A note on the genus name Rhodococcus Zopf 1891 and its homonyms

The genus name Rhodococcus Zopf 1891 was created to accommodate two species of red pigment (lipochrome)-producing bacteria. However, the genus name Rhodococcus Hansgirg 1884 had already been applied to an algal taxon. The wording of the 1975 and subsequent revisions of the Code dealing with bacteria/prokaryotes is such that the name Rhodococcus Zopf 1891 is illegitimate, despite the fact that it was included on the Approved Lists of Bacterial Names. Further research using databases of scientific names of organisms indicate the status of the name Rhodococcus Zopf 1891 needs to be carefully considered.