World first ancient fossil discovery

La Trobe scientist finds preserved sperm in a shrimp more than 16 million years old.

In a world first, Research Associate John Neil, who works out of the Bendigo campus of the University says the finding marks a breakthrough in tracking the evolution of the shrimp or ostracod – a tiny non-marine crustacean found in fresh water.

He said the perfectly preserved condition of the ancient shrimp has allowed scientists to compare the creature of the past with how it is today and very little has changed.

'This finding shows us that an organism as complex as the ostracod has changed very little in over 16 million years. Our ancient ostracod has almost an identical structure and organs to ostracods today. This find provides accurate information on the organism's evolutionary status,' he said.

The fossil, one of five recovered by Mr Neil, originated from Australia's most famous fossil site, the Riversleigh region in northern Queensland.

Its discovery is an exercise in interstate and global teamwork.

Professor Michael Archer from the University of NSW has been overseeing the excavation of ancient fossils at the site for years and passed on some of the ostracods to Mr Neil to utilize his skills as a taxonomist.

'The calcium carbonate microfossils in the area are rare because they have been changed by the soft freshwater limestone which allows for better preservation of the animal remains.

'The sperm and its sub-cellular structure is believed to be the oldest and best preserved on record and is very large relative to the size of the animal.

'Relatively speaking the size of the sperm coiled tightly in this tiny animal would equate to a human sperm the length of a cricket pitch,' he said.

Once Mr Neil identified the initial soft-part preservation of the fossils, an international team of experts carried out synchrotron work to obtain the amazing miniscule details of the creature's make up.

The intricate identification of the ostracods' organs, which includes vision of the sperm nucleus has been carried out by a team working at the European Synchrotron Radiation Facility in Grenoble, France.

The project leader there is Dr Renate-Matzke-Karasz of the Ludwig-Maximiliaen University in Munich, Germany.

The findings have been published in the prestigious Journal Proceedings of the Royal Society B.

Read John Neil's interview with The Age.

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