sphingomonadales sphingomonadales the sphingomonadales are an order of the alphaproteobacteria. sphingomonadales scientific classification domain: bacteria phylum: pseudomonadota class: alphaproteobacteria order: sphingomonadalesyabuuchi and kosako 2006 families erythrobacteraceae lee et al. 2005 sphingomonadaceae kosako et al. 2000 sphingosinicellaceae hördt et al. 2020 zymomonadaceae hördt et al. 2020 phylogeny the currently accepted taxonomy is based on the list of prokaryotic names with standing in nomenclature and the phylogeny is based on whole-genome sequences. sphingomonadales sphingosinicellaceae zymomonadaceae sphingomonadaceae erythrobacteraceae outgroup rhodospirillales