Francevillian biota

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Gabonionta, earliest form of multicellular life

The Francevillian biota (also known as Gabon macrofossils or Gabonionta) is a group of 2.1-billion-old Palaeoproterozoic, macroscopic organisms known from fossils found in the west-African country of Gabon in the Palaeoproterozoic Francevillian B Formation, a black shale province. The fossils have since been regarded as the earliest form of multicellular life.[1] The fossils were discovered by an international team led by the Moroccan-French geologist Abderrazak El Albani, of the University of Poitiers, France. While the fossils have yet to be assigned to a formal taxonomic position, they have been informally and collectively referred to as the "Gabonionta" by the Natural History Museum Vienna in 2014.[2]

Morphology[edit]

A member of the Francevillian biota. Maximum fossil diameter= 12 cm

The fossil organisms are up to 12 cm in size.[3] 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.[3] Cell-cell communication must be assumed as it existed before multi-cellularity arose.[4]

Locality[edit]

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.[3]

Interpretations[edit]

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.[5]

See also[edit]

References[edit]

  1. ^ El Albani, Abderrazak; Bengtson, Stefan; Canfield, Donald E.; Riboulleau, Armelle; Rollion Bard, Claire; Macchiarelli, Roberto et al. (2014). "The 2.1 Ga Old Francevillian Biota: Biogenicity, Taphonomy and Biodiversity". PLoS ONE 9 (6): e99438. doi:10.1371/journal.pone.0099438. 
  2. ^ Experiment Life – the Gabonionta. (Press Release). 4 March 2014. Naturhistorisches Museum Wien
  3. ^ a b c El Albani, Abderrazak; Bengtson, Stefan; Canfield, Donald E.; Bekker, Andrey; Macchiarelli, Roberto; Mazurier, Arnaud; Hammarlund, Emma U.; et al. (2010). "Large colonial organisms with coordinated growth in oxygenated environments 2.1 Gyr ago". Nature 466 (7302): 100–104. Bibcode:2010Natur.466..100A. doi:10.1038/nature09166. PMID 20596019. 
  4. ^ Sebe-Pedros, A.; Roger, A. J.; Lang, F. B.; King, N.; Ruiz-Trillo, I. (2010). "Ancient origin of the integrin-mediated adhesion and signaling machinery". Proceedings of the National Academy of Sciences 107 (22): 10142–10147. Bibcode:2010PNAS..10710142S. doi:10.1073/pnas.1002257107. 
  5. ^ Maxmen, Amy (30 June 2010). "Ancient macrofossils unearthed in West Africa". Nature. doi:10.1038/news.2010.323. 
Preceded by Archean Eon Proterozoic Eon Followed by Phanerozoic Eon
Paleoproterozoic Era Mesoproterozoic Era Neoproterozoic Era
Siderian Rhyacian Orosirian Statherian Calymmian Ectasian Stenian Tonian Cryogenian Ediacaran