BERLIN: A team of palaeontologists have discovered what they believe is the world’s oldest animal sperm, frozen in tree resin 100 million years ago inside a tiny crustacean in Myanmar.

The oldest known examples of fossilised animal sperm were previously a mere 17 million years old, according to the team of experts led by Wang He of the Chinese Academy of Science in Nanjing.

The sperms were found inside an ostracod — a type of crustacean that has existed for 500 million years and can be found in many oceans today, they said in a paper published on Wednesday in the Royal Society’s Proceedings journal.

They were found in the body of a female specimen, indicating that she must have been fertilised shortly before being trapped in amber, the experts said.

The individual sperms were described as “giants”, measuring up to 4.6 times the size of the body of the male.

“This is equivalent to about 7.30 metres (24 feet) in a 1.70-metre human, so it requires a lot of energy to produce them,” Renate Matzke-Karasz of the Ludwig Maximilian University of Munich, co-author of the study, said. The ostracod was also a new species that the scientists have named “Myanmarcypris hui”.

Fossilised shells of ostracods are common but finding a specimen with “soft parts” is rare, the experts said.

During the Cretaceous period around 145 to 66 million years ago, the ostracods in question probably lived in the coastal waters of present-day Myanmar where they became trapped in a blob of tree resin.

The specimen was handed over to researchers by a Chinese collector in 2017.

The tiny creatures are less than a millimetre long but the scientists made 3-D reconstructions of them to observe them more closely, leading to what Wang described as “one of those special Eureka moments in a researcher’s life”.

Published in Dawn, September 17th, 2020