Fossil Friday: Update on the Dubious Nature of the Precambrian Gabonionta
In a Fossil Friday article last year (Bechly 2023) I discussed the dubious status of an assemblage of alleged Precambrian macrofossils from West Africa that have been informally called Gabonionta. Meanwhile, two new articles on the subject have been published, so that I here present an updated and expanded version of my article.
“According to conventional thinking, unequivocal evidence for eukaryotic fossils first appeared in the geological record some 1700–1600 million years ago” (Chi Fru et al. 2024). However, in 2008 the Moroccan-French geologist Prof. Abderrazak El Albani from the University Poitiers discovered strange three-dimensionally preserved radial structures in Proterozoic rocks of the Francevillian Formation in the West African country Gabon, which are believed to be about 2.1 billion years old. The ear-shaped structures of up to 6.7 inch size were interpreted as earliest fossil evidence for oxygen-respiring, multicellular eukaryotic life forms and were published two years later in the prestigious journal Nature (El Albani et al. 2010, Maxmen 2010).
Somewhat More Cautious
This original description was somewhat more cautious than the later public presentation of the discovery. The authors said:
We consider it most likely that these structures represent fossilized colonial organisms … it is also possible that they represent colonial eukaryotes. … Although we cannot determine the precise nature and affinities of the 2.1-Gyr macroorganisms from the Francevillian B Formation of Gabon, we interpret these fossils as ancient representatives of multicellular life, which expanded so rapidly 1.5 Gyr later.
In 2014, these findings were first presented to the general public with a special exhibition titled “Experiment Life: The Gabonionta” opened in March 2014 at the Natural History Museum in Vienna (), which also featured a 40-minute documentary film by the University of Poitiers about the discovery. This exhibition was accompanied by a sensationalist media campaign, which included fancy headlines such as: “Gabonionta: sensational discovery in Vienna” (ORF 2014), “Gabonionta, the little revolutionaries of evolution” (Vosatka 2014), or “Gabonionta: How multicellular organism tried to conquer the Earth” (Anonymous 2014).
Remarkable and Highly Unusual
It is remarkable and highly unusual in bioscience that the new taxon Gabonionta was never formally described as scientific name, but only used informally in public presentations and press releases. While El Albani refrained from formally naming the fossils, the new name Gabonionta was first introduced by the head of the paleontology department, Dr. Matthias Harzhauser, on occasion of the mentioned special exhibition at the Natural History Museum of Vienna. Therefore, it is commonly thought that this name Gabonionta, which designates a supposed independent and extinct branch of multicellular life, is not taxonomically valid because it was not properly described according to the international rules of nomenclature. However, this is not true, because these rules do not apply to higher taxa above the family group level. Even if this name was only used in popular science publications, it is as scientifically valid and available just as other higher taxonomic names such as Eukaryota or Metazoa.
Anyway, there are more important issues with this discovery: other experts such as the late great German paleontologist Prof. Adolf Seilacher remained highly sceptical about the interpretation and suggested that the structures rather represent only pseudo-fossils formed by abiotic pyrite crystals during the diagenesis of the rocks. El Albani et al. (2014) responded to this critique and objected that not all of the fossils are pyritized and that the fossils formed at the same time as the sediment and therefore could not have been produced later by metamorphic processes. However, the initial critique was later strongly corroborated by the discovery of very similar structures from 1.1 billion year old sediments of Lake Michigan that were described by the authors as inorganic concretions (Anderson et al. 2016). Therefore, Javaux & Lepot (2018) remarked that “the identity of these macrostructures remains unknown and their biogenicity is questionable”.
Just a year later, El Albani et al. (2019) defended the organic origin and syngenicity of some other alleged fossils from the Francevillian Formation, and boldly suggested that they were analog to “the aggregation of amoeboid cells into a migratory slug phase in cellular slime molds.” This cannot be so easily dismissed, as this publication includes among its co-authors some world renowned experts such as Drs. Stefan Bengtson, Luis Buatois, and Gabriela Mangano. Nevertheless, other experts remained very much unconvinced. More recently, Fakhraee et al. (2023) again came to the devastating finding that these structures could rather represent abiotic concretions and synaeresis cracks. They concluded that “in light of their stratigraphic age, unusual morphology, and the relative rarity of these features, a eukaryote affinity for these features—or affinity with analogously complex multicellular organisms — remains uncertain.” It looks like the dubious name Gabonionta may not even refer to any organism that ever existed. The scientists simply made up a new domain of life, based on nothing but inorganic patterns in ancient rocks.
Nothing But Hype?
