An extremely halophilic archaeon belonging to the order Halobacteriales was isolated from Fuente de Piedra salt lake, Spain. This strain, designated FP1 T , was a pleomorphic coccoid, neutrophilic and required at least 15 % (w/v) NaCl for growth. Strain FP1 T grew at 37–60 °C, with optimal growth at 50 °C. Mg 2+ was not required, but growth was observed with up to 10 % (w/v) MgSO 4 . Polar lipid analysis revealed the presence of mannose-6-sulfate(1-2)-glucose glycerol diether as a major glycolipid. Both C 20 C 20 and C 20 C 25 core lipids were present. The genomic DNA G+C content was 62.0 mol%. Phylogenetic analysis based on comparison of 16S rRNA gene sequences demonstrated that the isolate was most closely related to species of the genus Haloterrigena . DNA–DNA reassociation values between strain FP1 T and the most closely related species of the genus Haloterrigena ( Haloterrigena thermotolerans , Haloterrigena saccharevitans and Haloterrigena limicola ) were lower than 29 %. It is therefore considered that strain FP1 T represents a novel species of the genus Haloterrigena , for which the name Haloterrigena hispanica sp. nov. is proposed. The type strain is FP1 T (=DSM 18328 T =ATCC BAA-1310 T ).