An extremely halophilic archaeon, strain IC35T was isolated from a mud sample of the Aran-Bidgol salt lake in Iran. The novel strain was cream pigmented, non-motile rod shaped and required at least 2.5 M NaCl but not MgCl2 for growth. Optimal growth was achieved at 3.4 M NaCl and 0.1 M MgCl2. The optimum pH and temperature for growth were pH 7.0 and 40 °C, respectively, while it was able to grow over a pH range of 6.5-9.0 and a temperature range of 30-50 °C. Analysis of 16S rRNA gene sequence revealed that strain IC35T clustered with the species of the genus Halovivax; Halovivax limisalsi IC38T, Halovivax asiaticus EJ46T and Halovivax ruber XH-70T with a sequence similarity of 97.3 %, 96.6 % and 96.3 %, respectively. The rpoB′ gene similarity between the novel strain and Halovivax limisalsi IBRC-M10022T, Halovivax ruber JCM 13892T and Halovivax asiaticus JCM 14624T were 90.2 %, 90.2 % and 89.9 %, respectively. The polar lipid pattern of strain IC35T consisted of phosphatidylglycerol and phosphatidylglycerol phosphate methyl ester. Six undetermined glycolipids and two minor phospholipids were also observed. The only quinone present was MK-8(ΙΙ-H2). The G+C content of its DNA was 63.2 mol%. DNA-DNA hybridization studies (29.3 % with Halovivax limisalsi IBRC-M 10022T), as well as biochemical and physiological characterization, allowed strain IC35T to be differentiated from other species in the genus Halovivax. A novel species Halovivax cerinus sp. nov., is therefore proposed to accommodate this strain. The type strain is IC35T (= IBRC-M10256T = KCTC 4050T).

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