Proposed minimal standards for description of new taxa in the order Halobacteriales

In accordance with Recommendation 30b of the International Code of Nomenclature of Bacteria, which calls for the development of minimal standards for describing new species, we propose minimal standards for description of new taxa in the order Halobacteriales. The minimal standards include information on the following characteristics: cell morphology; motility; pigmentation; the requirement for salt to prevent cell lysis; optimum NaCl and MgCl₂ concentrations for growth and range of salt concentrations enabling growth; temperature and pH ranges for growth; anaerobic growth in the presence of nitrate or arginine; acid production from a range of carbohydrates; ability to grow on single carbon sources; catalase and oxidase tests; hydrolysis of starch, casein, and Tween 81; sensitivity to different antibiotics; and polar lipids. The placement of a new taxon should be consistent with phylogeny, which is usually based on 16S rRNA nucleotide sequence information, and with DNA-DNA hybridization data in the case of descriptions of new species. This proposal has been endorsed by the members of the Subcommittee on the Taxonomy of Halobacteriaceae of the International Committee on Systematic Bacteriology.