We don't have synonyms for extremophiles yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are extremophile and extremophilia.
(n) :
(ecology) Any of many organisms that live under extreme conditions of temperature, pressure, salinity, etc; many are autotrophs; some are commercially important as a source of enzymes that operate under similar conditions.
(n) :
(ecology) Any of many organisms that live under extreme conditions of temperature, pressure, salinity, etc; many are autotrophs; some are commercially important as a source of enzymes that operate under similar conditions.