Microstructure Of Micro-tubular Fossils From The Cambrian Qingxudong Formation In Songtao, Guizhou

After sampling the Cambrian Tsinghsutung Formation limestone system layer by layer from the Yantai section and the Caishichang section in Songtao,Guizhou,the tubular fossils obtained by acid foam treatment and thin sections have a total of 5 genera 7 Species:Mongolitubulus Missarzhevsky,1977,Byronia Matthews,1899,Sphenothallus Hall,1847,Hyolithellus Billings,1871 and Torellella Holm,1893.The distribution of the same molecules as the tubular fossils of the Tsinghsutung Formation in Songtao,Guizhou Province in the main landmass of the Cambrian is calculated.The fossils in this area are all calcium phosphates,which have preserved fine microstructures.We have conducted in-depth research on the microstructures of these fossils.The whole process of the growth and change of Mongolitubulus squamifer scales was discovered,and the width of the scales was measured to prove that there is a specific correlation between the size of the scales and the width of the tube.Given its controversial shell structure,combined with EDS composition analysis,it is believed that the original shell is a two-layer structure,and the filling of late diagenesis causes the middle layer.According to its microstructure characteristics,it is analyzed that its genetic relationship should be related to soft-body molting animals.By comparing with the shape and shell structure of the existing Scyphozoa,it is believed that the original shell wall of Byronia is a uniform multilayer shell wall stack structure with weak gaps between the layers.It is speculated that the tube body may be a highly mineralized hard body with a mechanism through its horizontal change and occurrence state,and it has strong repairability and environmental adaptability.Four fiber structures arranged in different ways in different parts of Sphenothallus were identified,which may be related to its complicated shell secretion.Restoring the thickening pattern and shell secretion pattern on both sides of the shell.Byronia and Sphenothallus with closed base found in the thin slices,combined with the specimens in previous literature,proposed that Cambrian cnidarians may not have sucker-like fixators budding phenomena.The slight difference between Torellella and Sphenothallus,which are similar in shape,is compared,indicating that the two may have different classification positions from the shell microstructure level.Distinguish the segmented growth pattern caused by four different conditions of Torellella.The relationship between the controversial Hyolithellus and Torellella is discussed.The tubular fossil discovered this time has improved the biological appearance of the small shell fossils of the Tsinghsutung Formation,expanded its geographic distribution of species,and provided new materials for microstructure and ecological research.The study of development and evolution has a particular significance.