{"id":448786,"date":"2026-05-14T16:56:11","date_gmt":"2026-05-14T16:56:11","guid":{"rendered":"https:\/\/www.newsbeep.com\/ie\/448786\/"},"modified":"2026-05-14T16:56:11","modified_gmt":"2026-05-14T16:56:11","slug":"540-million-year-old-fossils-reveal-a-huge-surprise-about-early-life-on-earth","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/ie\/448786\/","title":{"rendered":"540-Million-Year-Old Fossils Reveal a Huge Surprise About Early Life on Earth"},"content":{"rendered":"

\"Intertwined<\/a>Visible to the naked eye, fossilized bacteria or algae were found in an ancient seabed that emerged in the current Brazilian state of Mato Grosso do Sul. Credit: Bruno Becker-Kerber\/Harvard University<\/p>\n

Scientists discovered that some of Earth\u2019s supposed earliest animal fossils were actually giant ancient microbes.<\/p>\n

Ancient microfossils discovered in Brazil are changing scientists\u2019 understanding of early life on Earth. Structures once believed to be traces left behind by tiny marine animals have now been identified as fossilized communities of microscopic bacteria and algae instead.<\/p>\n

The discovery suggests that during the Ediacaran period, around 540 million years ago, Earth\u2019s oceans may not yet have contained enough oxygen to support certain small invertebrates previously thought to exist at that time. The findings were published in the journal Gondwana Research.<\/p>\n

\u201cUsing microtomography and spectroscopy techniques, we observed that the microfossils have cellular structures \u2013 sometimes with preserved organic material \u2013 consistent with bacteria or algae that existed during that period. These aren\u2019t traces of animals that may have passed through the area,\u201d says Bruno Becker-Kerber, lead author of the study.<\/p>\n

Becker-Kerber conducted the work during his postdoctoral research at the Institute of Geosciences at the University of S\u00e3o Paulo (USP) and at the Brazilian Center for Research in Energy and Materials (CNPEM), supported by a FAPESP fellowship. He is currently continuing postdoctoral research at Harvard University in the United States.<\/p>\n

Ancient Fossils Challenge Early Animal Evidence<\/p>\n

Researchers had previously interpreted the fossil marks as signs of wormlike organisms or other tiny seafloor animals. If true, the fossils would have represented some of the oldest known examples of meiofauna, tiny invertebrates measuring less than one millimeter long.<\/p>\n

According to Becker-Kerber, the new findings point in a very different direction.<\/p>\n

The Ediacaran period came just before the Cambrian explosion, a major stage in Earth\u2019s history when rising oxygen levels helped fuel the rapid diversification of complex animals. Meiofauna are well documented in Cambrian fossils, but the new study suggests they may not have existed in these older environments after all.<\/p>\n

The research is part of the \u201cRio de la Plata Craton and Western Gondwana\u201d project, coordinated by Miguel Angelo Stipp Basei of IGc-USP and funded by FAPESP. Lucas Warren of S\u00e3o Paulo State University (IGCE-UNESP) in Rio Claro also contributed to the study with support from FAPESP.<\/p>\n

The fossils reexamined in the study came from Corumb\u00e1, while additional specimens were collected from rock outcrops in Bonito in the Serra da Bodoquena region. Both locations are in Mato Grosso do Sul within the Tamengo geological formation.<\/p>\n

Scientists say the rocks formed in a shallow marine environment along a continental shelf during the final stages of the supercontinent Gondwana\u2019s formation, before it later separated into landmasses that became South America and Africa.<\/p>\n

In a separate study, the same research group identified what may be the oldest known lichen fossil, also discovered in Mato Grosso do Sul and younger than the bacteria and algae described in this research.<\/p>\n

Advanced Tomography Revealed Hidden Cellular Structures<\/p>\n

To study the fossils in detail, researchers used the MOGNO beamline at Sirius, CNPEM\u2019s particle accelerator facility in Campinas. The equipment allowed scientists to examine fossils ranging from only a few micrometers to several millimeters in size.<\/p>\n

The samples underwent both microtomography and nanotomography, producing images at scales as small as micrometers (one-thousandth of a millimeter) and nanometers (one-billionth of a meter).<\/p>\n

\u201cWhen you have a large sample and want to image a structure inside it, the resolution obtained is often insufficient. The MOGNO beamline is one of the few in the world that performs so-called zoom tomography, in which we focus on something inside the sample and analyze it at the nanoscale without destroying the sample,\u201d says Becker-Kerber.<\/p>\n

He noted that earlier research interpreting the structures as animal traces did not have access to this imaging technology.<\/p>\n

Researchers also used Raman spectroscopy to analyze the fossils\u2019 chemical composition. The method revealed organic compounds in fossil cell walls, strengthening the idea that the structures are preserved microbial remains rather than trails left behind by animals moving through sediment.<\/p>\n

Giant Ancient Microbes in Prehistoric Seas<\/p>\n

Some specimens also contained pyrite, a mineral composed of iron and sulfur. Based on the fossils\u2019 shape and composition, scientists believe some may represent sulfur-oxidizing bacteria, organisms that rely on sulfur as part of their metabolism.<\/p>\n

\u201cThis group of bacteria is surprising. Some of the largest ever recorded belong precisely to this category. Unlike the common image we have of microscopic bacteria, certain species can reach diameters larger than a strand of hair and are visible to the naked eye,\u201d says Becker-Kerber.<\/p>\n

Although the fossils do not preserve features detailed enough for exact species identification, researchers observed preserved cells, divisions in cell walls, and traces of organic material at multiple collection sites. Scientists say these characteristics would not be expected if the structures were merely marks left behind by passing animals.<\/p>\n

The fossils also fall into three different size groups, suggesting several species may have existed together in microbial communities. The larger forms resemble green or red algae, while the smaller ones may include algae, cyanobacteria, or sulfur-oxidizing bacteria.<\/p>\n

\u201cThere are concave and convex partitions, coiled filaments, cells without sediment but containing organic matter. This evidence is much closer to bacteria or algae than to mere marks of disturbance caused by animals,\u201d the researcher concludes.<\/p>\n

The findings offer scientists a clearer picture of Earth\u2019s environment before the Cambrian explosion and may help researchers better understand the conditions that eventually allowed complex animal life to flourish.<\/p>\n

Reference: \u201cProposed Ediacaran meiofaunal burrows from Brazil are pyritized algal\/microbial consortia\u201d by Bruno Becker-Kerber, Nathaly Lopes Archilha, Andrew Knoll, Miguel Angelo Stipp Basei, Lucas Verissimo Warren, Lucas Del Mouro, Gilmar Kerber, Sharif Ahmed and Javier Ortega-Hern\u00e1ndez, 11 February 2026, Gondwana Research.
DOI: 10.1016\/j.gr.2026.01.011<\/a><\/p>\n

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