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Francevillian biota (Gabon)
2.1 billion years old (found 2010; debated)· Fossil or site· Microbes & cells
DebatedScientists disagree about when, how or why.
Centimeter-sized fossil-like shapes in 2.1-billion-year-old shales from Gabon, claimed as the oldest large multicellular organisms.
See it on the Life map →What happened
In 2010 a team led by Abderrazak El Albani described hundreds of flat, lobed structures, up to about 12 cm across, in black shales near Franceville, Gabon. The rocks are about 2.1 billion years old, laid down while oxygen was unusually high after the Great Oxidation Event. The team argued these were colonial, many-celled organisms; in 2019 they also reported string-like trails that might record movement. If real, the lineage left no known descendants.
Why it matters
If they are organisms, large multicellular life appeared about 1.5 billion years before animals, then vanished when oxygen fell again.
The evidence (fossils, genes, rocks)
Hundreds of specimens studied by CT scanning, plus carbon and sulfur isotopes suggesting a biological origin. Published in Nature in 2010, with follow-up studies in 2014 and 2019.
Still debated
Many scientists think the shapes could be mineral growths or microbial mats rather than true multicellular organisms. There is no consensus yet.
Connections (2)
▸Francevillian biota (Gabon) followed the oxygen rise of Great Oxidation EventDebated
The connection
The Francevillian fossils formed about 2.1 billion years ago, near the end of the Great Oxidation Event, when a spike in oxygen left shallow seas unusually well oxygenated. Their discoverers argue the extra oxygen let many-celled organisms try bigger bodies, which vanished when oxygen later declined.
When and how
Franceville Basin, Gabon, about 2.1 billion years ago; described by Abderrazak El Albani and colleagues in 2010.
How sure are we?
Rock chemistry in the same shales indicates oxygenated bottom water, and the timing matches a global carbon isotope spike (the Lomagundi event) linked to high oxygen.
Debates and open questions
Whether the fossils are organisms at all, and whether the oxygen spike caused them or merely coincided with them, remain disputed.
▸Francevillian biota (Gabon) may be an early attempt at Multicellular lifeDebated
The connection
If the Francevillian structures were living organisms, they would be colonial or multicellular life about 2.1 billion years ago, roughly half a billion years before other good evidence. They would represent an early experiment that died out, not ancestors of later plants or animals.
When and how
Franceville Basin, Gabon, about 2.1 billion years ago; El Albani's team described them in 2010 and reported possible movement trails in 2019.
How sure are we?
Shapes, sizes and isotope signals suggest biology, but they could also be mineral or microbial-mat structures.
Debates and open questions
No cell structure is preserved, so whether they were complex cells, bacterial colonies or non-living features remains unresolved.