Chinese scientists: conserved cells!
In contrast to the Franceville biota, scientists now found 167 specimens of 1.56-billion-year-old fossils with conserved cells! They belong to the next biota, the Montana biota. Shixing Zhu, Maoyan Zhu, Andrew H. Knoll, Zongjun Yin, Fangchen Zhao, Shufen Sun, Yuangao Qu, Min Shi & Huan Liu published their discovery on 17 May 2016 in Nature Communications (Nature Commun. 7: 11500; doi: 10.1038/ncomms11500).
They wrote: „Fossils of macroscopic eukaryotes are rarely older than the Ediacaran Period (635–541 million years), and their interpretation remains controversial. Here, we report the discovery of macroscopic fossils from the 1,560-Myr-old Gaoyuzhuang Formation, Yanshan area, North China, that exhibit both large size and regular morphology. Preserved as carbonaceous compressions, the Gaoyuzhuang fossils have statistically regular linear to lanceolate shapes up to 30 cm long and nearly 8cm wide, suggesting that the Gaoyuzhuang fossils record benthic multicellular eukaryotes of unprecedentedly large size. Syngenetic fragments showing closely packed ~10?µm cells arranged in a thick sheet further reinforce the interpretation. Comparisons with living thalloid organisms suggest that these organisms were photosynthetic, although their phylogenetic placement within the Eukarya remains uncertain.“
And they continued: „The new fossils provide the strongest evidence yet that multicellular eukaryotes with decimetric dimensions and a regular developmental program populated the marine biosphere at least a billion years before the Cambrian Explosion.“
It could be expected that there would be some disagreement. It was the „Guardian“ (18 May 2016) who summarized the pros and cons of this sensational discovery. Phil Donoghue, a professor of palaeobiology at the University of Bristol, described the discovery as a “big deal”. “They are not the oldest eukaryotes, but they are certainly the oldest demonstrably multicellular eukaryotes,” he said.
The „Guardian“: „But other experts were more sceptical. ‘There is nothing here to suggest that the specimens are eukaryotic, as opposed to bacterial,’ said Jonathan Antcliffe, a senior researcher in the University of Oxford’s department of zoology. Bacteria are, by definition, unicellular, and do not have distinct nuclei containing genetic material. Antcliffe suggested the fossils were more likely corresponded to colonies of bacterial cells, rather than a single complex organism. Truly multicellular creatures display three-dimensional form in which only some cells are in direct contact with the environment. This was ‘critically important for function be-cause it introduces transport problems for oxygen, nutrients and signalling molecules’ needed by the internal cells, Andrew Knoll of Harvard University explained in an article reviewing scientific literature on the origins of complex life.“
Even Abderrazak El Albani has doubts. He said, the level of detail in the study was “absolutely insufficient to tell us if these organisms were multicellular, eukaryotes or complex”. But to give proof of conserved cells in such old fossils would help to verify his own discovery from Gabon.
Maoyan Zhu is convinced of „his“ multicellular organisms. In a letter (19 December 2016) he wrote to me, comparing the fossils of Gabon and China: „In the community, very few believe these structures are individual organisms. In contrast, our Gaoyuzhuang fossils preserved as carbonaceous imprints exhibit regular morphology as shown by morphometric data.“ Howsoever: Things are in a state of flux. No boring billion, indeed. The old textbooks must be redesigned urgently. Prof Maoyan Zhu agrees: „I would say the 'boring billion’ is not that boring, more new discoveries and information are waiting for us. It is necessary to rewrite the textbook about early evolution of eukaryotes."