For the evolution of human beings, the public’s inherent impression is that they evolved from “apes”, but scientific research such as paleontology has found that the more ancient “ancestors” of apes, dinosaurs and other animals are actually “fish”. But how exactly did fish evolve into humans? Scientists from the Chinese Academy of Sciences have found more clues. From a 436-million-year-old fossil bank in Chongqing, the oldest jaw-like “Miracle Xiushanfish” fossil, unraveled the origin of the human “occipital bone”. The findings were published as a cover article in the international academic journal Nature, published on Thursday.
The Chinese Academy of Sciences pointed out that, including humans, 99.8% of the vertebrates on the earth have jaws (upper jaw and lower jaw), which are collectively referred to as “jawed vertebrates” or “jawed”. The emergence and rise of jaws is one of the most critical leaps in the evolution history of vertebrates from “fish to man”. Many important human organs and body structures can be traced back to the beginning of the evolution of jaws, but when and how “Leaping”, the currently discovered fossils can only confirm the existence of jaws in the late Silurian period regarding 425 million years ago, and the “molecular clock” (also known as genetic clock, evolutionary clock) infers that the origin of jaws is regarding 4.5 In the late Ordovician, 100 million years ago, there was a huge gap spanning the entire Silurian period for at least 30 million years.
South China or the entire evolutionary center of jawed fish
The team of Zhu Min, academician of the Chinese Academy of Sciences and researcher of the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, has visited more than 200 locations where fish may be contained in the Silurian strata in China in the past ten years. Abundant and complete fish fossils from the early Silurian period (436 million to 439 million years ago) were found in Qianxian. The team believes that the relevant discoveries reveal that South China is likely to be the evolutionary center of the entire jaws. At the latest 440 million years ago, jaws flourished in southern China, and even more diverse and larger jaws were found in the late Silurian. The species appeared and began to spread across the globe, initiating the process of fish landings and eventual evolution into humans.
Among them, a palm-sized fossil found in Chongqing contains dozens of clearly identifiable fish fossils, including the jawless armored fish “Smart Tujia Fish”, as well as jawed “Shen’s stickleback” and “Miracle” Xiushan Fish”. Miracle xiushan fish is a placode fish and is the oldest jaw-like fish discovered so far. A transverse fissure in the middle of its head carapace, which is similar in function to the neck joint, will form a new head-neck boundary in the bony fish that evolves later. Separated from the cranial roof (anterior ossicle), which eventually evolved into the human occipital bone.
It is the earliest and well-preserved cartilaginous fish known so far. It has the characteristics of the large shoulder and dorsal bone plate of placodes. It has never been found in any cartilaginous or bony fish in the past, which strongly proves that it is represented by sharks. Chondrichthyes originate from placodes. The flexible Tujia fish has a rudimentary even fin, providing key fossil evidence for the origin of paired appendages in vertebrates.
Originally published on AM730 https://www.am730.com.hk/China/436-million-year-old fish related to human occipital bone-Chinese scientists discover-fish become human-new evidence/340849?utm_source=yahoorss&utm_medium=referral
