A Gram-stain-negative, aerobic, non-spore-forming, motile by single polar flagellum and ovoid or rod-shaped bacterial strain, designated JBTF-M18, was isolated from tidal-flat sediment collected from the Yellow Sea, Republic of Korea. The neighbour-joining phylogenetic tree of 16S rRNA gene sequences showed that strain JBTF-M18 fell within the clade comprising the type strains of species. Strain JBTF-M18 exhibited 16S rRNA gene sequence similarity values of 97. 1-98.8 % to the type strains of , , and and of less than 96.9 % to the type strains of the other species. The average nucleotide identity and digital DNA-DNA hybridization values between strain JBTF-M18 and the type strains of and were 72.0 and 89.5% and 18.9 and 38.1 %, respectively. DNA-DNA relatedness values between strain JBTF-M18 and the type strains of and were 14 and 19 %, respectively. The DNA G+C content of strain JBTF-M18 from genomic sequence data was 52.9 %. Strain JBTF-M18contained MK-6 as the predominant menaquinone and Q-7 and Q-8 as the predominant ubiquinones. It had iso-C, summed feature 3 (Cω and/or Cω) and C as the major fatty acids. The major polar lipids of strain JBTF-M18 were phosphatidylethanolamine and phosphatidylglycerol. Distinguished phenotypic properties, along with the phylogenetic and genetic distinctiveness, revealed that strain JBTF-M18 is separated from recognized species. On the basis of the data presented, strain JBTF-M18 is considered to represent a novel species of the genus , for which the name sp. nov. is proposed. The type strain is JBTF-M18 (=KACC 19869=NBRC 113583).