CANBERRA, June 8 (Xinhua) -- Australian scientists have discovered a "lost world" of ancient organisms that lived in Earth's waterways billions of years ago.
In a study published on Thursday, a team from Australian National University (ANU) revealed the discovery of the Protosterol Biota, a microscopic creature that could have been the first predator on Earth, hunting and devouring bacteria.
A member of the eukaryotes family of organisms, the Protosterol Biota was abundant in marine ecosystems around the world and likely played a key role in shaping ecosystems.
Modern forms of eukaryotes include fungi, plants, animals and single-celled organisms. It is thought that all nucleated creatures trace back to the Last Eukaryotic Common Ancestor (LECA), which lived more than 1.2 billion years ago.
Benjamin Nettersheim and Jochen Brocks from ANU discovered molecular remains of the Protosterol Biota in 1.6 billion-year-old rocks recovered from Australia's Northern Territory (NT).
"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?" Nettersheim said.
"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."
The creature is thought to have thrived on Earth from 1.6 billion years ago to approximately 800 million years ago, coinciding with the emergence of more complex organisms. ■