Halomonas borealis sp. nov. and Halomonas niordiana sp. nov., two new species isolated from seawater.

Two Gram-negative strains obtained from tank water in a scallop hatchery in Norway, were phenotypically and genotypically characterized in order to clarify their taxonomic position. On the basis of 16S rRNA gene sequence analysis, these isolates, ATF 5.2 and ATF 5.4, were included in the genus Halomonas, being their closest relatives H. smyrnensis and H. taeanensis, with similarities of 98.9% and 97.7%, respectively. Sequence analysis of the housekeeping genes atpA, ftsZ, gyrA, gyrB, mreB, rpoB, rpoD, rpoE, rpoH, rpoN and rpoS clearly differentiated the isolates from the currently described Halomonas species, and the phylogenetic analysis using concatenated sequences of these genes located them in two robust and independent branches. DNA-DNA hybridization (eDDH) percentage, together with average nucleotide identity (ANI), were calculated using the complete genome sequences of the strains, and demonstrate that the isolates constitute two new species of Halomonas, for which the names of Halomonas borealis sp. nov. and Halomonas niordiana sp. nov. are proposed, with type strains ATF 5.2 (=CECT 9780=LMG 31367) and ATF 5.4 (=CECT 9779=LMG 31227), respectively.