Scientists have found the oldest sperm ever discovered, and they are whoppers. They belong to a type of tiny crustacean called an Ostracod. The finding suggests that Ostracods evolved their gargantuan gametes far earlier than their rivals in the supersize sperm leagues, the fruit flies. http://www.nature.com/news/giant-sperm-found-in-crustacean-fossils-1.15218
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