Proposed modifications to Rule 40d of the International Code of Nomenclature of Prokaryotes Tindall, B. J.,, 69, 1519-1520 (2019), doi = https://doi.org/10.1099/ijsem.0.003264, publicationName = Microbiology Society, issn = 1466-5026, abstract= The wording of Rule 40d was discussed at the XIIth International (IUMS) Congress of Bacteriology and Applied Microbiology, Istanbul in 2008 and some changes were made to clarify how the authorship of names covered by this rule were to be cited. However, a key topic that was raised and discussed was the issue of wording that either automatically creates a subspecies name or whether an automatic consequence of the rule was that a subspecies name based on the nomenclatural type of the corresponding species was required, but must be validly published in accordance with the Rules of the International Code of Nomenclature of Prokaryotes. The differences are subtle, but important., language=, type=