Two extremely halophilic archaeal strains, GSLN9 and XZYJT29 , were isolated from the saline soil in different regions of western China. Both strains GSLN9 and XZYJT29 have two 16S rRNA genes with similarities of 95.1 and 94.8 %, respectively. Strain GSLN9 was mostly related to the genus based on 16S rRNA (showing 91.0-96.0 % identities) and genes (showing 92.0 % identity). Strain XZYJT29 showed 92.1-97.6 % (16S rRNA gene) and 91.4-93.1 % ( gene) sequence similarities to its relatives in the genus , respectively. The polar lipid profile of strain GSLN9 included phosphatidic acid (PA), phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me), phosphatidylglycerol sulphate (PGS), sulphated mannosyl glucosyl diether (S-DGD-1) and sulphated galactosyl mannosyl glucosyl diether (S-TGD-1), mostly similar to that of H22 . PA, PG, PGP-Me, S-DGD-1 (S-DGD-PA), S -DGD, S-TGD-1 and an unidentified glycolipid were detected in strain XZYJT29 ; this polar lipid composition is similar to those of members of the genus . The average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity values between these two strains and their relatives of the genera and were no more than 82, 27 and 80 %, respectively, much lower than the thresholds for species demarcation. Other phenotypic characterization results indicated that strains GSLN9 and XZYJT29 can be differentiated from the current species of the genera and , respectively. These results revealed that strains GSLN9 (=CGMCC 1.15215 =JCM 30842 ) and XZYJT29 (=CGMCC 1.15828 =JCM 31853 ) represent novel species of and , for which the names sp. nov. and sp. nov. are proposed.