Phylogenetic tree highlighting the position of S. mucosus relative to the type strains of the type species of the other genera within the family Rhodobacteraceae. The tree was inferred from 1,331 aligned characters of the 16S rRNA gene sequence under the maximum likelihood (ML) criterion as previously described . Rooting was done initially using the midpoint method  and then checked for its agreement with the current classification (Table 1). The branches are scaled in terms of the expected number of substitutions per site. Numbers adjacent to the branches are support values from 650 ML bootstrap replicates (left) and from 1,000 maximum-parsimony bootstrap replicates (right) if larger than 60% . (That is, the backbone of the tree is largely unresolved.) Lineages with type strain genome sequencing projects registered in GOLD  are labeled with one asterisk, those also listed as ‘Complete and Published’ with two asterisks [3,17].