Maximum likelihood cladistic phylogenetic tree of ITS fragments from representative OTUs. Branches with >80% bootstrap support are marked with filled circles. Reference ITS sequences include isolates MED4, MIT9515, AS9601, MIT9215, MIT9301, MIT9312, MIT9211, NATL1A, NATL2A and SS120, and are indicated by red branches. Green, yellow and purple branch color as well as the external brackets indicate ecotype assignment. Internal shading indicates the sub-ecotype clades (green: eHL-I.1–4 and yellow: eHL-II.1–4) and eHL-VI (purple). Unshaded clades were included in ecotype analyses but were not examined in sub-ecotype clade analyses. The external heat map is the natural log of the sum across all stations of the rarefied sequence abundance for each OTU.