50-million-year-old fossil sperm discovered
World’s oldest sperm may have come from a leechlike worm
![ancient sperm](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2015/07/mr_oldestsperm_free.jpg?fit=860%2C460&ssl=1)
ANCIENT SPERM The elongated head and whiplike tail of one of many apparent worm sperm cells studs the wall of a 50-million-year-old cocoon.
B. Bomfleur et al/Biology Letters 2015