title: COCCOLITH FUNCTION AND MORPHOGENESIS: INSIGHTS FROM APPENDAGE-BEARING COCCOLITHOPHORES OF THE FAMILY SYRACOSPHAERACEAE (HAPTOPHYTA)(1).
abstract: The morphology of three remarkable genera of coccolithophores, Ophiaster, Michaelsarsia, and Calciopappus, is reviewed based on new images using field emission scanning electron microscopy. Each of these genera characteristically forms coccospheres with long appendages formed of highly modified coccoliths, which radiate from either the circum-flagellar pole of the coccosphere (Calciopappus and Michaelsarsia) or the antapical pole (Ophiaster). For each genus, it is shown that the appendage coccoliths can also occur in an alternative orientation appressed to the main coccosphere. It is hypothesized that the appendage coccoliths are initially deployed in the appressed orientation and that extension of the appendages is a dynamic response to environmental stress. The observations suggest that coccoliths are more sophisticatedly adapted to specific functions than has been assumed and that the cytoskeleton plays more active roles in coccolith morphogenesis and deployment than has previously been inferred.
authors.affiliation: Palaeontology Department, The Natural History Museum, London SW7 5BD, UKBundesanstalt für Geowissenschaften und Rohstoffe (Federal Institute for Geosciences and Natural Resources), Postfach 510153, 30631 Hannover, GermanyStation Biologique de Roscoff, 29682 Roscoff, France.
authors.forename: Jeremy R
authors.initials: JR
authors.lastname: Young
authors.affiliation: Palaeontology Department, The Natural History Museum, London SW7 5BD, UKBundesanstalt für Geowissenschaften und Rohstoffe (Federal Institute for Geosciences and Natural Resources), Postfach 510153, 30631 Hannover, GermanyStation Biologique de Roscoff, 29682 Roscoff, France.
authors.forename: Harald
authors.initials: H
authors.lastname: Andruleit
authors.affiliation: Palaeontology Department, The Natural History Museum, London SW7 5BD, UKBundesanstalt für Geowissenschaften und Rohstoffe (Federal Institute for Geosciences and Natural Resources), Postfach 510153, 30631 Hannover, GermanyStation Biologique de Roscoff, 29682 Roscoff, France.
authors.forename: Ian
authors.initials: I
authors.lastname: Probert
keywords: biomineralization; coccolithophore; cytoskeleton; functional morphology; haptophyte