Decimetre-scale multicellular fossils from the 1.56-billion-year-old rocks of North China (Picture by ZHU Maoyan)
New fossils discovered in Northern China suggest that life "went large" on Earth more than 1.5 billion years ago, or nearly one billion years earlier than previously thought. This research has been published in Nature Communications DOI: 10.1038/ncomms11500, on May 18, 2016.
According to the report by Prof. ZHU Maoyan from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and his colleagues, these 1.56-billion-year-old, macroscopic multicellular eukaryotes fossils are preserved as carbonaceous (carbon-rich) compressions with size up to 30 cm long and 8 cm wide, which are discovered in the mudstone of the Mesoproterozoic "Gaoyuzhuang Formation" in the Yanshan region, Hebei Province. Among the total 167 measurable fossils, 53 fossils exhibit at least four regular shapes (linear, cuneate, oblong and tongue-shaped). Organic fragments extracted by acid maceration from the host rocks of the macroscopic Gaoyuzhuang fossils show extraordinarily well-preserved multicellular cell structure. Based on the morphometric analyses of these macrofossils and syngenetic cellular microfossils, authors interpret these Gaoyuzhuang fossils as benthic, multicellular and likely photosynthetic eukaryotes with unprecedentedly large size and a modest diversity populated in early Mesoproterozoic seas. However, their exact affinity remains uncertain. Further research will help to shed light into these ancient marine ecosystems.
Before discovery of the Gaoyuzhuang macrofossils, eukaryotes with comparable size do not know in the fossil record until ca. 600 million years ago in Ediacaran seas, so this new discovery predates diversification of macroscopic multicellular eukaryotes by nearly 1,000 million years. The Gaoyuzhuang macrofossils represent the compelling evidence for the early evolution of organisms large enough to be visible with the naked eye, and totally renew the current knowledge on early history of life written in textbook that the oldest known macroscopic organism is Grypania, a coiled and ribbon-like fossil of less two millimeters wide and few centimeters long during the early Proterozoic. Therefore, the discovery provides a crucial benchmark for our understanding of early evolution of eukaryotes, and stimulate new thinking on the Proterozoic Earth-life system which has been called as the "Boring Billion" or "Earth’s middle age" exhibiting evolutionary stasis.
The research project was supported by the National Natural Science Foundation of China, the Ministry of Science and Technology of China, the China Geological Survey, and the NASA Astrobiology Institute.
Prof. ZHU Maoyan
State Key Laboratory of Palaeobiology and Stratigraphy (LPS)
Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences
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Washington Post: Did you know Earth had a boring phase? Neither did these huge fossils
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