Phylogenomic evidence supporting the reclassification of Cedecea sulfonylureivorans within the genus Dryocola with subdivision into Dryocola clanedunensis subsp. clanedunensis comb. nov. and Dryocola clanedunensis subsp. sulfonylureivorans comb. nov.

The bacterial order <i>Enterobacterales</i> has recently undergone major taxonomic revisions, with several new families and genera described. Within this framework, the rare genus <i>Cedecea</i> and the newly proposed genus <i>Dryocola</i> occupy closely related positions. The present study provides a comprehensive phylogenomic, phenotypic and functional assessment of <i>Cedecea sulfonylureivorans</i> LAM2020^T and <i>Dryocola clanedunensis</i> H11S18^T to clarify their taxonomic relationship. Genomic relatedness indices revealed high similarity between the two type strains, with average nucleotide identity, average amino acid identity and digital DNA-DNA hybridization values exceeding established species delineation thresholds. Phylogenetic analyses based on 16S rRNA, whole genomes and core gene sets consistently placed the two strains in a robustly supported monophyletic clade. These findings were further supported by shared metabolic and phenotypic traits. Taken together, the evidence demonstrates that <i>C. sulfonylureivorans</i> and <i>D. clanedunensis</i> represent members of the same biological species. Accordingly, and in line with Rule 42 of the International Code of Nomenclature of Prokaryotes, we propose the reclassification of <i>C. sulfonylureivorans</i> Li <i>et al.</i> 2024 as a later heterotypic synonym of <i>D. clanedunensis</i> Maddock <i>et al.</i> 2023. Furthermore, we propose two subspecies within this species: <i>D. clanedunensis</i> subsp. <i>clanedunensis</i> comb. nov. and <i>D. clanedunensis</i> subsp. <i>sulfonylureivorans</i> comb. nov.