Fossils from a tiny shrimp have revealed they had giant sperm longer than the male’s body

Specimen of the modern Australian ostracod Newnhamia fenestrata with the right valve removed. Picture: R. Matzke-Karasz Source: Supplied

GIANT fossilised shrimp sperm has been discovered by a team that includes Australian researchers at a World Heritage Fossil site in remote Queensland.

Coming from tiny shrimps that lived over 17 million years ago, the sperm are said to be the oldest ever found in the geological record.

Sketch of a male ostracod, showing the organization and orientation of the reproductive system. Picture: R. Matzke-Karasz Source: Supplied

C. Scanning electron microscopic image of Riversleigh fossil ostracod seen from the left side, with left valve partly missing. d. Virtual reconstruction of fossil showing one of two Zenker organs. e. Details of fossil Zenker organ, e.g. chitinous rings (cr) around the central tube and chitinous spines (cs). Picture: a, c-g: R. Matzke-Karasz Source: Supplied

Thought to have been longer than the male’s entire bodies, the sperm was found tightly coiled up in the freshwater crustaceans’ sexual organs.

UNSW School of Biological, Earth and Environmental Sciences Professor Mike Archer said the discovery was totally unexpected.

Skull fossil of flesh eating kangaroo discovered by team of University of New South Wales researchers as part of three new deposits at the World Heritage Riversleigh fossil fields in Queensland. Picture: AP Source: AP

“The Riversleigh fossil deposits in remote north-western Queensland have been the site of the discovery of many extraordinary prehistoric Australian animals, such as giant, toothed platypuses and flesh-eating kangaroos — so we have become used to delightfully unexpected surprises in what turns up there,” Professor Archer said.

The Riversleigh giant carnivorous, toothed platypus, Obdurodon tharalkooschild, tenderizing a young short-necked tortoise, on the edge of a quiet pool in the lush forests that once dominated the area. The powerfully-built tooth of Obdurodon tharalkooschild shown in the inset is vastly different than the vestigial, dysfunctional teeth of the living Platypus. Source: Supplied

“The discovery of fossil sperm, complete with sperm nuclei, was totally unexpected. It now makes us wonder what other types of extraordinary preservation await discovery in these deposits.”

The study is published in the journal Proceedings of the Royal Society B.

THe Bitesantennary Site at Riversleigh World Heritage Fossil Site where 17 million year old fossil sperm were found and surrounding site. The ancient cave site is ringed in red, with UNSW’s Associate Professor Suzanne Hand in blue shirt. Picture: UNSW Source: Supplied