Paleontologists have recently discovered what is now termed as the oldest sample of animal sperm, concealed in a 100 million-year-old piece of amber.
The sample was found in the reproductive tract of an ancient female crustacean encased in resin — one of several samples of ostracods from Myanmar.
Previously an unknown species of crustacean, now named Myanmarcypris hui, it resembles a modern day mussel and is an example of an ostracod.
Ostracods are small animals that date back some 500 million years, and can still be found in oceans, freshwater lakes and rivers.
According to CNN, using 3D X-ray reconstructive technology, scientists analyzed several ostracod specimens, studying their limbs and reproductive organs.
Experts discovered ripe sperm inside the sperm receptacles of a female crustacean, who would have stored the sperm for release once her eggs had matured had she not been encased in the sticky tree resin.
He Wang, from the Chinese Academy of Sciences in Nanjing, in a statement reportedly said the female must have been encased or trapped in the resin shortly after mating.
Scientists said the discovery marks the oldest fossil in which sperm cells have been conclusively identified.
In findings published in the Royal Society journal on Wednesday, the report authors said the tests have discovered that the new results “double the age of the oldest unequivocal fossil animal sperm”.
The report Authors say specimens of fossilized sperm are very rare, revealing that the oldest known ostracod sperm are 17 million years old, and the previous record age of 50 million years was held by a species of worm.
The discovery provides groundbreaking insights into an unexpectedly ancient and advanced instance of evolutionary specialization, the report scientists said.
Researchers added that the evidence of use of giant sperm 100 million years ago is proof of a successful long term reproductive strategy.
“The complexity of the reproductive system in these specimens raises the question of whether the investment in giant sperm cells might represent an evolutionarily stable strategy,” Renate Matzke-Karasz, a geobiologist at Ludwig-Maximilians-Universitaet in Munich who was involved in the morphological analysis of the specimens, said in a statement.