A diverse metaphyte assemblage from the Neoproterozoic black shales of South China

A fossil assemblage of diverse megascopic benthic algae is well preserved o n bedding planes in black siliceous shales of the Neoproterozoic Lantian Fo rmation (upper Sinian) at Lantian village, Xiuning county, Anhui Province, South China. Based on morphological differences, 12 taxa are recognized. Mo st specimens show both a holdfast and a vegetative thallus, some with dicho tomous branching, which reveals that they are multicellular benthic algae. Each type presents a certain morphological appearance, e.g., spheroidal - C huaria sp., filamentous - Doushantuophyton rigidulum, fan-like - Flabelloph yton lantianensis. Four to six different benthic forms and more than 15 ind ividuals are well preserved on the same bed with an area less than 150 cm(2 ). These confirm that a great morphological evolutionary radiation of seawe eds took place no later than the Lantian epoch, with an absolute age around 570 Ma. Growth cycles in Flabellophyton strigata n.sp. reveal that periodi cal events, such as seasonal variations, occurred in that epoch. A benthic assemblage consisting of three differentiated macroscopic remains is simila r to the Miaohe Biota reported from the Doushantuo Formation of the Yangtze Gorges 1200 km away, allowing biostratigraphic correlation of both of thes e Neoproterozoic Formations.