Is there any other evidence that this sensational discovery was nothing but hype? Sure there is: after the 2014 media circus nobody ever published any primary research again about these “fossils” and the mysterious Gabonionta, at least until last year (see below). Even in their newer papers about the Francevillian Biota, El Albani and his colleagues only described lenticular structures produced by agglutinated protists (Lekele Baghekema et al. 2017, Reynaud et al. 2017, El Albani et al. 2019, 2023), but no longer promoted the presence of truly multicellular organisms. The silence was deafening!
Even, the mentioned two most recent works on the assumed Francevillian fossils, which appeared after my first article on this subject, again only defended their biogenic origin and eukaryotic nature. Ossa Ossa et al. (2023) did not base their conclusions on a study of the fossil structures but on geochemical evidence from Zinc enrichment, which could be consistent with eukaryotic metabolism. However, they openly admitted that “geochemical evidence presented here also cannot resolve the exact type of eukaryotic organisms that inhabited the Francevillian basin, i.e., colonies of multiple cells or individual, large complex multicellular organisms.” Moreover, there is no independent confirmation yet that the enrichment of Zinc isotopes could not be alternatively better explained with inorganic processes or prokaryotic microbial activity. After all, these structures are pyritized, which is quite typical for bacterial metabolic activity during fossilization (Janssen et al. 2022). Ossa Ossa et al. devote a whole lengthy chapter of their discussion to the question if the Zinc enrichment is based on prokaryotic or eukaryotic metabolic processes, but in the last paragraph they have to admit that:
However, it is important to emphasize here that studies of Zn isotope fractionation by eukaryotes have been focused exclusively on modern photosynthetic eukaryotes. This leaves the uncertainty whether strong enrichment in light Zn isotopes represents a distinct trait of the whole eukaryotic domain and whether the Francevillian Group fossilized structures represent photosynthetic or non-photosynthetic eukaryotes.
Indeed, Ossa Ossa et al. are careful to conclude that their data only “may [my emphasis] point to their eukaryotic rather than prokaryotic affinity” and “once confirmed [my emphasis], this would provide a critical calibration point for eukaryogenesis.”
The Usual Evolutionist Word Salad
The newest study by Chi Fru et al. (2024), which has Dr. El Albani as senior author, did not look at the alleged fossils either, but instead found a correlation of the Francevillian Formation with a “previously unrecognized local pulse in dissolved seawater P concentration, of comparable magnitude to Ediacaran seawater levels”, which seems to have been caused by “an episode of intense submarine hydrothermal alteration of a nutrient-rich seafloor reservoir”. The authors interpret this slim data point as evidence that “hydrothermal seawater eutrophication triggered local macrobiological experimentation in the 2100 Ma Paleoproterozoic Francevillian sub-basin” and “nutrient enrichment initiated localized emergence of large colonial macrofossils in the Franceville sub-basin.” In spite of these weak speculations based on highly circumstantial evidence, the new study was sold to the public in a press release titled “complex life on Earth began around 1.5 billion years earlier than previously thought” (Cardiff University 2024). If you read the original study you will find the usual evolutionist word salad of “may have”, “could have”, “likely have”, “possibly reflects”, and “might explain”. Not exactly the usual vocabulary of hard science.
Here is what I tentatively suggest is more likely what really happened: a surplus of nutrients (such as phosphates) triggered a lot of microbial activity that resulted in different concentrations of elements and the formation of pseudo-fossils. Maybe some of the protists already were eukaryotic and maybe some of them formed colonial aggregations, or maybe not, we have no clue. What we definitely do not find here is any credible evidence for an evolutionary transition to genuine multicellular eukaryotes, as was initially claimed with the overhyped discovery of the Gabonionta.
