Poseidonibacter parvus sp. Nov., isolated from a squid

A Gram-stain-negative, aerobic, short rod-shaped, motile, brownish-coloured bacterium, termed strain LPB0137^T, was isolated from a squid. Its cells could grow weakly on marine agar 2216 with 0.04% 2,3,5-triphenyl tetrazolium chloride (TTC). Each cell of strain LPB0137^T has a circular chromosome with a length of 2.87 Mb and 27.7 mol% DNA G+C content. The genome includes 2698 protein-coding genes and six rRNA operons. In 16S rRNA gene sequence trees, strain LPB0137^T formed a robust mono-phyletic clade with Poseidonibacter antarcticus SM1702^T with a sequence similarity of 98.3%. However, the average nucleotide identity and in silico DNA–DNA hybridization values between the two type strains were low (83.9 and 28.1%, respectively). The overall phenotypic and genomic features of strain LPB0137^T supported its assignment to the genus Poseidonibacter. However, the relatively low gene and genome sequence similarity between this strain and other type strains of the genus Poseidonibacter and several enzymatic characteristics indicated the taxonomic novelty of the isolated strain as a new member of the genus Poseidonibacter. Therefore, based on the phylogenetic and phenotypic characteristics of LPB0137^T, we proposed a novel species of the genus Poseidonibacter for it, with the name Poseidonibacter parvus sp. nov. The type strain of this new species is thus LPB0137^T (=KACC 18888^T=JCM 31548^T).