Five new species of the coccolithophorid genus Alisphaera (Haptophyta), with notes on their distribution, coccolith structure and taxonomy

Abstract

Five new species of the coccolithophorid genus Alisphaera (Haptophyta/Prymnesiophyta) are described from tropical to arctic waters: Alisphaera extenta Kleijne et al. sp. nov., Alisphaera pinnigera Kleijne et al. sp. nov., Alisphaera quadrilatera Kleijne et al. sp. nov., Alisphaera gauclii Kleijne et al. sp. nov., and Alisphaera uncinata Kleijne et al. sp. nov. (in each case, the taxon authors are the same and in the same order as for the paper itself). Three of these species are dimorphic, and so the description of the previously monomorphic genus Alisphaera is emended; so also is the description of Alisphaera unicornis. All the species currently in Alisphaera (comprising Alisphaera capulata, Alisphaera spatula, Alisphaera ordinata, and A. unicornis, in addition to the five new species) are illustrated, their coccolith distal flange and central area structures are compared, and their geographical distribution is discussed. The proximal flange and the central area of Alisphaera are equivalent to the outer and inner tube cycles of Canistrolithus. The absence of central area cycles with a different crystal nucleation in most Alisphaera spp. and in Canistrolithus implies that these genera should be separated from the family Syracosphaeraceae.