References
Anderson RP, Tarhan LG, Cummings KE, Planavsky NJ, Bjørnerud M 2016. Macroscopic structures in the 1.1 Ga continental Copper Harbor Formation: Concretions of fossils? Palaios 31(7), 327–338. DOI: https://doi.org/10.2110/palo.2016.013
Anonymous 2014. Gabonionta: Wie Mehrzeller versuchten, die Erde zu erobern. OÖNachrichten March 8, 2014. https://www.nachrichten.at/panorama/weltspiegel/Gabonionta-Wie-Mehrzeller-versuchten-die-Erde-zu-erobern;art17,1323424
Bechly G 2023. Fossil Friday: How an Austrian Scientist Concocted a New Domain of Life called Gabonionta. Evolution News June 2, 2023. https://evolutionnews.org/2023/06/fossil-friday-how-an-austrian-scientist-concocted-a-new-domain-of-life-called-gabonionta/
Cardiff University 2024. Complex life on Earth began around 1.5 billion years earlier than previously thought, new study claims. Phys.org July 29, 2024. https://phys.org/news/2024-07-complex-life-earth-began-billion.html
Chi Fru E, Aubineau J, Bankole O, Ghnahalla M, Soh Tamehe L & El Albani A 2024. Hydrothermal seawater eutrophication triggered local macrobiological experimentation in the 2100 Ma Paleoproterozoic Francevillian sub-basin. Precambrian Research 409: 107453, 1–17. DOI: https://doi.org/10.1016/j.precamres.2024.107453
El Albani A, Bengtson S, Canfield DE et al. 2010. Large colonial organisms with coordinated growth in oxygenated environments 2.1 Gyr ago. Nature 466(7302), 100–104. DOI: https://doi.org/10.1038/nature09166El Albani A, Bengtson S, Canfield DE et al. 2014. The 2.1 Ga Old Francevillian Biota: Biogenicity, Taphonomy and Biodiversity. PLoS ONE 9(6):e99438, 1–18. DOI: https://doi.org/10.1371/journal.pone.0099438
El Albani A, Mangano MG, Buatois LA, Bengtson S, Riboulleau A, Bekker A, Konhauser K, Lyons T, Rollion-Bard C, Bankole O, Lekele Baghekema SG, Meunier A, Trentesaux A, Mazurier A, Aubineau J, Laforest C, Fontaine C, Recourt P, Chi Fru E, Macchiarelli R, Reynaud JY, Gauthier-Lafaye F & Canfield DE 2019. Organism motility in an oxygenated shallow-marine environment 2.1 billion years ago. PNAS 116(9), 3431–3436. DOI: https://doi.org/10.1073/pnas.181572111
El Albani A, Konhauser KO, Somogyi A et al. 2023. A search for life in Palaeoproterozoic marine sediments using Zn isotopes and geochemistry. Earth and Planetary Science Letters 612:118169, 1–13. DOI: https://doi.org/10.1016/j.epsl.2023.118169
Fakhraee M, Tarhan LG, Reinhard CT, Crowe SA, Lyons TW & Planavsky NJ 2023. Earth’s surface oxygenation and the rise of eukaryotic life: Relationships to the Lomagundi positive carbon isotope excursion revisited. Earth-Science Reviews 240: 104398. DOI: https://doi.org/10.1016/j.earscirev.2023.104398
Janssen K, Mähler B, Rust J, Bierbaum G & McCoy VE 2022. The complex role of microbial metabolic activity in fossilization. Biological Reviews 97(2), 449–465. DOI: https://doi.org/10.1111/brv.12806
Javaux EJ & Lepot K 2018. The Paleoproterozoic fossil record: Implications for the evolution of the biosphere during Earth’s middle-age. Earth-Science Reviews 176, 68–86. DOI: https://doi.org/10.1016/j.earscirev.2017.10.001
Lekele Baghekema SG, Lepot K, Riboulleau A, Fadel A, Trentesaux A & El Albani A 2017. Nanoscale analysis of preservation of ca. 2.1 Ga old Francevillian microfossils, Gabon. Precambrian Research 301, 1–18. DOI: https://doi.org/10.1016/j.precamres.2017.0
Maxmen A 2010. Ancient macrofossils unearthed in West Africa. Nature News June 30, 2010. DOI: https://doi.org/10.1038/news.2010.323
NHM 2014. Experiment Life – the Gabonionta. Press release March 7, 2014. ORF 2014. „Gabonionta“: Sensationsfund in Wien. ORF.at March 11, 2014. https://wien.orf.at/v2/news/stories/2635417/
Ossa Ossa F, Pons M-L, Bekker A, Hofmann A, Poulton SW, Andersen MB, Agangi A, Gregory D, Reinke C, Steinhilber B, Marin-Carbonne J & Schoenberg R 2023. Zinc enrichment and isotopic fractionation in a marine habitat of the c. 2.1 Ga Francevillian Group: A signature of zinc utilization by eukaryotes? Earth and Planetary Science Letters 611: 118147, 1–13. DOI: https://doi.org/10.1016/j.epsl.2023.118147
Reynaud J-Y, Trentesaux A, El Albani A et al. 2017. Depositional setting of the 2·1 Ga Francevillian macrobiota (Gabon): Rapid mud settling in a shallow basin swept by high-density sand flows. Sedimentology 65(3), 670–701. DOI: https://doi.org/10.1111/sed.12398
Vosatka M 2014. Gabonionta, die kleinen Revolutionäre der Evolution. DerStandard March 11, 2014. https://www.derstandard.at/story/1392687847479/gabonionta-die-kleinen-revolutionaere-der-evolution
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