show Abstracthide AbstractSulfur-oxidizing bacteria of the Thioglobaceae family are widespread in diverse marine habitats from hydrothermal vents, to oxygen minimum zones, where they impact global biogeochemical cycles and have adopted a diverse repertoire of host-associated and free-living lifestyles. The evolutionary driving forces that led to the versatility and global success of this family, including the adoption of multiple lifestyles, have been unknown so far. To understand the underlying evolutionary signatures among SUP05 lineages of different lifestyles, we investigated the genomic diversity within the SUP05 clade on a range of phylogenetic levels from genus to strain.