Scientists at the Australian National University have discovered the earliest known animal fossil dating back 558 million years.
The creature, known as Dickinsonia, was previously found in northwest Russia near the White Sea. It had not been classified before, until other recently found Dickinsonia fossils showed the presence of organic tissue, allowing researchers to identify molecules of cholesterol, described as "a hallmark" of animals. Its body measured approximately 5 feet in length and was oval shaped with rib-like segments running along its body. “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.
A biomarker is basically any substance that points to the presence of biological processes. Incredibly, after 558 million years, this fossil still contains traces of organic matter in the form of a lipid, namely cholesteroids. A “striking abundance” of cholesterol molecules, upwards of 93 percent of the organic material extracted, was detected within the specimen. Alex Liu, a paleontologist at the University of Cambridge who wasn’t involved in the new study, says the new paper is “remarkable” in that the scientists were able to recognize traces of original organic molecules in such an ancient fossil. Dickinsonia came from a period known as the Ediacaran. Dickinsonia was probably not the first animal on Earth but for the moment we don’t know any other.