Thermophilic ostracod: aquatic metazoan with the highest known temperature tolerance.

The upper lethal temperature for an ostracod of the genus Potamocypris collected from a thermal stream ranged from 49 degrees C for incubation of more than 5 hours to 55.75 degrees C for 1-minute incubations. Field collections were held at 35 degrees C for less than 24 hours before experimental incubations. Calculated temperatues for 50 percent mortality for 60, 40, 20, 10, 5, and 1 minute of exposure were 50.44 degrees , 50.96 degrees , 51.43 degrees , 52.03 degrees , 52.77 degrees , and 55.12 degrees C, respectively.