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We highlight the increase in the number of diatom genera being described, and suggest that their description be based on the concept of monophyly. That is, a new genus will contain the ancestor and all its descendants. Past criteria or guidance on how to circumscribe genera are reviewed and discussed, with conceptual and actual exemplars presented. While there is an increase in the rate of genus descriptions in diatoms, and there are many journal and series dedicated to facilitating this important activity, we call for revisionary works on diatom groups, to assess and establish monophyletic groups at all levels of hierarchy in the diatom system.


Bacillariophyta cladistics genera monophyly phylogeny revisionary studies systematics

Article Details

Author Biography

John Patrick Kociolek, University of Colorado

Director and Professor

Museum of Natural History and Department of Ecology and Evolutionary Biology

How to Cite
Kociolek, J. P., & Williams, D. M. (2015). How to define a diatom genus? Notes on the creation and recognition of taxa, and a call for revisionary studies of diatoms. Acta Botanica Croatica, 74(2). Retrieved from