strains of "vulcanisaeta" were found in hot spring areas in japan. despite the organisms being the most common rod-shaped crenarchaeote among isolates from hot springs in japan, it has not isolated from other countries. this contrasts with the genera "thermoproteus" and "pyrobaculum", which are distributed worldwide, including the azores, iceland, indonesia, italy, japan, the philippines, russia, and the united states. therefore, it is possible that the genus "vulcanisaeta" has a restricted distribution that includes japan.