New Study Investigates 500-Million-Year-Old Fossils, Complex Life On Earth Began Earlier Than Once Thought

A new study has just been published investigating fossils that are over 500-million-years-old from the western region of Brazil and date back to the Ediacaran Period. The Ediacaran Period ranges from 635 to 542 million years ago, and the fossils studied have been found to be between 555-542 million years of age, edging very close to the Cambrian explosion of the next era.

These Brazilian fossils, which are half a billion years of age, are known as trace fossils. A trace fossil is comprised of the burrows and trace marks, which have been left behind by once living and thriving organisms. The 500-million-year-old fossils were a big surprise to paleontologists, who may now need to rethink previous theories and studies about the arrival of complex life on Earth.

To show just how ancient these fossils really are, just consider that dinosaurs were once walking the Earth in the Mesozoic Era, which was only 230 to 65 million years ago. While this may seem like an incredibly long time ago, it is still much more recent than the 500-million-year-old trace fossils in terms of Earth’s history.

The University of Manchester’s Russell Garwood was astonished at the age of the fossils that were studied, as ScienceAlert reported.

“This is an especially exciting find due to the age of the rocks. These fossils are found in rock layers which actually pre-date the oldest fossils of complex animals – at least that is what all current fossil records would suggest.”

A new study has just been published on the history of 500-million-year-old fossils originally found in sediment in Brazil.

Garwood went on to discuss the astounding events which took place in the pre-Cambrian and Cambrian era of Earth’s history.

“The evolutionary events during the Ediacaran-Cambrian transition are unparalleled in Earth history. That’s because current fossil records suggests that many animal groups alive today appeared in a really short time interval.”

The University of Bristol’s Luke Parry notes that the 500-million-year-old fossils prove that complex life existed in the Ediacaran Era, but due to their diminutive size, many of these were simply not noticed previously.

“Our new fossils show that complex animals with muscle control were around approximately 550 million years ago, and they may have been overlooked previously because they are so tiny.”

The 500-million-year-old fossils were approximately 50 to 600 micrometers in length, which means that they would have had a width equal to that of a human hair. In order to locate the fossils, scientists used a method known as X-ray microtomography, which is able to effectively scan the inside of objects like these fossils in 3D. This is crucial because if the fossils had to be opened up to conduct studies, it could have easily destroyed them.

The closest organism that scientists could think of when comparing the fossils to living creatures today is the roundworm. These once-living creatures would have been some of Earth’s first organisms that were able to control their movement on purpose as they burrowed and slid through the dirt.

The 500-million-year-old fossils found in Brazil are most easily compared with the roundworm of today.

According to Luke Parry, the fossils will help to greatly expand scientific knowledge of life during the Ediacaran Period. It is hoped that more fossils will be discovered from this time period so that scientists will be able to explore further.

“Our discovery highlights an unexplored window for tracking animal evolution in deep time.”

The latest study on the 500-million-year-old Brazilian fossils has been published in the journal, Nature Ecology & Evolution.

[Featured Image by Dan Kitwood/Getty Images]