中国科学院南京地质古生物研究所机构知识库

Most previously reported Mesoproterozoic (1600-1000 Ma) fossils are from silicified carbonates, and they are commonly small in size (15-20 mum), ranging from coccoids to filaments in morphology. Many of them can be interpreted as cyanobacteria. Carbonaceous shales represent another source of palaeontological information of the Mesoproterozoic biosphere. Sphaeromorphic and acanthomorphic acritarchs, as well as filamentous fossils, are common in many Mesoproterozoic shales. Here we report an unusual assemblage of tubular fossils from the Meosproterozoic Ruyang Group in Shanxi, North China. Some of these tubes are branched. Others bear annular-helical thickening that might be represented by one extinct algae to adapt-to a desiccating environment.