A team of paleontologists has discovered what they believe to be the world’s oldest animal sperm, frozen inside a tiny crustacean in a layer of tree resin in Myanmar 100 million years ago.
According to the expert team led by Wang He of the Chinese Academy of Sciences in Nanjing, the earliest known examples of fossilized animal sperm were previously only 17 million years old.
Sperm were found inside an oyster code, a species of crustacean that has existed for 500 million years and can be found in many oceans today, researchers said in a paper published Wednesday in the prestigious journal Proceedings of the Royal Society.
Experts noted that they were found in the body of a female species, indicating that it should be fertilized shortly before it is trapped in the resin of the tree.
To make the finding even more special, sperm were also described as “giants,” measuring up to 4.6 times the size of the male’s body.
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“This equates to about 7.30 meters in a 1.70-meter human, so it requires a lot of energy to produce them,” Renate Matzke-Karasz of Ludwig Maximilian University in Munich, co-author of the study.
Ostracode was also a new species that scientists have called “Myanmarcypris hui”.
Quality over quantity
Fossilized ostracode shells are common, but it is rare to find a specimen with “soft parts,” according to experts.
During the Cretaceous period (about 145 to 66 million years ago), the ostracods in question probably lived in the coastal waters of present-day Myanmar, where they were trapped in a resin ball of trees.
Most males in the animal world (including humans) generally produce tens of millions of tiny sperm cells, but for ostracods, it’s about quality over quantity.
There are several contradictory theories about the evolutionary value of these giant sperm.
“For example, experiments have shown that in one group, a high degree of competition between men can lead to a longer sperm life, while in another group, a low degree of competition also leads to a longer life. longer than sperm, ”Matzke-Karasz said.
This finding shows “that reproduction with giant sperm is not an evolutionary extravaganza on the verge of extinction, but a serious long-term advantage for the survival of a species,” Matzke-Karasz concluded.