This article is a validation list (List No. 40) published in the International Journal of Systematic Bacteriology that formally recognizes new bacterial and archaeal names and combinations previously published elsewhere. The journal serves as the official forum for valid publication of taxonomic names in bacteriology. The list includes 16 new names and combinations, such as new species like Aeromonas jandaei, Aeromonas trota, and Enterococcus sulfureus, and new genera including Magnetospirillum and Rhodoferax. Each entry includes the proposed name, organism classification, authors, and nomenclatural type with culture collection references. The article emphasizes that valid publication dates are the date of the validation list, not the original publication date. It also clarifies that validation merely makes names available in nomenclature but does not constitute taxonomic acceptance; organisms may later be reclassified or names shown to be synonyms. Additionally, the article includes a notification section listing names that appeared in previous IJSB issues.

Key findings

• List No. 40 validates 16 new bacterial and archaeal names and combinations through formal publication in IJSB, including three new genera (Acetonema, Magnetospirillum, and Rhodoferax) and multiple new species from clinical and environmental sources.
• Valid publication dates for these names are January 1992 (the validation list date), not the dates of their original publication in other journals.
• Validation of a name in IJSB makes it available for use in bacteriological nomenclature but does not constitute taxonomic acceptance, as organisms may later be reclassified or names may become synonyms.
• The list includes organisms with diverse metabolic capabilities, including H₂/CO₂ acetogens from termite guts, magnetotactic spirilla, phototrophic purple nonsulfur bacteria, and thermophilic archaea.