World’s oldest known animal identified after decades-long mystery

Rodiano Bonacci
Сентября 22, 2018

"The fossil fat now confirms Dickinsonia as the oldest known animal fossil, solving a decades-old mystery that has been the Holy Grail of palaeontology", Brocks continued.

The research has been published in the journal Science.

Dickinsonia came from a period known as the Ediacaran, which spanned about 94 million years from the end of the Cryogenian Period to the beginning of the Cambrian Period 541 Mya.

The decades-long mystery surrounding a creature that lived on Earth over half a billion years ago has finally been settled, thanks to fossils found in Russian Federation which are so well preserved they still contain fat molecules.

"I took a helicopter to reach this very remote part of the world - home to bears and mosquitoes - where I could find Dickinsonia fossils with organic matter still intact", he added.

Mr Bobrovskiy said the team developed a new approach to study Dickinsonia fossils, which hold the key between the old world dominated by bacteria and the world of large animals that emerged 540 million years ago during the "Cambrian explosion".

A new study has revealed that the earliest confirmed animal in the geological record lived 558 million years ago.

"The fossil fat molecules that we've found prove that animals were large and abundant 558 million years ago, millions of years earlier than previously thought", said Associate Professor Jochen Brocks from the ANU Research School of Earth Sciences.

Dickinsonia is part of the Ediacaran biota, a class that includes other soft-bodied organisms similar to jellyfish, sea anemones, or worms.

Most of the Dickinsonia fossils were found in the Ediacara Hills in Australia, and have been subjected to tremendous heat, pressure and weathering, leaving no organic matter behind. It looks rather like a leaf.

By identifying specific biomarkers preserved alongside fossils of oval-shaped life forms from the Ediacaran Period, fossils from which are typically considered one of the greatest mysteries in paleontology, researchers say the ovular organism is not a fungus or protist, as some have thought, but an early animal. "I had to hang over the edge of a cliff on ropes and dig out huge blocks of sandstone, throw them down, wash the sandstone and repeat this process until I found the fossils I was after", said Ilya Bobrovskiy, an Australian researcher who discovered the fossil.

"These fossils were located in the middle of cliffs of the White Sea that are 60 to 100 metres high".

Bobrovskiy then developed a special technique to test the Dickinsonia remnants for cholesterol.

ANU researcher Ilya Bobrovskiy searches for fossils in the Zimnie Gory locality, Russia.

As soon as Bobrovskiy showed the findings to Brocks, he immediately realized what he saw, noting they were a game changer and he "immediately saw the significance". And, since animals are the only organisms capable of producing cholesterol, they argue that the molecules offer definitive evidence of Dickinsonia's status.

"There's a lot of uncertainty", Bobrovskiy said of studying such ancient life.

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