Greetings, people of OA

[Worldtree]

Thank you for the information; I was referring more to the maximum temperature of lifeforms based on something similar to traditional biochemistry (proteins, etc.). Still, the page you linked was very interesting and informative.

http://www.bbc.com/earth/story/20160209-...ilin-water

the hottest temperatures we -know- organic, water-soluble life can exist in would be right below boiling temperature 100 C

Conditions are so challenging that no complex organisms can survive them. Animals generally struggle when they are exposed to temperatures much above 50C – true even of the Pink Pompeii worms that live next to deep-sea hydrothermal vents spewing out water at 400C onto the ocean floor.
Desulfurella acetivorans, for instance, is a bacterium that thrives in pools at 58C. It feeds on organic acetate in the pool. Rather than breathing oxygen, these microbes get their energy from volcanic sulphur through a process known as sulphur reduction.

Then there is Thermoproteus uzoniensis. This new species of archaea was found thriving in the hot springs, steam vents, mud holes and soils in the Uzon Caldera and Geyser Valley.
The rod-shaped microbes can survive in waters close to boiling point by feeding on the fermented remains of organic molecules called peptides. They also use sulphur reduction for energy. Scientists believe that strains of closely related T. uzoniensis are so common across the region because they are being carried between pools by wind, water, birds or even bears.
Acidilobus aceticus is so named because of the extreme acidity – pH2 – of the hot spring in which it was found. The acidic water was also very hot, at 92C. The microbe feeds on fermented starch and, again, uses sulphur to power its metabolism.

as for in Orions arm,
there's probably some extremophile clades or tweaks which aren't described yet in detail AFAIK- though clades adapted to a vacuum environment can probably withstand higher temperatures 

To'ul'h has a lot of organisms that we'd consider extremophiles living in a high temperature environment as well
https://www.orionsarm.com/eg-article/48f71d38d2c56