Source: CCTV News
On the evening of October 27, Beijing time, the journal Nature published the latest results of Zhang Zhiliang and other doctoral students under the guidance of Professor Zhang Zhifei of the Early Life Research Team of Northwest University - "Fossil Evidence Reveals that the Moss Phylum originated in the Early Cambrian Period", announcing the discovery of the earliest known fossils of bryozoans (mosses) on the earth in Zhenba County, Shaanxi Province, which pushed forward the origin of bryozoans by at least 50 million years, further supporting the hypothesis of the "three-act Cambrian explosion" proposed by Academician Shu Degan's team It improves 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 sub-boundaries (basic animals, proto-mouthed animals and post-mouthed animals).
The Trilobite pseudo-Abeid worm and the tongue-shaped shell brachiopod Parabadiella-Eoobolus and their Cambrian global paleogeographic distribution contained in the Xi artemisia section of the Ba Dengying Formation in southern Shaanxi
The Cambrian explosion is the most magnificent event known on Earth for the eruption of life by symmetrical animals on both sides. 540-518 million years ago, early ancestor representatives of almost all modern animals, including vertebrates, suddenly appeared in Earth's oceans. However, the very important animal phyla in geological history, the bryozoic phylum, has always lacked a solid Cambrian fossil record, and their individuals are small, group life, modular growth, and ecological complexity, which have long been considered the product of ordovician radiation.
Simulate a restoration diagram
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 collaborative research of international scholars, it is believed that these microchemical stones are the earliest fossils of mosses 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 the Cambrian bryozoan fossil Protomelission is the basal taxon of bryozoans, representing the most primitive ancestor type. This discovery pushes the origin of bryozoans forward by at least 50 million years.
Earliest restoration of bryozoans
Through scanning electron microscopy (SEM and BSEM) and X-ray tomography (μ-CT) analysis, Zhang Zhiliang et al. believe that the multi-layered plasticity and complexity of the moss population originated 530 million years ago, elucidating important ecological innovations during the Cambrian explosion.
Lichen mosses 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.
Fossil scan details
Shu Degan, an academician of the Chinese Academy of Sciences, said, "This incident once again perfectly supports the correctness of the 'three-act Cambrian explosion' hypothesis we proposed, or it further confirms that this hypothesis has reliable scientific predictability." (Reporters Lei Kai and Yang Yutong)