Does the "platypus ancient fish" 400 million years ago have anything to do with modern jawed animals including humans?
The latest collaborative study between Chinese and foreign scientists discovered and proposed a new framework for the early evolution of jawed vertebrates, which they believe are relatively close relatives in the history of biological evolution.
An international cooperative research team led by Zhu Youan, Lu Jing, and Zhu Min from the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, composed of scholars from China, Australia, the United Kingdom, and Sweden, conducted an in-depth study of the fossil specimens of the "platypus ancient fish" 400 million years ago. The research has made important progress, and his paper was published in the international professional academic journal "Contemporary Biology" on January 28, Beijing time.
Zhu Youan, the first author of the paper, said that most vertebrates, including humans themselves, belong to jawed vertebrates.
Modern jaws include cartilaginous fishes, bony fishes and descendants of the latter on land.
The space for system evolution from the origin of jaws to the appearance of the recent common ancestors of modern jaws is filled by a group of early jawed fishes collectively referred to as "scutellums". The common body blueprint of modern jaws and The origins of many important organ characteristics need to be found in the middle.
The Brindabella, nicknamed the "platypus ancient fish", is a medium-sized shield fish with a long and flat snout, which lived on the land surface of eastern Australia 400 million years ago. Shallow reef area.
In the latest international collaborative study, the researchers used high-precision CT scan data to scan and study two new Brindabella head specimens found in Australia and found that they were in an area unknown in the past. Inside, there are very important information hidden-the upper part (that is, the semicircular canal) and the lower part (that is, the vestibule, including the utricle and balloon) of the inner ear of the Brindabella fish are clearly demarcated, which is different from the inner ear of other scutellum fish known before Very different, and similar to modern jaws.
In fact, this series of characteristics can be found in most modern jaws, including humans.
The study also found that Brindabella has a well-developed endolymphatic sac. The endolymphatic sac is connected to the vestibule of the inner ear through a vertical small tube inward, and communicated with the outside by an endolymphatic vessel that penetrates the top of the skull. The modern jawed species, especially the basically consistent pattern with cartilaginous fish, further supports the closer relationship between the brindabella and the modern jawed species.
The corresponding author of the paper Lu Jing pointed out that there has been a long-standing debate on the evolutionary relationship of the earliest jaws. The latest research of Brindabella shows a new understanding of past classic specimens and an impact on the existing framework of early vertebrate evolution. .
(Video source: Guo Shihao, reporter from Institute of Ancient Spine, Chinese Academy of Sciences, Sun Zifa)
Editor in charge: [Li Yuxin]