A motile, rod-shaped, pink-pigmented, extremely halophilic archaeon, strain SF3-213(T), was isolated from a crystallizer pond at the Cargill Solar Salt Plant, Newark, California (USA). Analysis of the almost-complete 16S rRNA gene sequence showed that the isolate was phylogenetically related to species of the genus Halorubrum, with a close relationship to Halorubrum trapanicum NRC 34021(T) (98.6 % similarity), Halorubrum sodomense ATCC 33755(T) (98.3 %) and Halorubrum xinjiangense AS 1.3527(T) (98.2 %). The polar lipids of strain SF3-213(T) were C(20)C(20) derivatives of phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate and a sulfated diglycosyl-diether. Strain SF3-213(T) grew in 2.5-5.0 M NaCl. The temperature and pH ranges for growth were 25-42 degrees C and 6.8-8.5, respectively. Optimal growth occurred at 3.5-4.5 M NaCl, 37 degrees C and pH 7.3. Mg(2+) was required for growth. The DNA G+C content was 69.4 mol%. DNA-DNA hybridization values lower than 70 % were obtained between strain SF3-213(T) and the closely related species of the genus Halorubrum. Based on the data presented in this study, strain SF3-213(T) represents a novel species for which the name Halorubrum californiense sp. nov. is proposed; the type strain is SF3-213(T) (=CECT 7256(T)=DSM 19288(T)=JCM 14715(T)).