Naming novel prokaryotic taxa discovered in the human gut

In their recent paper on ‘Antibiotics-induced monodominance of a novel gut bacterial order’,1 Hildebrand et al  described metagenomic studies of the human gut following antibiotics intake. They proposed six new prokaryotic taxa: the families Erisaceae, Discordiaceae and Comantemaea, the order Comantemales, the genus Borkfalki and the species B. ceftriaxensis . Except for the first two families, these names refer to yet-uncultivated taxa. For the other names, the authors added superscript ‘U’ for ‘uncultivated’, rather than naming Candidatus taxa as customary.2 Nomenclature of bacteria and archaea is regulated by the rules of the International Code of Nomenclature of Prokaryotes (ICNP).3 Its Appendix 11 provides information about the provisional status Candidatus. Regrettably, all names proposed by Hildebrand et al are problematic as they …