gen. nov., sp. nov., gen. nov., sp. nov. and gen. nov., comb. nov., representing the environmental GKS98 (betIII) cluster.

We present two strains affiliated with the GKS98 cluster. This phylogenetically defined cluster is representing abundant, mainly uncultured freshwater bacteria, which were observed by many cultivation-independent studies on the diversity of bacteria in various freshwater lakes and streams. Bacteria affiliated with the GKS98 cluster were detected by cultivation-independent methods in freshwater systems located in Europe, Asia, Africa and the Americas. The two strains, LF4-65 (=CCUG 56422=DSM 107630) and MWH-P2sevCIIIb (=CCUG 56420=DSM 107629), are aerobic chemoorganotrophs, both with genome sizes of 3.2 Mbp and G+C values of 52.4 and 51.0 mol%, respectively. Phylogenomic analyses based on concatenated amino acid sequences of 120 proteins suggest an affiliation of the two strains with the family and revealed and (= ) as being the closest related, previously described species. However, the calculated phylogenomic trees clearly suggest that the current genus represents a polyphyletic taxon. Based on the branching order in the phylogenomic trees, as well as the revealed phylogenetic distances and chemotaxonomic traits, we propose to establish the new genus gen. nov. and the new species sp. nov. to harbour strain LF4-65 and the new genus gen. nov. and the new species sp. nov. to harbour strain MWH-P2sevCIIIb. Furthermore, we propose the reclassification of the species in the new genus gen. nov. The new genera , and together represent taxonomically the GKS98 cluster.