Xi'an, October 28 (Reporter Alina) reporter learned from Northwest University on the 28th that the university's research team found the earliest known fossil of bryozoans (bryophytes) on the earth in Zhenba County, Shaanxi Province, and the study pushed the geological history of the moss phylum from the Pre-Ordovician to the early Days of the Cambrian Explosion, pushing its origin forward by about 50 million years.
The picture shows the earliest restoration of bryozoans. Courtesy of Northwestern University
The study further supports the "three-act Cambrian explosion" hypothesis proposed by ShuDegan's team, perfects the construction process of cambrian earth animal trees that lasted 40 million years, and effectively connects the explosive and phased fossil evidence chains of three animal subcategories (basic animals, protozoa and post-mouth animals).
According to reports, the Cambrian explosion is the most magnificent life explosion event of symmetrical animals on both sides known on Earth. Between 540 million and 518 million years ago, early ancestor representatives of almost all modern animals, including vertebrates, suddenly exploded in Earth's oceans. However, the very important animal phyla in geological history, the moss phylum, has always lacked a solid Cambrian fossil record. Their individual size, group life, modular growth, and ecological complexity have long been considered the product of ordovician radiation.
The figure shows the simulated restoration diagram. Courtesy of Northwestern University
The research team of Northwest University found millimeter-sized micro-fossilized stone in the biodestic limestone of the Xi artemisia section of the Xiaoyangba Section of the Xiaoyangba Formation in Zhenba County, Shaanxi Province, through acid etching experiments. After the preliminary research of the research group and the joint research of international scholars, it is believed that these microchemical stones are the earliest bryozoic fossils on the earth, revealing the Cambrian origin of this category.
After Bayesian and maximal minimalist branch systematic analysis of 52 features, 18 taxa and 2 outer groups, it is shown that cambrian bryozoan fossils are basal taxa of bryozoans, representing the most primitive ancestor types. This discovery pushes the origin of bryozoans forward by at least 50 million years.
The picture shows the section of Baxiaoyang Dam in Southern Shaanxi. Courtesy of Northwestern University
In addition, through scanning electron microscopy and X-ray tomography analysis, the research team believes that the multi-layered plasticity and complexity of the moss population originated 530 million years ago, elucidating important ecological innovations during the Cambrian explosion.
Bryozoans are tiny, with calcareous or chitinous chambers on the surface, and are typically shelled reef-building animals, usually living on other shell animals or hard-bottomed ocean surfaces. The fossil's discovery in the argillaceous limestone of southern Shaanxi suggests that Cambrian mosses are similar to later genera and are suitable for living in a clear hard-bottom environment. This reveals the reason for the lack of bryozoan fossils in the mud shale fossil pool. The study of such fossils is of great significance for understanding the evolution of the Earth's habitability and how benthic (grass-roots) animals have transformed and adapted the Earth.
The picture shows the research results sharing meeting. Photo by Alina
Shu Degan, an academician of the Chinese Academy of Sciences and a professor at the Department of Geology of Northwest University, said that the discovery of the source of the moss phylum in the strata 530 million years ago is very remarkable, requiring young people to have a solid basic knowledge and a tenacious spirit of exploration. At the same time, this event once again perfectly supports the correctness of the "three-act Cambrian explosion" hypothesis, or it further confirms that this hypothesis has reliable scientific predictability. (End)
Source: China News Network