A fire amoeba raises the eukaryotic heat ceiling to 63°C

Researchers isolated Incendiamoeba cascadensis from hot springs in California's Lassen Volcanic National Park. It undergoes mitosis at 63°C, above the previous 60°C reproduction record held by a few fungi and red algae; it still moves at 64°C and can recover after brief exposure to 70°C. Its genome is enriched for mechanisms tied to protein homeostasis, genome stability and environmental sensing. It remains a single-celled amoeba, so the record does not imply that humans or other complex organisms can tolerate the same heat, but it expands the known boundary of eukaryotic life.