Stunning fossil discovery challenges the origins of animal life
Key takeaways
- Scientists studying ancient microfossils from Brazil have discovered that structures once believed to be traces left behind by tiny animals were actually formed by communities of microscopic bacteria and algae.
- The research focused on fossils found in the Brazilian state of Mato Grosso do Sul and was published in the journal Gondwana Research.
- These aren't traces of animals that may have passed through the area," says Bruno Becker-Kerber, the first author of the study.
Why this matters: new research or scientific developments with potential real-world impact.
Scientists studying ancient microfossils from Brazil have discovered that structures once believed to be traces left behind by tiny animals were actually formed by communities of microscopic bacteria and algae. The findings challenge previous ideas about when small animals first appeared on Earth and suggest oxygen levels in ancient oceans may still have been too low to support certain forms of animal life around 540 million years ago.
The research focused on fossils found in the Brazilian state of Mato Grosso do Sul and was published in the journal Gondwana Research. Earlier studies had interpreted the marks as evidence of wormlike creatures or other tiny marine animals moving through seafloor sediment during the Ediacaran period, which came just before the Cambrian explosion.
"Using microtomography and spectroscopy techniques, we observed that the microfossils have cellular structures -- sometimes with preserved organic material -- consistent with bacteria or algae that existed during that period. These aren't traces of animals that may have passed through the area," says Bruno Becker-Kerber, the first author of the study. He carried out the research during postdoctoral work at the Institute of Geosciences at the University of S o Paulo (USP) and at the Brazilian Center for Research in Energy and Materials (CNPEM), with support from FAPESP.