image: These are external volume transparencies at different heights in the sample. Oblique to vertical position of string-shaped structure is shown at the top-left side. view more
Credit: Abderrazak El Albani
Researchers report that some organisms were capable of movement approximately 1.5 billion years earlier than originally thought. The oldest trace fossils are approximately 635 million years old, and records show that organisms from that period could move on the surface of and within sediment. Using chemical analyses, 3D tomographic reconstructions, and scanning electron microscopy, Abderrazak El Albani, Donald Canfield, and colleagues examined string-shaped, 6-170 mm long pyritized structures preserved in shale from Gabon's Franceville basin. Chemical conditions, such as high levels of sulphate, within the basin allowed for the rapid pyritization of these structures, which were originally made of organic matter and were likely mucus strands left by organisms moving through mud. The size and complexity of the fossilized strands suggest that they were created by the movements of aggregated eukaryotes that formed multicellular organisms. The impetus for these organisms to become motile may have stemmed from a need to find food sources. The fossils dated back to 2.1 billion years ago, when Earth was oxygen rich and had ideal conditions for simple cellular life to become more complex. Although the Francevillian biota may represent a unique fossiliferous window, the findings suggest that complex biological processes, such as mobility and multicellularity, had evolved 300 million years earlier than the oldest documented eukaryotes and more than 1.5 billion years before the emergence of mobile animals, according to the authors.
Article #18-15721: "Organism motility in an oxygenated shallow-marine environment 2.1 billion years ago," by Abderrazak El Albani et al.
MEDIA CONTACT: Abderrazak El Albani, University of Poitiers, FRANCE; tel: +33-672852088; email: abder.albani@univ-poitiers.fr
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