Five alginolytic, facultatively anaerobic, non-motile bacteria were isolated from the gut of abalones Haliotis laevigata and Haliotis rubra. Phylogenetic analyses based on 16S rDNA data indicated that these strains are related closely to Vibrio halioticoli (98 % 16S rDNA sequence similarity). DNA-DNA hybridization and fluorescent amplified fragment length polymorphism fingerprinting demonstrated that the five strains constituted a single species that was different from all currently known vibrios. The name Vibrio superstes sp. nov. (type strain, LMG 21323(T)=IAM 15009(T)=G3-29(T); DNA G+C content, 48.0-48.9 mol%) is proposed to encompass this novel taxon. Several phenotypic features were disclosed that discriminate V. superstes from other Vibrio species: V. superstes sp. nov. and V. halioticoli can be differentiated on the basis of 17 traits (indole production, beta-galactosidase test and assimilation of 15 carbon compounds).