Phylogenetic relationships among the species included in our study, based on results from four recent studies that group the six supergroups into three different megagroups [9–12]. Relationships within Fungi follow Fitzpatrick et al. . The genomes of the nucleomorphs of Guillardia theta and Bigelowiella natans were included in the bioinformatic searches but not in tree because its phylogenetic position does not match the position of the host. The different eukaryotic supergroups are highlighted. The phylogenetic position of Emiliana is still unclear (see [11, 12]), and thus, it was left in black.