The New Higher Level Classification of Eukaryotes with Emphasis on the Taxonomy of Protists


Corresponding Author: Denis H. Lynn, Department of Integrative Biology, University of Guelph, Guelph, ON N1G 2W1, Canada—Telephone number: (519) 826 5724; Fax number: (519) 826 5725; e-mail:


Abstract. This revision of the classification of unicellular eukaryotes updates that of Levine et al. (1980) for the protozoa and expands it to include other protists. Whereas the previous revision was primarily to incorporate the results of ultrastructural studies, this revision incorporates results from both ultrastructural research since 1980 and molecular phylogenetic studies. We propose a scheme that is based on nameless ranked systematics. The vocabulary of the taxonomy is updated, particularly to clarify the naming of groups that have been repositioned. We recognize six clusters of eukaryotes that may represent the basic groupings similar to traditional “kingdoms.” The multicellular lineages emerged from within monophyletic protist lineages: animals and fungi from Opisthokonta, plants from Archaeplastida, and brown algae from Stramenopiles.


We acknowledge the critical evaluations of Andrew Roger (Dalhousie University) for the overall structure of this classification. This is a Geological Survey of Canada contribution 2004375.