The Doushantuo Formation in South China was deposited after the Nantuo glaciation but before the evolution of complex Ediacaran metazoans. It contains multiple taphonomic windows, in its cherts, carbonaceous shales, and phosphorites, onto the late Neoproterozoic biosphere. The phosphatic window is unusually clear; Doushantuo phosphorites at Weng’an (Guizhou Province) are known to exquisitely preserve a multitude of single-celled eukaryotes, muiticellular algae, and microscopic animals. Our recent survey reveals that, in addition to the now famous Weng’an locality, Doushantuo phosphorites at Baokang (Hubei), Chadian (Shaanxi), and Shangrao (Jiangxi) also contain diverse eukaryotes preserved at the cellular level. All these phosphorites were deposited in shallow-water environments, typically above fair weather wave base and close to ancient islands. Along with Doushantuo cherts and shales, these phosphorites give us a clearer and more complete picture of late Neoproterozoic biological evolution: there
Most previously reported Mesoproterozoic (1600-1000 Ma) fossils are from silicified carbonates, and they are commonly small in size (15-20 μm, ranging from coccoids to fila- ments 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.
