Wang Haibing exhibited and introduced the "Nine Buddha Hall Transmission Beast" orthographic specimen. Photo by Sun Zifa, a reporter from China News Service
Wang Haibing exhibited and introduced the "Nine Buddha Hall Transmission Beast" orthographic specimen. Photo by Sun Zifa, a reporter from China News Service
BEIJING, May 1 (Xinhua) -- The study of the early evolution of the auditory organs of mammals, including humans, has been attracting the attention of the paleontological community. Among them, Mai's cartilage, which plays an important role in the evolution of mammals, still has many unsolved mysteries, and it is expected that more fossil discovery studies will be solved.
"Nine Buddhas Hall Transmission Beast" orthodox specimen. Photo by Sun Zifa, a reporter from China News Service
Fossils of a new 120-million-year-old early euphropod were discovered
Wang Yuanqing's team from the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences (Institute of Paleovertebrates, Chinese Academy of Sciences), together with Peking University Stomatological Hospital and the United States, recently discovered a new species of early true mammals dating back about 120 million years in the fossil study of the Rehe biota in Liaoning, China, named "Nine Buddhas Tang Chuanchuan Beast".
The most important research result this time was the discovery of the ossified Myschonite preserved in the beast, which was slender and short, and was likely to lose a substantial connection with the middle ear hearing ossicles. This is the first time that the existence of ossified Myrdochrite cartilage has been found and confirmed in euphytes, filling the gap in the evolution of ossified Myrnelloy cartilage in early mammals, and also confirming that some adult individuals of early euphrodemia still retain relatively degenerate Ossified Mychondrine.
Wang Haibing introduced the fossil discovery and research results of the "Nine Buddha Hall Transmission Beast". Photo by Sun Zifa, a reporter from China News Service
This paper on the discovery and research results of important fossils in the evolution of early euparaths, which has recently been published in the international professional academic journal "Royal Society Philosophical Journal B", first reported the ossified Myrnellow cartilage and inner ear morphology in early euphrases, providing important evidence for the evolution of mammalian auditory organs.
Wang Haibing, the first author and corresponding author of the paper and an associate researcher at the Institute of Paleovertebrates of the Chinese Academy of Sciences, recently said in an exclusive interview with a reporter from the China News Agency in Beijing that true mammals are a branch of mammals, which contain all placental mammals such as humans and the fossil taxa closest to them. The name of the beast is dedicated to Li Chuankuo, a paleontologist at the Institute of Paleovertebrates of the Chinese Academy of Sciences, to commemorate his contribution to the study of early mammalian evolution.
The right jaw of the beast is yellow with ossified Mychonite cartilage and blue as hyoid bone. Courtesy of Wang Haibing
The aural evolution of the beast is the most hearing-hearing among mammals of its time
After a long period of meticulous repair of fossil specimens, high-precision computed tomography (CT) and comparative studies, the research team found that the morphology of ossified Myschondrium preserved in the Passing Beast was significantly different from that of the true trilodons and paraodonts of the same era, and it was the most degraded ossified Mystens cartilage known among Mesozoic mammals.
Wang Haibing pointed out that this indicates that the middle ear of the beast is likely to be completely detached from the lower jaw, representing a key node for the mammalian middle ear to break away from the lower jaw, reflecting the gradual degeneration of the mammalian Myrdochondrial. At the same time, the contact relationship between the ossified Mychonite preserved in the beast and the bones of the mandibular and middle ear also provides a more accurate reference standard for improving the definition of the various evolutionary stages of the mammalian middle ear.
Through high-precision scanning and analysis of the fossils of the beast, the inner ear morphology of the early Cretaceous true mammals was reconstructed for the first time. Courtesy of Wang Haibing
He said that the research team also reconstructed the inner ear morphology of the early Cretaceous true beast for the first time through high-precision scanning analysis of the fossils of the beast. The inner ear of the beast is relatively intact, and its morphology has both primitive and progressive characteristics, filling the gap in the evolution of the inner ear of the basal mammal and the late Cretaceous true beast. Among them, the volchlear curl of the passing beast is close to 360 degrees, which exceeds that of other mammals of the same era, and is close to most of the late Cretaceous true mammals, which also means that the aural evolution of the beast has the strongest hearing among contemporaneous mammals, so as to better prey and avoid danger.
The passing beast is a key node in the evolution of the mammalian middle ear out of the lower jaw
Regarding Mai's cartilage, Wang Haibing said that Mai's cartilage is common in the development of vertebrates, although its morphology and function are different in different taxa, but the ossification of Mai's cartilage in adult individuals has so far only been found in fossil mammals.
Ecological restoration map based on the fossil specimen of the "Nine Buddhas Hall Chuan Chuan Beast". Chen Yu draws photography
Embryonic development and fossil evidence suggest that Mychondrium plays an important role in mammalian evolution: in the evolution of the middle ear ossicles and mandibles, Mychondrium plays a role in supporting and stabilizing the ossicles until the middle ear is completely detached from the mandibular and stable at the base of the skull; the connection between the Myrnosk and the mandibular and middle ear bones is the core element defining the evolutionary stage of the middle ear in mammals, and it is also an important information reflecting the different evolutionary stages of early mammals.
At present, paleontologists have found ossified Mystenia cartilage in some primitive mammals of the Rehe biota (such as true trilobites, Zhanghe and mammals), which are closely connected to the ossicles of the middle ear, indicating that their middle ear is in the evolutionary stage of the transitional middle ear. The fossil study shows that in the evolution of mammals, the 120 million-year-old passerhead was a key node in the middle ear to break out of the jaw.
Wang Haibing believes that as one of the most important structures in the early evolution of mammals, the paleontological community still has limited understanding of its evolutionary process, and there are still problems such as whether the phenomenon of McCartilage ossification occurs in more mammalian taxa, and the degeneration mechanism of Mychondrium cartilage. He looks forward to more related fossil discoveries in the future and further in-depth research. (End)