A reappraisal of the taxonomy and biodiversity of the extant coccolithophore genus Palusphaera (Rhabdosphaeraceae, Prymnesiophyceae)

ABSTRACT

The genus Palusphaera Lecal-Schlauder emend. R.E. Norris is a distinctive modern coccolithophore that accommodates monomorphic, monothecate coccospheres with one type of spine-bearing heterococcoliths. Having examined a set of scanning electron microscopy images from our collections, we were able to demonstrate that four distinct species of Palusphaera exist in the modern oceans, including the type species Palusphaera vandelii, an informally proposed form, Palusphaera sp. 1 (type robusta) that is herein taxonomically ratified as Palusphaera crosiae sp. nov., and a distinctive morphotype, which is formally described as Palusphaera bownii sp. nov. Biometric analyses and observations on the morphologies of numerous P. vandelii specimens revealed the existence of a further form, and its commonly distinguished coccolith morphotypes are therefore taxonomically separated from Palusphaera vandelii and established as a discrete species, Palusphaera probertii sp. nov.

KEYWORDS:

• Coccolithophores
• Living
• Phytoplankton
• Syracosphaerales
• Taxonomy

Acknowledgements

We thank the captains and the crews of R/V Poseidon, R/V James Clark Ross, RRS Discovery, R/V Meteor, R/V L’Atalante, R/V Hesperides and R/V Villa Velebita for their valuable assistance in seawater sampling in the Atlantic and Pacific Oceans and in the Mediterranean and Adriatic Seas. We warmly acknowledge Markus Geisen, Alexandra Broerse, Andy Howard, Claudia Sprengel, Daniel Vaulot and Masanobu Kawachi for their assistance in obtaining seawater samples and/or with the scanning electron microscope analyses. We gratefully acknowledge Jelena Godrijan for providing the sample from the Adriatic Sea used in this study. Special thanks are due to Giles Miller for his assistance in cataloguing our material at the Natural History Museum London, UK. We also extend our gratitude to the editor and the two anonymous reviewers for their insightful suggestions that greatly improved the quality of the article. The work contains data supplied by the Natural Environment Research Council.

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Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

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Funding

This work is a contribution to the EC-TMR research project CODENET, Coccolithophorid Evolutionary Biodiversity and Ecology Network (Contract No. ERB-FRMX-CT97-0113). OAA was supported by the UK Natural Environment Research Council under Grant number NE/S007474/1.