Halobellus limi sp. nov. and Halobellus salinus sp. nov., isolated from two marine solar salterns Two halophilic archaea, strains TBN53 T and CSW2.24.4 T , were characterized to elucidate their taxonomic status. Strain TBN53 T was isolated from the Taibei marine solar saltern near Lianyungang city, Jiangsu province, China, whereas strain CSW2.24.4 T was isolated from a saltern crystallizer in Victoria, Australia. Cells of the two strains were pleomorphic, stained Gramnegative and produced

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... gmented colonies. Strain TBN53 T was able to grow at 25-55 6C (optimum 45 6C), with 1.4-5.1 M NaCl (optimum 2.6-3.9 M NaCl), with 0-1.0 M MgCl 2 (optimum 0-0.1 M MgCl 2 ) and at pH 5.5-9.5 (optimum pH 7.0), whereas strain CSW2.24.4 T was able to grow at 25-45 6C (optimum 37 6C), with 2.6-5.1 M NaCl (optimum 3.4 M NaCl), with 0.01-0.7 M MgCl 2 (optimum 0.05 M MgCl 2 ) and at pH 5.5-9.5 (optimum pH 7.0-7.5). Cells of the two isolates lysed in distilled water. The minimum NaCl concentrations that prevented cell lysis were 8 % (w/v) for strain TBN53 T and 12 % (w/v) for strain CSW2.24.4 T . The major polar lipids of the two strains were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and phosphatidylglycerol sulfate, with two glycolipids chromatographically identical to sulfated mannosyl glucosyl diether and mannosyl glucosyl diether, respectively. Trace amounts of other unidentified lipids were also detected. On the basis of 16S rRNA gene sequence analysis, strains TBN53 T and CSW2.24.4 T showed 94.1 % similarity to each other and were closely related to Halobellus clavatus TNN18 T (95.0 and 94.7 % similarity, respectively). Levels of rpoB9 gene sequence similarity between strains TBN53 T and CSW2.24.4 T , and between these strains and Halobellus clavatus TNN18 T were 88.5, 88.5 and 88.1 %, respectively. The DNA G+C contents of strains TBN53 T and CSW2.24.4 T were 69.2 and 67.0 mol%, respectively. The level of DNA-DNA relatedness between strain TBN53 T and strain CSW2.24.4 T was 25 %, and these two strains showed low levels of DNA-DNA relatedness with Halobellus clavatus TNN18 T (30 and 29 % relatedness, respectively). Based on these phenotypic, chemotaxonomic and phylogenetic properties, two novel species of the genus Halobellus are proposed to accommodate these two strains, Halobellus limi sp. nov. (type strain TBN53 T 5CGMCC 1.10331 T 5JCM 16811 T ) and Halobellus salinus sp. nov. (type strain CSW2.24.4 T 5 DSM 18730 T 5CGMCC 1.10710 T 5JCM 14359 T ). Marine solar salterns are artificial hypersaline environments for the production of halite from seawater and harbour diverse halophilic archaea (Burns et al., 2004 ). Recently, increasing numbers of isolates representing novel taxa have been isolated from these habitats, such as Natronomonas moolapensis, Halonotius pteroides (Burns et al., 2010a, b), Haladaptatus litoreus, Halogranum rubrum, Haloplanus vescus, Halopelagius inordinatus, Halosarcina limi, Halogeometricum rufum, 'Halorussus rarus' (Cui et al., 2010a, b, c, d, e, f, g), Halarchaeum Abbreviations: DGD-1, mannosyl glucosyl diether; PG, phosphatidylglycerol; PGP-Me, phosphatidylglycerol phosphate methyl ester; PGS, phosphatidylglycerol sulfate; S-DGD-1, sulfated mannosyl glucosyl diether.