29:159170.Google Scholar
Raup, D. M. 1966. Geometric analysis of shell coiling: general problems. J. Paleont. 40:11781190.Google Scholar
Raup, D. M. 1967. Geometric analysis of shell coiling: coiling in ammonoids. J. Paleont. 41:4365.Google Scholar
Raup, D. M. and Chamberlain, J. A. Jr. 1967. Equations for volume and centre of gravity in ammonoid shells. J. Paleont. 41:566574.Google Scholar
Ruzhencev, V. E. and Bogoslovskaya, M. F. 1978. Namyurski etap y evolutsii ammonoidei. Pozdnenamyurskiye ammonoidei. Trudy Akad. Nauk. S.S.S.R. Paleontol. Inst. 167:1336.Google Scholar
Saunders, W. B. 1973. Upper Mississippian ammonoids from Arkansas and Oklahoma. Geol. Soc. Am. Spec. Pap. 145:1110.Google Scholar
Saunders, W. B. and Shapiro, E. A. 1986. Calculation and simulation of ammonoid hydrostatics. Paleobiology. 12:6479.CrossRefGoogle Scholar
Saunders, W. B. and Swan, A. R. H. 1984. Morphology and morphologic diversity of mid-Carboniferous (Namurian) ammonoids in time and space. Paleobiology. 10:195228.Google Scholar
Schmidt, H. 1930. Uber die Bewegungsweise de Schalencepha-lopoden. Paläont. Z. 12:194208.Google Scholar
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. 96:339383.CrossRefGoogle Scholar
Ward, P. D. 1981. Shell sculpture as a defensive adaptation in ammonoids. Paleobiology. 7:96100.CrossRefGoogle Scholar
Ward, P. D., Greenwald, L., and Magnier, Y. 1981. The chamber formation cycle in Nautilus macromphalus. Paleobiology. 7:481493.CrossRefGoogle Scholar
Westermann, G. E. G. 1966. Covariation and taxonomy of the Jurassic ammonite Sonninia adicra (Wangen). Neues Jahrb. Geol. Paläont. Abh. 124:289312.Google Scholar