gen. nov. sp. nov. and gen. nov. sp. nov., two novel heterotrophs from brittle star .

Two novel Gram-stain-negative, strictly aerobic, halophilic and non-motile bacterial strains, designated NKW23 and NKW57, were isolated from a brittle star collected from a tidal pool in Wakayama, Japan. The results of phylogenetic analysis based on 16S rRNA gene sequences indicated that NKW23 represented a member of the family , with CAU 1123 as its closest relative (94.4% sequence identity). NKW57 was identified as representing a member of the family with up to 94.9% sequence identity with its closest relatives. Both strains displayed average nucleotide identity (ANI) and digital DNA-DNA hybridisation (dDDH) values below the species delimitation threshold against their closest relatives. Additionally, amino acid identity (AAI) values of both strains fell below the genus-defining threshold. Phylogenetic trees based on genome sequences indicated that NKW23 formed a novel lineage, branching deeply prior to the divergence of the genera and with an evolutionary distance (ED) of 0.31-0.32, indicative of genus-level differentiation. NKW57 similarly formed a distinct lineage separate from the species of the genus . The major respiratory quinones of NKW23 and NKW57 were ubiquinone-10 (Q-10) and Q-8, respectively. The genomic DNA G+C contents of NKW23 and NKW57 were 71.4 and 58.8%, respectively. On the basis of the physiological and phylogenetic characteristics, it was proposed that these strains should be classified as novel species representing two novel genera: gen. nov., sp. nov., with strain NKW23 (=JCM 36220=KCTC 8062) as the type strain, and gen. nov., sp. nov., with strain NKW57 (=JCM 36221=KCTC 8063) as the type strain.