gen. nov., sp. nov., a member of the family , isolated from the hindgut of the marine herbivorous fish .

A Gram-stain-negative, non-spore-forming, rod-shaped, obligately anaerobic bacterium, designated strain BP5G, was isolated from the hindgut of a silver drummer () fish collected from the Hauraki Gulf, New Zealand. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that the isolate belonged to the family in the phylum and was most closely related to with 94.06 % sequence identity. Isolate BP5G grew on agar medium containing mannitol and fish gut fluid as carbon sources. Clear colonies of approximately 1 mm diameter of the isolate grew within a week at 20-28 °C (optimum, 28 °C) and pH 7.6-8.5 (optimum, pH 8.5). Strain BP5G was very sensitive to NaCl and the optimal concentration for growth was 0.045 % (w/v). Acetate and propionate were the major fermentation products. The major cellular fatty acids were C, C, C and C. The genome sequence of the isolate was determined. Its G+C content was 38.41 mol% and the 71.41 % average nucleotide identity of the BP5G genome to its closest neighbour with a sequenced genome ( DSM 1682) indicated low genomic relatedness. Based on the phenotypic and taxonomic characteristics observed in this study, a novel genus and species named gen. nov., sp. nov. is proposed for isolate BP5G (=ICMP 24687=JCM 35769).