North China unearths 1.63 billion-year-old multicellular fossils
Multicellularity is vital to the functional and ecological success of the Eukarya (a group of organisms including plants, animals, and fungi), and the evolution of multicellularity lies deep in history and process. Simple multicellular organisms among eukaryotes, like uniseriate filaments and coenobia, have recently been widespread. However, scientists have been unable to state when this innovation arose precisely.
The only known fact is that eukaryotes with simple multicellularity arose long before the advent of the complex multicellular animals as red and green algae and putative fungi appeared as early as 1.05 billion years ago. We rely primarily on paleontological records to give somewhat accurate information on when and under what conditions multicellular eukaryotes first evolved.
In exciting news, recent discoveries of fossils in North China by a group of researchers led by Prof. ZHU Maoyan from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences have shed some light on the early evolution of life on this planet, providing evidence that eukaryotes acquired multicellularity about 1.63 billion years ago.
This group of researchers discovered decimeter-sized eukaryotic fossils in the Yanshan area of North China earlier on. Their initial findings pushed back the emergence of multicellularity in eukaryotes by about 70 million years. However, the same team discovered 1.63 billion-year-old multicellular fossils from North China.
Implications of the billion-year-old fossils in the evolutionary process
“The newly discovered multicellular fossils come from the late Paleoproterozoic Chuanlinggou Formation that is about 1,635 million years old,” stated first author MIAO Lanyun in a press release.
“They are unbranched, uniseriate filaments composed of two to more than 20 large cylindrical or barrel-shaped cells with diameters of 20–194 μm and incomplete lengths up to 860 μm (micrometers). These filaments show a certain degree of complexity based on their morphological variation.”
The morphometric analysis of these filaments suggests that they represent a single biological species rather than a discrete species, as they show morphological continuity. The fossils were named Qingshania magnifica, 1989, a form taxon with similar morphology and size.
An important feature of the Qingshania is the round intracellular structure in some cells, which can be compared to the asexual spores known in many eukaryotic algae. This suggests a probability that the Qingshania is reproduced by spores.
MIAO added: “This indicates that Qingshania was most likely photosynthetic algae, probably belonging to the extinct stem group of Archaeplastida (a major group consisting of red algae, green algae, and land plants, as well as glaucophytes), although its exact affinity is still unclear.”
The oldest unambiguous eukaryotic fossils are unicellular, dating from about 1.65 billion years ago in Northern China and Northern Australia. Qingshania is known to have appeared slightly later than these unicellular forms, proving that eukaryotes certainly acquired simple multicellularity very early in their evolutionary process.
Source: Interesting Engineering
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North China unearths 1.63 billion-year-old multicellular fossils