A Gram-negative, rod-shaped, Flavobacterium-like bacterial strain, DS-20(T), was isolated from soil from the island of Dokdo, Korea, and subjected to a polyphasic taxonomic study. Strain DS-20(T) grew optimally at pH 6.5-7.0 and 25 degrees C. It contained MK-6 as the predominant menaquinone and iso-C(15 : 0), iso-C(17 : 0) 3-OH and iso-C(17 : 1)omega9c as the major fatty acids. The DNA G+C content was 38.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain DS-20(T) belonged to the genus Flavobacterium. Levels of 16S rRNA gene sequence similarity between strain DS-20(T) and the type strains of recognized Flavobacterium species were below 94.9 %. Strain DS-20(T) differed from phylogenetically related Flavobacterium species in several phenotypic characteristics. On the basis of its phenotypic and phylogenetic distinctiveness, strain DS-20(T) was classified in the genus Flavobacterium as representing a novel species, for which the name Flavobacterium terrigena sp. nov. is proposed. The type strain is DS-20(T) (=KCTC 12761(T)=DSM 17934(T)).

Two Gram-staining-negative, strictly aerobic, non-endospore-forming, non-motile, rod-shaped bacteria, designated strains YIT 12745T and YIT 12746T, were isolated from sludge from a wastewater treatment plant. 16S rRNA gene sequence analyses indicated that these strains belonged to the genus Flavobacterium. In these analyses, strains YIT 12745T and YIT 12746T were most closely related to the type strains of Flavobacterium caeni and Flavobacterium terrigena, with 16S rRNA gene sequence similarity values of 94.9% and 96.2%, respectively. For both novel strains, menaquinone (MK-6) was the only respiratory quinone. The major fatty acids of strain YIT 12745T were iso-C15:1 G (14.4%), iso-C16:0 (13.2%), C15:0 (12.9%), iso-C15:0 (12.9%) and iso-C17:0 3-OH (11.5%). Those of strain YIT 12746T were iso-C15:0 (21.5%), iso-C16:0 (13.3%), C15:0 (12.0%) and iso-C15:1 G (11.9%). The genomic DNA G+C contents of strains YIT 12745T and YIT 12746T were 48.7 and 30.9 mol%, respectively. From their differential phenotypic and phylogenetic characteristics, these strains are considered to represent two novel species of the genus Flavobacterium, for which the names Flavobacterium longum sp. nov. (type strain YIT 12745T=JCM 19141T=DSM 27077T) and Flavobacterium urocaniciphilum sp. nov. (type strain YIT 12746T=JCM 19142T=DSM 27078T) are proposed. Emended descriptions of Flavobacterium caeni and Flavobacterium terrigena are also proposed.

The bacterial phylum Bacteroidetes, characterized by a distinct gliding motility, occurs in a broad variety of ecosystems, habitats, life styles, and physiologies. Accordingly, taxonomic classification of the phylum, based on a limited number of features, proved difficult and controversial in the past, for example, when decisions were based on unresolved phylogenetic trees of the 16S rRNA gene sequence. Here we use a large collection of type-strain genomes from Bacteroidetes and closely related phyla for assessing their taxonomy based on the principles of phylogenetic classification and trees inferred from genome-scale data. No significant conflict between 16S rRNA gene and whole-genome phylogenetic analysis is found, whereas many but not all of the involved taxa are supported as monophyletic groups, particularly in the genome-scale trees. Phenotypic and phylogenomic features support the separation of Balneolaceae as new phylum Balneolaeota from Rhodothermaeota and of Saprospiraceae as new class Saprospiria from Chitinophagia. Epilithonimonas is nested within the older genus Chryseobacterium and without significant phenotypic differences; thus merging the two genera is proposed. Similarly, Vitellibacter is proposed to be included in Aequorivita. Flexibacter is confirmed as being heterogeneous and dissected, yielding six distinct genera. Hallella seregens is a later heterotypic synonym of Prevotella dentalis. Compared to values directly calculated from genome sequences, the G+C content mentioned in many species descriptions is too imprecise; moreover, corrected G+C content values have a significantly better fit to the phylogeny. Corresponding emendations of species descriptions are provided where necessary. Whereas most observed conflict with the current classification of Bacteroidetes is already visible in 16S rRNA gene trees, as expected whole-genome phylogenies are much better resolved.