Scientists find ‘lost world’ in billion-year-old Australian rock

Scientists have discovered a “lost world” of ancient organisms in billion-year-old rocks from northern Australia that they say could change the world’s understanding of humans’ earliest ancestors.

The microscopic creatures, known as Protosterol Biota, are part of a family of organisms called eukaryotes and lived in Earth’s waterways about 1.6 billion years ago, according to the researchers.Eukaryotes have a complex cell structure that includes mitochondria, the cell’s “powerhouse”, and a nucleus, its “control and information centre”.

Modern forms of eukaryotes include fungi, plants, animals and single-celled organisms such as amoebae.

Humans and all other nucleated creatures can trace their ancestral lineage back to the last eukaryotic common ancestors (LECA), which lived more than 1.2 billion years ago.

The new discoveries “appear to be the oldest remnants of our own lineage – they lived even before LECA,” said Benjamin Nettersheim, who completed his PhD at the Australian National University (ANU) and is now based at the University of Bremen in Germany.

“These ancient creatures were abundant in marine ecosystems across the world and probably shaped ecosystems for much of Earth’s history.”

The discovery of the Protosterol Biota is the result of 10 years of work by researchers from ANU and was published in Nature on Thursday.

ANU’s Jochen Brocks, who made the discovery with Nettersheim, said the Protosterol Biota were more complex than bacteria and presumably larger, although it is unknown what they looked like.

“We believe they may have been the first predators on Earth, hunting and devouring bacteria,” the professor said in a statement.