The microscopic beings left string-shaped impressions in 2.1 billion-year-old rock, meaning lifeforms appear to have been capable of independent movement 1.5 billion years earlier than once thought, according to a recent study.
The fossils seem to retrace the path of the creatures as they searched for food, moving toward a multi-layered mat of microorganisms on the muddy seabed, according to Dr. Luis Buatois, a geological sciences professor at USask.
The impressions in the rock were strikingly similar to indentations found in younger fossils that indicate life capable of movement, referred to as “motility.”
Buatois said it’s rare to “find things that actually challenge what we know as it is stated in the textbooks.”
“Sometimes you find things that can do minor adjustments, but this is actually a big, big change because we are tracing motility back in time for a long, long time,” Buatois said.
Buatois and USask professor Dr. Gabriela Mángano, went to France in 2014 to study fossils found in the African country of Gabon.
Working with a team of international scientists, they conducted CT scans to create 3D images and analyzed roughly 80 different specimens.
“We don’t think they are animals. They are too old for that,” Buatois said.
The most basic, true animals emerged more than 550 million years ago during a period known as the Cambrian Explosion, Buatois said.
Right before then, there was a rapid rise in oxygen levels in the ocean, he said. Similarly, researchers suspect there was a dramatic increase in oxygen that led to the slug-like organisms in Gabon.
The group’s findings are outlined in a paper published last week in the academic journal Proceedings of the National Academy of Sciences of the United States of America.