Proposal to conserve the adjectival form of the specific epithet in the reclassification of Bacteroides forsythus Tanner et al. 1986 to the genus Tannerella Sakamoto et al. 2002 as Tannerella forsythia corrig., gen. nov., comb. nov. Request for an Opinion

This paper proposes a nomenclatural correction for an oral anaerobic bacterium originally described as Bacteroides forsythus. When Sakamoto and colleagues reclassified this organism into the new genus Tannerella, they changed the specific epithet to forsythensis. The authors argue that the original adjectival form forsythia should be retained instead, as a minimal gender-agreement change appropriate for transfer to the feminine genus Tannerella. They contend that forsythensis unnecessarily deviates from the original epithet, violating Rule 41a of the International Code of Nomenclature of Bacteria, which requires epithet retention during genus transfer. Additionally, the authors argue that the -ensis ending is linguistically inappropriate for institutional names and better reserved for geographical locations. They propose that Tannerella forsythia corrig. is the correct combination and request an Opinion from the Judicial Commission to conserve the original adjectival form, supporting stability and clarity in bacterial nomenclature.

Key findings

• The original species epithet forsythus should be retained in corrected adjectival form (forsythia) when Bacteroides forsythus is reclassified to genus Tannerella, requiring only gender agreement change.
• The forsythensis epithet proposed by Sakamoto et al. constitutes an unnecessary and confusing change that violates Rule 41a requiring epithet retention during genus transfer.
• The -ensis linguistic ending is most appropriate for geographical locations (cities, regions, countries) rather than institutions, making simple adjectival forms more suitable for institution-derived species names.
• Conserving the original epithet form (forsythia) aligns with the primary principle of the International Code of Nomenclature of Bacteria emphasizing nomenclatural stability.