Two extremely halophilic archaeal strains, designated TNN44(T) and TNN58(T), were isolated from Tainan marine solar saltern near Lianyungang city, Jiangsu province, China. Cells of the two strains were pleomorphic and Gram-stain-negative; colonies were red-pigmented. Strains TNN44(T) and TNN58(T) were able to grow at 20-50 °C (optimum 37 °C for both), in the presence of 1.4-5.1 M NaCl (optimum 3.4-3.9 M NaCl) and at pH 5.5-9.0 (optimum pH 6.5-7.0); neither strain required Mg(2+) for growth. Cells lysed in distilled water. On the basis of 16S rRNA gene sequence analysis, strains TNN44(T) and TNN58(T) were related closely to Halogranum rubrum RO2-11(T) (96.2 and 97.2 % similarity, respectively). The polar lipids of the two strains were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate (trace), and one major glycolipid and one minor glycolipid chromatographically identical to sulfated mannosyl glucosyl diether and mannosyl glucosyl diether, respectively; other trace unidentified lipids were also detected. The DNA G+C content of strains TNN44(T) and TNN58(T) was 64.0 and 62.0 mol%, respectively. The level of DNA-DNA relatedness between strains TNN44(T) and TNN58(T) was 37.2 %, and these two strains showed a low level of DNA-DNA relatedness with Halogranum rubrum RO2-11(T) (40.6 and 44.4 %, respectively). Two novel species of the genus Halogranum are proposed to accommodate these two strains, Halogranum gelatinilyticum sp. nov. (type strain TNN44(T) = CGMCC 1.10119(T) = JCM 16426(T)) and Halogranum amylolyticum sp. nov. (type strain TNN58(T) = CGMCC 1.10121(T) = JCM 16428(T)).