At 558 million years it is the oldest land animal ever discovered: a research team led by scientists from the Australian National University found fat residues in an ancient fossil called Dickinsonia, proving that this could not be anything other than an animal
At 558 million years it is the oldest land animal ever discovered: a research team led by scientists from the Australian National University found fat residues in an ancient fossil called Dickinsonia, proving that this could not be anything other than an animal.
The creature grew to 1,4 meters in length, was oval in shape with rib-like features running along its body, and lived on Earth 20 million years before the so-called "Cambrian explosion," that short period (on a scale geological) in which most of the animals appeared on the planet.
The research team found the truly incredible "elder" in a remote area near the White Sea in northwestern Russia, so well preserved that the tissue still contained molecules of cholesterol, a type of fat typical of animal life.
“The fossil fat molecules we found show that animals were large and abundant 558 million years ago, millions of years earlier than previously thought,” explains Jochen Bobrovskiy, co-author of the paper.
And there is more: with this incredible discovery not only could the arrival of animals on our planet be “re-established”, but a milestone has been set on Dickinsonia itself, whose nature has long been the subject of disputes.
Scientists have been debating for over 75 years what Dickinsonia and other bizarre fossils were: giant unicellular amoebas, lichens, failed evolution experiments, or the first animals on Earth. Fossil fat confirms this as the oldest known animal fossil".
And all thanks to the development of a new approach for the study of the Dickinsonia fossils, which represent 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.
For many decades, in fact, the researchers still explain, studies have focused on the rocks where the fossil was "embedded", but many of these have undergone heat, pressure, and have been subjected to bad weather, so the study of the structure alone it often gave mixed and unconvincing results.
Bobrovskiy and his colleagues, on the other hand, extracted and analyzed molecules from the inside, finding irrefutable remains of cholesterol, which made them lean towards animal nature. The oldest animal in the world.
The research is published in Science.
Roberta de carolis
Foto: Austrialian National University
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