title: Siliceous tablets in the larval shells of apatitic discinid brachiopods
abstract: The marine bivalved Brachiopoda are abundant throughout the geological record and have apatitic (CaPO4-rich) or calcitic (CaCO3-rich) shells. Vesicles covering the larval valves of living apatitic-shelled discinids contain tablets of silica. The tablets are cemented into close-packed mosaics by spherular apatite in glycosaminoglycans. They are usually lost as vesicles degrade but leave imprints on the underlying apatitic shell. Similar imprints ornament larval surfaces of some of the earliest Paleozoic apatitic-shelled brachiopods and may also be indicators of siliceous biomineralization.
authors.affiliation: A. Williams and J. O. Buckman, Palaeobiology Unit, University of Glasgow, Glasgow G12 8QQ, UK. M. Cusack, Department of Geology and Applied Geology, University of Glasgow, Glasgow G12 8QQ, UK. T. Stachel, Institute of Mineralogy, Johann Wolfg.
authors.initials: A
authors.lastname: Williams
authors.initials: M
authors.lastname: Cusack
authors.initials: JO
authors.lastname: Buckman
authors.initials: T
authors.lastname: Stachel