halophilic archaeon. It was the only recognized species of the genus Haloquadratum until 1999 when Haloarcula quadrata was reported as recovered from a brine pool. Haloquadratum walsbyi has a unique cellular structure that resembles an almost-perfectly flat-shaped figure.

The genus was first observed in 1980 by British microbiologist Anthony E. Walsby from samples taken from the Sabkha Gavish, a brine lake in southern