francevillian biota francevillian biota the francevillian biota (also referred to as gabon macrofossils, gabonionta or francevillian group fossils) are a collection of 2.1-billion-year-old palaeoproterozoic, macroscopic fossils of organisms known from the palaeoproterozoic francevillian b formation in gabon, a black shale province notable for its lack of any noticeable metamorphism. the fossils are postulated to be evidence of the earliest form of multicellular life, and of eukaryotes. they were discovered by an international team led by moroccan-french geologist abderrazak el albani, of the university of poitiers, france. while they have yet to be assigned to a formal taxonomic position, they have been informally and collectively referred to as the "gabonionta", including by the natural history museum vienna in 2014. francevillian biota artistic interpretation of the newly discovered planktonic organisms. scientific classification domain: eukaryota (unranked): francevillian biota part of a series onthe francevillian basin preservation biota history geology and localities francevillian b formation francevillian a formation oklo mine fossils francevillian biota (also see akouemma) evolutionary concepts great oxidation event shunga-francevillian event huronian glaciation lomagundi event origin of life further macroscopic fossils, discovered in 2023, were characterized as multicellular eukaryotes. morphology members of the francevillian biotafrancevillian biota fossil at display at the natural history museum, vienna.note the middle of the two fossils suggest either postmortem deformation or longitudinal fission, although it's unlikely to be both. the fossil organisms are up to 17 centimetres (6.7 in) in size. their bodies were flattened disks with a characteristic morphology, including circular and elongated individuals. a spherical to ellipsoidal central body is bounded by radial structures. the fossils show three-dimensionality and coordinated growth. cell-cell communication must be assumed as it existed before multi-cellularity arose. a newer 2014 study by el albani et al. describes multiple types of fossils with different morphologies. there are convoluted tubes, and "string of pearls"-like structures that terminate in a "flower". this is similar to dictyostelid slime molds, amoebal organisms that form multicellular assemblies to migrate. however, dictyostelids are terrestrial, not marine organisms so the structures cannot simply be dictyostelids. among known fossils, the ediacaran nemiana and beltanelloides are most similar when compared to the "string of pearls". in 2023, subsequent fossils were discovered, and characterized as eukaryotes. they appear to be flattened lenticular disks reaching up to 4.5 cm in diameter, with a chambered interior surrounded by a notched ridge about 1/6th of the diameter in width. the latter has been hypothesized to play a role in their movement through the water column, as the organisms were likely planktonic. they were found to have an unusual concentration of zinc compared to the surrounding sediments, an element performing key function in eukaryote biochemistry. locality geology of the francevillian basin the findings come from shales of the franceville basin with a high fossil density of up to 40 individuals per square meter. presumably, the organisms survived at the bottom in shallow sea water in colonies. the geochemistry of the fossil site indicates that they lived on the sediment under an oxygenated water column of a prograding delta, and they might have engaged in aerobic respiration. interpretations in describing the fossils, el albani and colleagues described them as colonial organisms with possible affinities to eukaryotes, akin to microbial mats, albeit unlike any known structures in the fossil record, yet noting the complexity of the fossils and presence of sterane as suggestive of possible eukaryote identity. in a concurrent news report in nature, paleontologist philip donoghue of bristol university advocates a more conservative approach pending further evidence before calling them eukaryotes. another view, held by yale's adolf seilacher, interprets the fossils as not organisms at all, but rather pseudofossils of inorganic pyrites. el albani et al. (2014) explicitly disputes seilacher's interpretation. both pyritized and unpyritized impressions of the structures remain, as well as lightly pyritized forms. the structures formed in a single event, at the same time as the sediment. this is demonstrated by the uniform distribution of sulfur isotope ratios within the sample. in pyrite flowers, which crystallize slowly, the isotope ratio would vary within the structure. for structures that resemble pollen, chemical analysis also shows that the material in the walls of the "pollen" contains organic material. fate the francevillian biota disappears and is absent in the overlying black shale. el albani attributes this to their extinction. the biota formed with the great oxidation event, a temporary increase in atmospheric oxygen, and became extinct from marine anoxia when the event was terminated by the drop in oxygen levels of the lomagundi event. the biota represents the earliest known experiment in multicellularity.