An aquatic bacterium, strain GPTSA100-15T, was isolated on nutritionally poor medium TSBA100 (tryptic soy broth diluted 100 times and solidified with 1.5 % agarose) and characterized using a polyphasic approach. The isolate was unable to grow on commonly used nutritionally rich media such as tryptic soy agar, nutrient agar and Luria-Bertani agar. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the isolate was affiliated with the family 'Flexibacteraceae' in the phylum Bacteroidetes. Phylogenetically, it showed closest similarity (94.0 %) with an uncultured bacterial clone, HP1A92, detected in a sludge microbial community. Among the culturable bacteria, the isolate had highest 16S rRNA gene sequence similarity with Leadbetterella byssophila 4M15T (87.8 %). Sequence similarities with other members of the phylum Bacteroidetes were less than 85 %. The fatty acid profile of the isolate grown on TSBA100 indicated that the major fatty acid was iso-C15:0, which is also present in many members of the family 'Flexibacteraceae'. Cells of strain GPTSA100-15T are Gram-negative, strictly aerobic rods. The DNA G+C content of the isolate is 36.9 mol%. Results of phenotypic, chemotaxonomic and phylogenetic analyses clearly indicate that strain GPTSA100-15T represents a new genus within the family 'Flexibacteraceae'; the name Emticicia gen. nov. is proposed for the genus, with Emticicia oligotrophica sp. nov. as the type species. The type strain of Emticicia oligotrophica is GPTSA100-15T (=MTCC 6937T=DSM 17448T).

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.