AsianScientist (May 25, 2016) – 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 was published in Nature Communications.
Before the discovery of the Gaoyuzhuang macrofossils, eukaryotes with comparable sizes—at least large enough to be visible with the naked eye—were absent from fossil records until ca. 600 million years ago, in Ediacaran seas.
According to the report by Professor Zhu Maoyan from Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences and colleagues, these 1.56-billion-year-old, macroscopic multicellular eukaryote fossils are preserved as carbonaceous (carbon-rich) compressions with sizes up to 30 cm long and 8 cm wide. They were discovered in the mudstone of the Mesoproterozoic Gaoyuzhuang Formation in the Yanshan region of 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, researchers interpret the Gaoyuzhuang fossils as benthic, multicellular and likely photosynthetic eukaryotes with unprecedentedly large sizes 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.
Today’s textbooks teach that the oldest known macroscopic organism is Grypania, a coiled and ribbon-like fossil of less than two millimeters wide and few centimeters long during the early Proterozoic. The Gaoyuzhuang macrofossils rewrite current knowledge of the early history of life; therefore, the discovery provides a crucial benchmark for our understanding of the early evolution of eukaryotes.
The article can be found at: Zhu et al. (2016) Decimetre-Scale Multicellular Eukaryotes from the 1.56-Billion-Year-Old Gaoyuzhuang Formation in North China.
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Source: Chinese Academy of Sciences.
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