picrophilaceae picrophilaceae in taxonomy, the picrophilaceae are a family of microbes within thermoplasmatales. picrophilaceae scientific classification domain: archaea kingdom: euryarchaeota phylum: euryarchaeota class: thermoplasmata order: thermoplasmatales family: picrophilaceaeschleper et al. 1996 genus picrophilus morphology and ecology the cells are round in shape, thermophilic, heterotrophic, and obligately aerobic. this species is hyperacidophilic, with an optimal ph of 0.7. its optimal temperature is 60 °c. it has been isolated from fumaroles, acidic sediments, dry solfataric fields, and hot springs in hokkaidō, japan.