FIG 4.

Maximum likelihood (ML) tree based on the 18S rRNA gene sequences of 55 ciliates showing the phylogenetic position of the magnetic ciliate Uronema marinum strain Mj1 within the subclass Scuticociliatia. The tree was inferred by estimating a GTRGAMMAI model to describe nucleotide evolution with RAxML 8.2.6 (68) and rooted with Paramecium tetraurelia strain 51. GenBank accession numbers are given next to strain names. The tree was drawn to scale, and branch lengths represent the number of base substitutions per site. A total of 599 bootstrap replicates automatically determined by the MRE-based bootstopping criterion were conducted under the rapid bootstrapping algorithm to test robustness of the nodes, among which 100 were sampled to generate proportional support values. Nodes annotated with gray circles are supported by bootstrap values higher than 70%.