Sperm
The spermatozoa of man survive for five days, but those produced by a small and unknown prehistoric worm now extinct have lasted much longer, as they were found intact by a group of archaeologists of various nationalities in Antarctica only a few months ago and are 50 million years old.
The precise geographical location of the discovery is 'Seymour Island and sperm, produced by the animal almost certainly at the time of mating, it was enclosed in a fossil cocoon which has protected and perfectly preserved it over time.
This is the oldest sperm and spermatozoa found so far.