A novel halophilic archaeon, strain BZ256T, was isolated from Zodletone Spring, a sulfide- and sulfur-rich spring in south-western Oklahoma, USA. Cells were non-motile, non-flagellated cocci that divided along two axes, resulting in the formation of sarcina-like clusters. Strain BZ256T grew at salt concentrations ranging from 1.3 to 4.3 M NaCl, with optimum growth at approximately 3.4 M, and required at least 1 mM Mg2+ for growth. The pH range for growth was 5.0 to at least 8.5, and the temperature range for growth was 25-45 degrees C. The two diether phospholipids that are typical of members of the order Halobacteriales, namely phosphatidylglycerol and phosphatidylglycerol phosphate methyl ester, were present in strain BZ256T, as were two glycolipids chromatographically identical to S-DGD-1 and DGD-1. The 16S rRNA gene sequence of strain BZ256T showed 96.8 % similarity to that of the type strain of Halogeometricum borinquense, the closest recognized species within the order Halobacteriales. The DNA G+C content of strain BZ256T was 65.4 mol%. Microscopic, physiological, biochemical and phylogenetic comparisons between strain BZ256T and recognized genera of extremely halophilic archaea suggest that this strain represents a member of a novel genus and species within the family Halobacteriaceae, for which the name Halosarcina pallida gen. nov., sp. nov. is proposed. The type strain of Halosarcina pallida is BZ256T (=KCTC 4017T =JCM 14848T).