A tree of 248 Dictyostelium ePK domains is presented. Pseudogenes, Chromosome 2 duplications, and sequences with very divergent ePK domains were omitted. The N- and C-terminus domains of dual-domain kinases, respectively designated by an “-a” or “-b” extension, were analyzed independently. Group and family names are shown in bold type, subfamily names in plain type, and Dictyostelium-specific families and subfamilies in italic. Selected protein names are shown in red. Branch lengths reflect relative distances between ePK domains. A branching order could not be assigned in the region indicated by the small gray circle because of the diversity of the sequences.