rhodothalassium rhodothalassium in taxonomy, rhodothalassium is a genus of the rhodobacteraceae. up to now there is only one species of this genus known (rhodothalassium salexigens). rhodothalassium scientific classification domain: bacteria phylum: pseudomonadota class: alphaproteobacteria subclass: caulobacteridae order: rhodothalassialesvenkata ramana et al. 2014 family: rhodothalassiaceaevenkata ramana et al. 2014 genus: rhodothalassiumimhoff et al. 1998 species rhodothalassium salexigens (drews 1982) imhoff et al. 1998