Prokaryotes are by far the most successful superkingdom in terms of both biochemical diversity and the variety of environments conquered. Bacteria can be found living in all kinds of adverse conditions; from high alkaline lakes, to below freezing temperature, to hot volcanic vents which in some cases can reach temperatures close to the boiling point of water.
Thermotoga is a small genus of bacteria that contains some of the most hyperthermophilic species known, some able to survive at 90°C although most prefer the cooler temperatures of 70-80°C. It’s called “thermotoga” because it lives at high temperatures (thermo) and contains a characteristic outer cell membrane known as the ‘toga’.
Click "source" to read more.