Microstructure of Mongolitubulus squamifer from the Cambrian Tsinghsu-tung Formation of Songtao, Guizhou
Article
Figures
Metrics
Preview PDF
Reference
Related
Cited by
Materials
Abstract:
Microstructures of the small shelly fossils of Mongolitubulus squamifer from the Cambrian Tsinghsutung Formation in Songtao, Guizhou province, were studied. Our results show that M. squamifer has extensive longitudinal fiber structure on both inner walls and outer walls, which may explain the tube's outer wall's widespread longitudinal cracking. In a specimen with well-preserved part below the round oval scales, we found that the exterior wall scales transform from punctate grains to irregular scales at the lower part of the base. They gradually form regular triangular scales at the upper part of the tube body. By measuring some of the reported tube width and scale width of M. squamifer, we found normal spines, and the scale size increased with the increase of tube width. The M. Squamifer in Songtao was usually observed with two major layers, in-cluding a dense with scales with outer and inner longitudinal fiberstructure. The development gap between the tubular body results in the outer tube is easily damaged. In some specimens, the interlaminar voids near the base fracture are quickly filled by secondary minerals, resulting in the loss of the thickened and dense fiber structure of the inner layer or forming an inter-mediate filling layer. The study revealed the scale arrangement characteristics and shell microstructure of M. squamifer, providing new information to explore the species' phylogenetic affinities further.
