Three strains isolated from Northern Germany constitute the novel genera Njordella and Rania in the family Pirellulaceae.

This study reports the characterization of three novel species belonging to the two newly established genera Njordella gen. nov. and Rania gen. nov. in the family Pirellulaceae within the phylum Planctomycetota. The three investigated strains SH302T, SH451T and SH573T were isolated from water samples originating from distinct locations across Northern Germany: Lägerdorf (a municipality close to Hamburg), Fjord Schlei (a 42 km estuary of the Baltic Sea) and Fehmarn Island in the Baltic Sea. All strains form (light) pink colonies, reproduce asymmetrically by polar budding and display an acorn-shaped cell morphology typical in the family Pirellulaceae. Rosette formation was only observed for strains SH302T and SH573T. The three strains are mesophilic with a temperature optimum at 28 °C, aerobic and heterotrophic, but differ in their pH preference. While strains SH302T and SH573T are neutrophilic (pH optimum at 7.0 and 7.5, respectively), strain SH451T is slightly alkaliphilic (optimal growth at pH 8.0). The genome sizes of strains SH302T, SH451T and SH573T are 7.2 Mb, 6.6 Mb and 9.4 Mb, respectively. Based on phylogenetic, morphological and physiological analyses, we conclude that the novel strains belong to three novel species of two novel genera. For the novel taxa, we introduce the names Njordella aestuarii gen. nov., sp. nov., represented by strain SH451T (= CECT 30907T = KCTC 102089T) as the type strain and Njordella calcicola sp. nov. with type strain SH302T (= DSM 116728T = KCTC 102091T). For the third taxon, we chose the name Rania fehmarnensis gen. nov., sp. nov. represented by the type strain SH573T (= DSM 116763T = CECT 31080T = KCTC 102135T).