A novel moderately halophilic bacterium, strain G-19.1(T), has been isolated from a phenol enrichment of samples collected in hypersaline habitats of southern Spain. This enrichment culture was a part of a screening programme to isolate halophilic bacteria able to degrade various aromatic compounds. Strain G-19.1(T) has been characterized as a potential phenol-degrader over a wide range of saline conditions. Strain G-19.1(T) was found to be an aerobic, Gram-positive, endospore-forming, non-pigmented, moderately halophilic rod that grew optimally in media containing 7.5-10% NaCl at pH 7.0. The DNA G+C content was 42.4 mol%. Phylogenetic analysis based on comparison of 16S rRNA gene sequences indicated that the closest relatives were Halobacillus species (96.2-97.0%), although this novel isolate constitutes a separate line of descent within the radiation of Gram-positive rods. The cell-wall peptidoglycan contained meso-diaminopimelic acid, indicating that this strain does not share the main characteristic that differentiates members of the genus Halobacillus (which contain Orn-D-Asp) from other related genera. The predominant cellular fatty acids were anteiso-C(15:0), iso-C(16:0) and iso-C(15:0). On the basis of phenotypic, genotypic and phylogenetic analyses, this isolate should be classified in a novel genus and species, for which the name Thalassobacillus devorans gen. nov., sp. nov. is proposed. The type strain is strain G-19.1(T) (=DSM 16966(T)=CECT 7046(T)=CCM 7282(T)).