Tag Archives: worm cocoon

Ancient Sperm

19 Jul

Did you know that fossilised sperm found in a worm cocoon from Antarctica has been found to be 50,000,000 years old? The cocoon is the worm’s egg case, created when the worm first secretes a tube around its body and then leaves this tube with sperm and egg inside. The mucus tube hardens, sperm and egg mix, worm embryos are created. This sperm must have been trapped in the cocoon case; the oldest sperm ever found.
This is exceptionally rare; the non-skeletal parts of animals obviously disintegrate. The sperm was found in a tiny piece of cocoon wall, when a routine sediment sample from Antarctica was examined in the Swedish Museum of Natural History. The discovery sheds light on the evolution of the creatures; the fossilised sample looks most like the ‘crayfish worm’, which live on the bodies of freshwater crayfish in the Northern Hemisphere. This suggests that the animals had a much bigger geographical range than they do to day.
The scientists hope that when they examine other fossil cocoons from different parts of the world they may find more trapped sperm or other micro-organisms.
Research into ancient and modern march on together!