A team of researchers has come across the oldest fossilized sperm samples ever discovered while searching for other things in Antarctica.
Benjamin Bomfleur, researcher at the Museum of Natural History in Stockholm, Sweden, and one of the lead authors of the study, explained that the sperm samples they found belong to a species of worm known as clitellate annelid from a group of leeches and earthworms. The worm also had some features in common with the crayfish worm.
Bomfleur said that it’s very difficult to make a detailed comparison between the prehistoric worm and its living modern leech relative. However, the researchers found that it’s very similar to a species that belongs to the Branchiobdellida family. This is a group of worms that resemble leeches, that lives in a symbiotic relationship with the crayfish on the Northern Hemisphere. Bomfleur said he is very surprised by the recent discovery and wasn’t expecting it at all.
Bomfleur stated that a Jurassic Park-like experiment would not be possible because even though the DNA is well preserved, there aren’t any traces of organic material inside the 50-million-year old fossilized sperm.
According to the researchers, the chemical composition of the sperm’s organic material has undergone many changes over millions of years of fossilization. That’s why scientists would not be able to extract the DNA and recreate the prehistoric creature in the laboratory.
The scientists published their findings in the journal the Royal Society Biology Letters
The plaeobiologists discovered the 50-million-year old fossilized sperm in the La Meseta Formation, in the Seymour/Marambio Island on the Antarctic Peninsula. According to them, they made the discovery by mere accident as they were involved in a different project studying the fossils to better understand how the cocoon was created.
They were very surprised to discover the fossilized sperm traces, and Bomfelur said it was all thanks to a very detailed research and his colleague Stepehen McLoughlin’s attention for details. The researchers said they were aware of the fact that they should analyze the cocoon because it could contain valuable “microinclusions” in which important data was preserved. As they were analyzing the cocoon’s structure using a special technology called electron microscopy, the scientists noticed the inclusions of spermatozoa.
The researchers say the new discovery will help them better understand the evolution of micro-organisms, especially since there isn’t much fossil data in this particular field.
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