Hostname: page-component-848d4c4894-hfldf Total loading time: 0 Render date: 2024-06-02T13:31:19.363Z Has data issue: false hasContentIssue false

Shell composition, cryptic costae, complex composite molds, and taphonomic chicanery in Mytiloides (Inoceramidae, Bivalvia)

Published online by Cambridge University Press:  20 May 2016

James S. Crampton*
Affiliation:
Institute of Geological and Nuclear Sciences, P. O. Box 30-368, Lower Hutt, New Zealand,

Abstract

Many bivalves and brachiopods possess multilayered shells. In one such bivalve, Mytiloides ipuanus (Wellman, 1959) (Inoceramidae), the mineralized shell comprises an outer prismatic calcite layer and an inner nacreous aragonite layer. Each of the three shell surfaces—the external, internal, and shell layers' interface—has a distinct sculpture. Pronounced costae on the shell interface are “cryptic” in the sense that, in life, they would have been barely expressed on the internal surface and only expressed as comparatively weak, broad, rounded costae on the external surface. In fossil specimens, depending on the timing of shell dissolution relative to compaction and lithification, any of these sculptures may be preserved and combined in various ways on simple or composite surfaces/molds. Many of the resulting specimens appear to be morphologically quite distinct from each other. The form and distribution of particular “taphomorphs,” however, can be predicted from a knowledge of shell mineralogy and taphofacies. The different sculptures present on the three shell surfaces, and their wide range of taphonomic expressions, had not been recognized previously, resulting in the erection of three nominal taxa for this single species, based on different taphomorphs. It is not clear whether similar problems remain undetected in other multi-shell-layered invertebrate fossil groups.

