In the early morning of July 28th, the journal Science published a special academic comments on “Ultrastructure reveals ancestral vertebrate pharyngeal skeleton in yunnanozoans” co-authored by Northwest University’s Paleobiology Research Team, China University of Geosciences (Beijing), and Yuxi Normal University. The paper analyzes and challenges the core viewpoint proposed by certain scholars in a 2022 Science paper that stated “Yunnanozoans are stem vertebrates or primitive vertebrates.” NWU’s doctoral student He Kaiyue is the first author, with Liu Jianni and Han Jian as corresponding authors, and Northwest University as the first author’s affiliation.
In July 2022, certain scholars published a paper in the Science claiming to have discovered “distinctive” cellular-level microscopic structures in Yunnanozoans, which led them to infer that “Yunnanozoans belong to the stem vertebrates and are primitive vertebrates.” Over the past year, this viewpoint has sparked widespread discussions within the academic community. NWU’s Paleobiology Team argues that there are logical flaws in the scientific reasoning that led to this conclusion. The conclusion is primarily based on the so-called cellular-level microscopic structural “evidence” in Yunnanozoans while deliberately avoiding a thorough discussion of the macroscopic structural characteristics of Yunnanozoans’ organ systems, which contradicts the logical classification framework of evolutionary biology.
Academician of the Chinese Academy of Sciences and Professor of NWU’s Department of Geology, Shu Degan, introduced that “in terms of the evolutionary progression of the posterior branchial series, Yunnanozoans are at least four basic organ innovations (derived characters) lower than vertebrates. Currently, the only known stem group of vertebrates is the Myllokunmingiida, which is closely related to vertebrates because it already possesses the essential organ structures required by jawless fish, such as a cranial brain and eye, a single nostril and olfactory sac, primitive vertebral elements, a two-chambered heart, and complex myomeres.”
This paper is the 16th publication by NWU’s Paleobiology Research Team led by Academician Shu Degan since 1996 in journals such as Nature and Science.
