A “fire amoeba” divided at 63°C, raising the heat record for eukaryotes

Incendiamoeba cascadensis grew best at 55–57°C and still completed cell division at 63°C.

It moved at 64°C but stopped dividing; after five minutes at 70°C it recovered when cooled, while exposure to 80°C was fatal.

Why 63°C is a record

Eukaryotes have a nucleus and internal cellular machinery. The previous growth ceiling was about 60°C in some fungi and red algae, so the result raises the replication limit rather than merely showing survival.

How it copes remains incomplete

Positively charged protein surfaces and membrane chemistry may improve heat stability. Experiments must still identify which changes are essential and whether close relatives share them.

Do not jump straight to alien life

Temperature alone does not make a habitat. Acidity, oxygen, pressure, water, food and an ecosystem also matter, and Earth remains the only world known to host life.

What comes next

Related DNA appears in geothermal datasets from New Zealand and Yellowstone, but living cells have not been isolated there. Cultures and functional tests will define the record’s range and evolution.

Primary source and independent checks

Primary source: Cell paper

Institutional explanation: NASA Science

Independent check: Science News independent report

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