Paleontologists have analyzed a mysterious fossil species called Dickinsonia and realized that they were looking at the earliest animal ever known to live on Earth. They concluded in a study published this week in the journal Science that the animal lived 558 million years ago.
This fossil species has been long debated, some studies saying it was an ancient lichen or an amoeba of gigantic proportions, placing it in time several million years later.
“The Holy Grail of Palaeontology”
Scientists call the discovery of the fossil “the Holy Grail of palaeontology.” It was found by Ilya Bobrovskiy (Australian National University) near the White Sea from northwest Russia.
Dickinsonia is from the Ediacaran period, which is 20 million earlier than the Cambrian period, or the “Cambrian explosion” – a period when complex animals like mollusks or worms emerged.
The study shows that long before the Cambrian period, animals were already evolved, not just plants, fungi or unicellular bacteria.
Dickinsonia was not a small creature. The one discovered by Bobrovskiy was 1.4 meters long. Because of the fossilization process, the creature appeared almost oval. It left fine ridges on both sides of a center-line.
Scientists have known about this species for almost 75 years. However, many of these fossils were found in Australia, in Ediacara Hills, but were not preserved as good as this last fossil. Bobrovskiy was impressed to find the creature’s traces 100 meters above the White Sea, on a cliff. The fossil was in such a good state of preservation that it still had fat molecules. Analysis of these molecules showed a type of fat – cholesterol, which was only found in animals, thus making Dickinsonia an animal.
Co-author of the study, Jochen Brocks, stated:
“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. 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.”
Andre Blair s is the lead editor for Advocator.ca. He holds a B.A. in Psychology from the University of Toronto, and a Master of Science in Public Health (M.S.P.H.) from the School of Public Health, Department of Health Administration, at the University of North Carolina at Chapel Hill. Andre specializes in environmental health, but writes on a variety of issues.