Flavivirga jejuensis gen. nov., sp. nov., and Flavivirga amylovorans sp. nov., new members of the family Flavobacteriaceae isolated from seawater, and emended descriptions of the genera Psychroserpens and Lacinutrix.

Two yellow, rod-shaped, gram-reaction-negative, strictly aerobic bacterial strains, designated JC2682(T) and JC2681(T), were isolated from a seawater sample of Jeju Island, Korea. The isolates required sea salts for growth and showed gliding motility. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strains JC2682(T) and JC2681(T) shared 96.9 % similarity and formed a robust monophyletic group within the radiation encompassing the family Flavobacteriaceae. This distinct clade, which had varying branch positions depending on the tree-making algorithm used, represents a new genus within the family Flavobacteriaceae. The predominant isoprenoid quinone (menaquinone 6, MK-6) and DNA G+C content (27-33 mol%) were consistent with its assignment to the family Flavobacteriaceae, but the polar lipid profile, fatty acid composition and overall phenotypic traits demonstrated that the test strains were not closely affiliated to any recognized genera. Based on data from the present polyphasic taxonomic study, strains JC2682(T) and JC2681(T) are considered to represent two novel species of a new genus in the family Flavobacteriaceae, for which the names Flavivirga jejuensis gen. nov., sp. nov. and Flavivirga amylovorans sp. nov. are proposed, respectively. The type strain of Flavivirga jejuensis is JC2682(T) ( = KACC 14158(T)  = JCM 17113(T)). The type strain of Flavivirga amylovorans is JC2681(T) ( = KACC 14157(T)  = JCM 17112(T)). Amended descriptions of the genera Psychroserpens and Lacinutrix are provided.