Fossil records show that terrestrial vertebrates, including humans (that is, quadrupeds) differentiated from fleshfin fishes in bony fishes 360 million years ago. With the process of biological evolution, the diversity of fish meat quality is decreasing. There are only five kinds of fleshy bone fish living on the earth today, including three kinds of lungfish and two kinds of empty stickleback. A long-standing debate in academic circles is whether quadrupeds are more closely related to lungfish or empty spiny fish. In order to truly clarify the evolutionary model between quadrupeds and fish, the key is to fill the missing links in the evolutionary history through the new discovery of fossils.
The discoverers Zhu Min and Yu Xiaobo named this primitive fish Zhang's butterfly column fish. The genus name indicates that the primitive fleshy bone fish has a special lateral column on both sides of the sphenoid bone region of the skull, and the species name was given to their mentor, Academician Zhang Miman, a pioneer in the study of fleshy bone fish in China.
According to reports, in the discussion on the evolutionary relationship of fleshfin fish, although most hypotheses think that the first two groups are closer in quadrupeds, lungfish and stickleback, so far (q √): to. So far, no primitive fleshfin fish has been found to have the characteristics of the same ancestor of quadrupeds and lungfish. The discovery of butterfly column fish makes scientists have a fossil evidence closest to the ancestors of quadrupeds and lungfish, and also provides new important evidence for exploring the early evolutionary history of fish.
The researchers found that the butterfly column fish retained some features belonging to the spine type of fleshfin fish, such as the structure of the eye stalk and the lateral column of the sphenoid region of the head, and it also had some progressive features of quadrupeds or lungfish. On the basis of detailed comparative anatomical study, Zhu Min and Yu Xiaobo discussed the phylogenetic position of Guansuborder. The results showed that Diplodocus had a sister relationship with the ancestors of quadrupeds and lungfish. Butterfly column fish is more advanced than empty spiny fish, but more primitive than lungfish and quadrupeds. The discovery of butterfly column fish actually makes the evolutionary sequence between the backbone type of fleshfin fish and the backbone type of tetrapod or lungfish more continuous, which provides key data for solving the origin problem of lungfish and tetrapod and tracing the emergence sequence of important characteristics of these two groups.