"Guinness World Records recognizes Nanoarchaeum equitans as the smallest living organism." Wikipedia
The smallest form of life that is generally accepted as a living organism is Nanoarchaeum equitans. It is a single-celled archaeon that is about 400 nanometers in diameter. It was first discovered in 2000 in a hot spring in Iceland. Nanoarchaeum equitans is a parasite that lives on the surface of another archaeon called Ignicoccus. It is thought to be the smallest free-living organism on Earth.
However, there are some scientists who believe that there are even smaller organisms that exist. These organisms are called "nanobes" and they are thought to be about 100 nanometers in diameter. Nanobes have not been definitively identified, but some scientists believe that they may be the earliest form of life on Earth.
Ultimately, the question of what is the smallest form of life is a matter of definition. There is no clear consensus on what criteria an organism must meet in order to be considered alive. However, Nanoarchaeum equitans is the smallest organism that is generally accepted as a living organism.
