On validly published names, correct names, and changes in the nomenclature of phyla and genera of prokaryotes: a guide for the perplexed.

The nomenclature of prokaryotes is regulated by the rules of the International Code of Nomenclature of Prokaryotes. In view of inconsistencies in the use of names of many prokaryotic taxa and confusion caused by recent nomenclature changes, this essay presents an overview of how to use correct names of taxa. It includes information on validly published names of prokaryotic phyla, the way to deal with names of species that were transferred to newly created genera, and the nomenclature of uncultivated Candidatus taxa. It also provides recommendations for databases that provide reliable nomenclature information.