Have you ever seen a sperm? Well with a microscope you can see them swimming. Researchers have discovered the world’s oldest fossilized sperm entrapped in the wall of a fossilized worm cocoon in Antarctica. The researchers claim that it dates back to 50million years.
Sperms are rare to find in the fossil record because they are very delicate and have a short life span. Benjamin Bomfleur, lead author of the study, and his research team accidentally came across the incredible find during their expedition in Antarctica. Benjamin Bomfleur and his team are still analyzing the fragments to get a better idea of the structure of the cocoon.
“When we zoomed into the images, we started noticing these tiny biological structures that look like sperm,” he explained.
The research team from Sweden, Italy and Argentina used a scanning electron microscope to look at the specimen’s surface. They also used a particle accelerator in Switzerland to examine the internal structure of the cocoon, which revealed the presence of the sperm cell fragments from a 50-million-year-old Clitellata.
“The ancient worm is thought to have secreted the cocoon while mating. Egg and sperm was then released into the cocoon and protected by the surrounding material. The cocoon finally sealed it and hardened trapping the biological materials on the walls.” The researchers suggest. That is how the sperm fossil was able to form and be preserved for millions of years, similar to how amber traps and preserves insect and plant materials over millions of years.
“All we found are fragments of the drill-bit-shaped ‘head regions,’ ornamented midpiece regions that presumably contain the nuclei, and very long, whip-like tails, some attached to the midpiece regions,” Bomfleur said.
Ifl science reports that this specimen is 10 million years older than the next oldest known fossilized sperm. Bomfleur explained that the fossilized remains don’t contain any original organic material.
“The sperm fragments are similar to that of a group of leech-like worms found on the shells of modern crayfish in the Northern Hemisphere where they feed on dead organic matter.” The researchers said. Further studies on the cocoon could reveal a great deal of information which, according to Bomfleur, has been overlooked by paleontologists who tend to focus on relatively hard structures like bones and shells.