Taxonomic characterization of Thaumasiovibrio clandestinus sp. nov., isolated from marine mud in Gochang and emended description of the genus Thaumasiovibrio

A phylogenetically distinct bacterial strain, designated as DFM-14^T, was isolated in 2022 from marine mud collected in Gochang, Jeollabuk-do, South Korea, and characterized using a polyphasic taxonomic approach. The isolate is Gram-stain-negative, motile, pale white and coccoid-shaped, typically forming clusters. It is facultatively aerobic, and phylogenetic analysis of the 16S rRNA gene placed it within the genus <i>Thaumasiovibrio</i> (family <i>Vibrionaceae</i>, phylum <i>Pseudomonadota</i>). Strain DFM-14^T formed a distinct clade with <i>Thaumasiovibrio subtropicus</i> C4V358^T and <i>Thaumasiovibrio occultus</i> C4II189ᵀ, sharing 16S rRNA gene sequence similarities of 95.6% and 95.2%, respectively. The major fatty acids are C_{12 : 0}, C_{12 : 0} 3-OH, C_{16 : 0}, C_{16 : 1} <i> ω</i>9c and C_{18 : 1} <i> ω</i>9c, while the predominant polar lipids are diphosphatidylglycerol, phosphatidylglycerol and glycolipids. The draft genome is 4.4 Mb in size, assembled into 56 contigs, and contains 4,445 coding sequences and 110 RNAs (8 rRNAs and 102 tRNAs), with a G+C content of 45.4 mol%. Optimal growth occurs at 25 °C, pH 7.0 and 2% (w/v) NaCl. Based on phenotypic, phylogenetic, chemotaxonomic and genomic evidence, strain DFM-14ᵀ represents a novel species of the genus <i>Thaumasiovibrio</i>, for which the name <i>Thaumasiovibrio clandestinus</i> sp. nov. is proposed. The type strain is DFM-14^T (=KEMB 24352^T=JCM 37837^T=KCTC 8887^T).