Maximum-likelihood (ML) tree of internal transcribed spacer 2 (ITS2) sequences of Symbiodinium from zoanthid specimens from Taiwan. Novel sequences from this study with specimen numbers (see Table 1), host species names, and sampling regions are in boldface. Subclades C1 and C3 (common Pacific types) are designated by thick vertical lines. Sequences from previous studies are included with GenBank accession numbers and/or subclade names (sensu LaJeunesse 2001). Potential new novel subclades are designated by dashed boxes. Values at nodes respectively represent ML and neighbor-joining (NJ) bootstrap values.