Researchers from Australia have discovered a "lost world" of ancient creatures that previously lived in the Earth's waters 1.6 billion years ago. For the research community, the experts think that this finding might alter how we view our earliest ancestors.
According to a news release by The Australian National University (ANU), "Known as the 'Protosterol Biota', these microscopic creatures are part of a family of organisms called eukaryotes. Eukaryotes have a complex cell structure that includes mitochondria, known as the "powerhouse" of the cell, and a nucleus that acts as the "control and information centre". The Protosterol Biota are believed to be our earliest known ancestors."
This phenomenal discovery was made after ten years of hard work by the researchers, and the findings were published in the journal Nature. According to the researchers, these organisms could have been the first predators on Earth.
These ancient creatures were abundant in marine ecosystems across the world and probably shaped ecosystems for much of Earth's history. The researchers say the Protosterol Biota lived at least one billion years before any animal or plant emerged.
"Molecular remains of the Protosterol Biota detected in 1.6-billion-year-old rocks appear to be the oldest remnants of our own lineage - they lived even before LECA. These ancient creatures were abundant in marine ecosystems across the world and probably shaped ecosystems for much of Earth's history," Dr Benjamin Nettersheim, who completed his PhD at ANU and is now based at the University of Bremen in Germany, said.
"Modern forms of eukaryotes are so powerful and dominant today that researchers thought they should have conquered the ancient oceans on Earth more than a billion years ago.
"Scientists have long searched for fossilised evidence of these early eukaryotes, but their physical remains are extremely scarce. Earth's ancient oceans rather appeared to be largely a bacterial broth.
"One of the greatest puzzles of early evolution scientists have been trying to answer is: why didn't our highly capable eukaryotic ancestors come to dominate the world's ancient waterways? Where were they hiding?
"Our study flips this theory on its head. We show that the Protosterol Biota were hiding in plain sight and were in fact abundant in the world's ancient oceans and lakes all along. Scientists just didn't know how to look for them - until now."
Professor Jochen Brocks from ANU, who made the discovery with Dr Nettersheim, said the Protosterol Biota were certainly more complex than bacteria and presumably larger, although it's unknown what they looked like.
"We believe they may have been the first predators on Earth, hunting and devouring bacteria," Professor Brocks said.
