Origin and Expansion of Foliated Microstructure in Pteriomorph Bivalves

Esteban-Delgado, F. J. and Harper, E. M. and Checa, A. G. and Rodriguez-Navarro, A. B. (2008) Origin and Expansion of Foliated Microstructure in Pteriomorph Bivalves. Biological Bulletin, 214 (April). pp. 153-165.

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Abstract

The ultrastructure of the calcitic prisms of the prismatic shell layers of pteriomorph bivalves was examined by scanning electronic microscopy and diffraction techniques. Results indicate that the internal structure of the prisms is noticeably different among taxa. In species belonging to the families Pinnidae, Pteriidae, and Isognomonidae (Pterioida), prisms are built up with nanometric calcite crystals. On the other hand, Pectinidae, Propeamussliidae, Anomiidae (order Pectinoida) and the Ostreidae (Ostreoida) have prisms constituted by calcitic laths with micrometric size. These laths are indistinguishable from those constituting the foliated microstructure. In almost all cases, there is mineral continuity from the prisms to the underlying foliated layer, as confirmed by X-ray texture analyses. These findings corroborate a previous assumption that the foliated microstructure derived from calcitic prisms, particularly from those with internal foliated structure. The appearance of the foliated microstructure facilitated drastic mineralogical and microstructural changes in pteriomorph shells—for example, the development of rigid shell margins and the production of largely calcitic shells. Such changes have, no doubt, contributed to the evolutionary success of the groups, which have shown a pronounced diversification over time.

Item Type: Article
Uncontrolled Keywords: 2007 AREP IA55
Subjects: 04 - Palaeobiology
03 - Mineral Sciences
Divisions: 04 - Palaeobiology
Journal or Publication Title: Biological Bulletin
Volume: 214
Page Range: pp. 153-165
Depositing User: Sarah Humbert
Date Deposited: 16 Feb 2009 13:02
Last Modified: 23 Jul 2013 10:06
URI: http://eprints.esc.cam.ac.uk/id/eprint/275

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