This taxonomic note addresses a nomenclatural conflict in bacterial classification. Zhou et al. (2008) described a new bacterial species named Bacillus pallidus based on strain CW 7T, but this name is illegitimate because it is a later homonym of Bacillus pallidus Scholz et al. (1988), which remains validly published despite being transferred to the genus Geobacillus. To resolve this conflict, the authors conducted a polyphasic taxonomic reassessment of strain CW 7T, including analysis of 16S rRNA gene sequences, polar lipid profiles, cellular fatty acids, and other chemotaxonomic properties. The polar lipid profile of strain CW 7T differed significantly from that of Bacillus subtilis (the genus type species), supporting placement in a new genus rather than Bacillus. Consequently, the authors propose a new genus, Falsibacillus gen. nov., and designate the organism as Falsibacillus pallidus comb. nov. The type strain CW 7T is characterized as Gram-positive, rod-shaped, spore-forming, and aerobic, with 42.3 mol% G+C content. This nomenclatural change resolves the homonymy while reflecting the organism's distinct chemotaxonomic characteristics.

Key findings

• Bacillus pallidus Zhou et al. 2008 is an illegitimate later homonym of the validly published Bacillus pallidus Scholz et al. 1988, requiring a new name for strain CW 7T.
• Polyphasic analysis, particularly polar lipid profiling, revealed that strain CW 7T differs significantly from Bacillus subtilis and other Bacillus species, warranting placement in a new genus.
• A new genus Falsibacillus gen. nov. is proposed, with Falsibacillus pallidus comb. nov. as the replacement name for the illegitimate Bacillus pallidus Zhou et al. 2008.
• Strain CW 7T is a Gram-positive, spore-forming aerobe with distinctive chemotaxonomic features including specific fatty acid and polar lipid profiles, and 42.3 mol% genomic G+C content.