Fat From Ancient Fossil Reveals Earliest-Known Animal

The discovery of fat molecules in a fossil 558 million years old confirms it as the oldest-known animal on record, a group of researchers announced on Friday.



The fossil is of a "strange creature called Dickinsonia, which grew up to 1.4 metres [4.6 feet] in length and was oval shaped with rib-like segments running along its body," said researchers from Australian National University (ANU) and elsewhere on the university's website.



The fossil -- discovered in a remote area near the White Sea in northwestern Russia -- belongs to the Ediacaran era, making it the earliest-known animal fossil in the world, according to the research team.



"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," Associate Professor Jochen Brocks from ANU was "ed as saying.



Molecules of cholesterol fat are produced only by animals, so their presence prove the fossil was an animal and not a fungus, single-celled protozoa, or plant, said the scientists.



"The fossil fat now confirms Dickinsonia as the earliest-known animal fossil, solving a decades-old mystery," Brocks said, adding that scientists had been fighting for decades over what Dickinsonia and other fossils of the Ediacaran era were.



The world of large animals emerged 540 million years ago during the Cambrian explosion, a period of unprecedented diversity in animal phyla.



To date, the earliest animal fossils in the records belonged to this period.



The research was published in Science Magazine, a journal of the American Association for the Advancement of Science. -