Based on 16s rRNA sequences, the genus Haloferax is most closely related to the genus Halogeometricium. Though most species of Haloferax are extremely halophilic, most are also pleomorphic and do not require salt levels as high as other halophiles for growth. Haloferax denitrificans was first isolated from salterns in San Francisco Bay. The cells are Gram-negative, nonmotile, and aerobic. They have been observed to grow between 1.5M and 4.5M NaCl and lyse in distilled water.