Maximum likelihood tree of selected representative concatenated 18S and 28S rDNA sequences showing Meringosphaera within the Centroplasthelida. The tree was reconstructed with a GTR model, with 4 gamma categories, and support values correspond to rapid bootstrap with 1,000 replicates. The two groups are designated as group 1 and group 2, these two groups corresponded to clustering the Meringosphaera 18S rDNA sequences by >97% identity (the separate 18S and 28S phylogenies are available in the Figshare repository D2.1). The Meringosphaera sequences written in bold were generated by this project, and all other previous sequences are unidentified environmental sequences. Haptophyte sequences were used as an outgroup.
