A team of paleontologists have discovered what they believe is the world’s oldest animal semen, frozen inside a small crustacean in a blob of wood resin in Myanmar 100 million years ago.
The oldest known examples of fossilized animal semen were previously only 17 million years old, according to the team of experts led by Wang He of the Chinese Academy of Sciences in Nanjing.
The semen was found inside an ostracod, 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 Royal Society̵
They were found in the body of a female specimen, indicating that she must have been fertilized shortly before she was trapped in the wood resin, experts said.
To make the finding even more special, the sperm were also described as “fighting”, measuring up to 4.6 times the size of the man’s body.
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“This equates to about 7.30 meters in a 1.70 meter human, so it takes a lot of energy to produce them,” Renate Matzke-Karasz of Ludwig Maximilian University in Munich, co-author of the study, told AFP.
The ostracode was also a new species that scientists have called the “Myanmarcypris hui”.
Quality over quantity
Fossilized shells of ostracods are common, but it is rare to find a sample with “soft parts”, experts say.
In the Cretaceous (about 145 to 66 million years ago), the ostriches in question probably lived in the coastal waters of present-day Myanmar, where they were caught in a blob of woody resin.
Most men in the animal kingdom (including humans) generally produce tens of thousands of tiny sperm cells, but for ostracodes, it’s about quality rather than quantity.
There are several conflicting theories about the evolutionary value of such 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 led to a longer sperm life,” Matzke-Karasz said. .
This discovery shows “that reproduction with giant sperm is not an evolutionary extravagance on the verge of extinction, but a serious long-term benefit to a species’ survival,” Matzke-Karasz concluded.