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

Behrensmeyer, A. K., and Kidwell, S. M. 1985. Taphonomy's contributions to paleobiology. Paleobiology, 11:105119.Google Scholar
Brett, C. E., and Baird, G. C. 1986. Comparative taphonomy: A key to paleoenvironmental interpretation based on fossil preservation. Palaios, 1:207227.CrossRefGoogle Scholar
Carter, J. G. 1980. Environmental and biological controls of bivalve shell mineralogy and microstructure, p. 69113. In Rhoads, D. C. and Lutz, R. A. (eds.), Skeletal Growth Of Aquatic Organisms, Topics in Geobiology, 1. Plenum Press, New York.CrossRefGoogle Scholar
Crampton, J. S. 1996a. Inoceramid bivalves from the Late Cretaceous of New Zealand. Institute of Geological and Nuclear Sciences Monograph, 14:1188.Google Scholar
Crampton, J. S. 1996b. Biometric analysis, systematics and evolution of Albian Actinoceramus (Cretaceous Bivalvia, Inoceramidae). Institute of Geological and Nuclear Sciences Monograph, 15:180.Google Scholar
Crampton, J. S. 1998. Ontogenetic variation and inoceramid morphology: a note on early Coniacian Cremnoceramus bicorrugatus (Cretaceous Bivalvia). Acta Geologica Polonica, 48:367376.Google Scholar
Crampton, J. S., Tulloch, A. J., Wilson, G. J., Ramezani, J., and Speden, I. G. 2004. Definition, age and correlation of the Clarence Series stages in New Zealand (late Early to early Late Cretaceous). New Zealand Journal of Geology and Geophysics, 47:119.CrossRefGoogle Scholar
Davies, D. J., Powell, E. N., and Stanton, R. J. 1989. Relative rates of shell dissolution and net sediment accumulation—a commentary: Can shell beds form by the gradual accumulation of biogenic debris on the sea floor? Lethaia, 22:207212.CrossRefGoogle Scholar
Field, B. D., Uruski, C., Beu, A., Browne, G., Crampton, J., Funnell, R., Killops, S., Laird, M., Mazengarb, C., Morgans, H., Rait, G., Smale, D., and Strong, P. 1997. Cretaceous–Cenozoic geology and petroleum systems of the East Coast region, New Zealand. Institute of Geological and Nuclear Sciences Monograph, 13:1244 + enclosures.Google Scholar
Harries, P. J., and Crampton, J. S. 1998. The inoceramids. American Paleontologist, 6:26.Google Scholar
Harries, P. J., Kauffman, E. G., Crampton, J. S., Bengtson, P., Cech, S., Crame, J. A., Dhondt, A. V., Ernst, G., Hilbrecht, H., Lopez, G., Mortimore, R., Tröger, K.-A., Walaszczyk, I., and Wood, C. J. 1996. Lower Turonian Euramerican Inoceramidae: A morphologic, taxonomic, and biostratigraphic overview. A report from the First Workshop on Early Turonian Inoceramids (Oct. 5–8, 1992) in Hamburg, Germany; organized by Heinz Hilbrecht and Peter J. Harries. Mitteilungen aus dem Geologisch-Paläontologischen Institut der Universität Hamburg, 77:641671.Google Scholar
Houša, V. 1994. Variability and classification of inoceramids. Exemple [sic] of Inoceramus bohemicus Leonhard from the Cenomanian of Korycany (Czech Rupublic). Palaeopelagos Special Publication, 1:181202.Google Scholar
Johnston, P. A., and Collom, C. J. 1998. The bivalve heresies—Inoceramidae are Cryptodonta, not Pteriomorpha, p. 347360. In Johnston, P. A. and Haggart, J. W. (eds.), Bivalves: An Eon of Evolution. Paleobiological Studies Honoring Norman D. Newell. University of Calgary Press, Calgary.Google Scholar
Kennedy, W. J., and Hall, A. 1967. The influence of organic matter on the preservation of aragonite in fossils. Proceedings of the Geological Society of London, 1643:253255.Google Scholar
Martin, R. E. 1999. Taphonomy; A Process Approach. Cambridge Paleobiology Series, Cambridge University Press, Cambridge, 508 p.CrossRefGoogle Scholar
McAlester, A. L. 1962. Mode of preservation in Early Paleozoic pelecypods and its morphologic and ecologic significance. Journal of Paleontology, 36:6973.Google Scholar
Palmer, T. J., Hudson, J. D., and Wilson, M. A. 1988. Palaeoecological evidence for early aragonite dissolution in ancient calcite seas. Nature, 335:809810.CrossRefGoogle Scholar
Pokhialainen, V. P. 1985. The structure of inoceram populations, p. 91103. In Pokhialainen, V. P. (ed.), Dvustvorchatye i golovonogie molliuski Mezozoia Severo-Vostoka SSSR [Bivalve and Cephalopod Molluscs of the Mesozoic of the North-Eastern U.S.S.R.]. Dal'nevostochnyi Nauchnyi Tsentr, Severo-Vostochnyi Kompleksnyi Nauchno-Issledovatel'skii Institut, Magadan, Russia. (In Russian)Google Scholar
Pokhialainen, V. P., and Koliasnikov, I. A. 1985. About the nature of an unusual replacement of the lamellar layer of colonicerams by chlorite (Far Eastern Asia). Litologiia i Poleznye Iskopaemye [Moscow], 6:122125. (In Russian)Google Scholar
Tanabe, K. 1973. Evolution and mode of life of Inoceramus (Sphenoceramus) naumanni Yokoyama emend., an Upper Cretaceous bivalve. Transactions and Proceedings of the Palaeontological Society of Japan, n. s., 92:163184.Google Scholar
Voigt, E. 1996. Submarine Aragonit-Lösung am Boden des Schreibkreide-Meeres; palaeontological evidence for aragonite shell dissolution on the chalk sea floor. Mitteilungen aus dem Geologisch-Paläontologischen Institut der Universität Hamburg, 77:577601.Google Scholar
Walaszczyk, I. 1997. Significance of the ligament area in species level taxonomy of inoceramid bivalves; how much variation is lodged in a single species? Freiberger Forschungsheft, C468:289303.Google Scholar
Wellman, H. W. 1959. Divisions of the New Zealand Cretaceous. Transactions of the Royal Society of New Zealand, 87:99163.Google Scholar
Williams, A. 1997. Shell structure, p. H267H320. In Kaesler, R. L. (ed.), Treatise on Invertebrate Paleontology, Part H, Brachiopoda 1 (revised edition). The Geological Society of America and the University of Kansas, Boulder, Colorado.Google Scholar