Chongqing specific buried fossil library
On September 28, Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences held a press conference on the research on major achievements of the source exploration of "From fish to humans". Upstream News Reporter Li Hongpeng Photo by
Do you believe that humans evolved from fish? On September 28, the top international academic journal Nature (Nature) published online four academic papers by Academician Zhu Min’s team of the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, focusing on the research results on the origin and earliest evolution of jaws.
On the same day, the reporter learned from the press conference on the "From Fish to Human" source exploration research held by of the Chinese Academy of Sciences that Academician Zhu Min's team discovered the "Chongqing Special Buried Fossil Library" and "Guizhou Shiqian Fossil Library" in the early strata of Chongqing, Guizhou and other places about 436 million years ago, adding another world-class special buried fossil library in my country, filling the gap in the global record of jaw fossils in the early Silurian period, and providing for the first time the rise of jaw and the earliest radiation differentiation.
, including humans, 99.8% of the existing vertebrates on the earth have jaws (maxillary and chin), collectively known as jawed vertebrates or jawed species. The emergence and rise of jaws is one of the most critical leaps in the history of vertebrate evolution from "fish to humans". Many important organs and body configurations of human beings can be traced back to the beginning of jaws' evolution. However, when, where and how did this leap happen? These problems have been plaguing paleontologists. The jaws did not have a relatively complete fossil record until the late Silurian period (425 million years ago), and the origin of the jaws by molecular clocks was no later than the late Ordovician period 450 million years ago. Therefore, there was a huge gap in the early evolution of jaws that lasted at least 30 million years and spanned the entire Silurian .
Academician Zhu Min said that the discovery of "Chongqing Special Buried Fossil Library" and "Guizhou Shiqian Fossil Library" have shown the appearance of the Silurian fish population, especially the jaw species, on a large scale in the history of paleontology, revealing the process of the rise of jaw species in the early jaw species: as late as 436 million years ago, various major groups of jaw species had flourished in South China; by the late Silurian period, more diverse and larger jaw species appeared and began to spread to the world, starting the process of fish landing and eventually evolving into humans.
According to reports, the fossil research of the "Chongqing Special Buried Fossil Library" and the "Guizhou Shiqian Fossil Library" traces many human-related anatomical structures to ancient fish 440 million years ago, filling the initial link in the evolutionary history of "From fish to human", updated the traditional understanding of the origin and rise of jaws, and further consolidated the evolutionary path of "From fish to human".
Academician Zhu Min said that the "Chongqing Special Buried Fossil Library" and the "Guizhou Shiqian Fossil Library" will continue to make continuous contributions to solving the mysteries surrounding the origins of jaws in the future.
News Depth
The prototype of human limbs, the direct ancestor of sharks
Can find clues in these new species
In the "Chongqing Special Buried Fossil Library", there are three new species of Silurian ancient fish that have been discovered: the magical Xiushan fish of shield skin fish, the creeping Shen fish of cartilage fish and the agile Tujia fish of armor fish. The
research team has been conducting meticulous research and repeated explorations through a variety of means including high-precision CT scanning, fine three-dimensional reconstruction, scanning electron microscopy element analysis, all-light image, and multivariate statistical analysis, which has made these fossils "expose" a large amount of precious anatomical information.
Shen's stalker
Confirmation shark evolved from the ancestor of "wearing a helmet and armor"
The stalker stalker stalker in the Chongqing biota is a cartilage fish. Early fossil records of cartilage fish are very rare, and are mainly microbody fossils. In the past, not only did Silurian cartilage fish not only not found in my country that had been related and preserved, but also the complete fossils of large cartilage fish in Devonian and later were very rare.The well-preserved Shen's sprigfish achieved a breakthrough in the discovery of large fossils of the Chinese Silurian- Devonian- cartilage fish. Not only that, it also became the earliest well-conserved large fossil of cartilage fish found in the world, making fossils from China the decisive evidence to reveal the origin of cartilage fish.
study shows that the body profile, general morphology and key characteristics of Shen's sprigfish are similar to those of early cartilage fish - sprigfish , but compared with other sprigfish , it is closer to typical cartilage fish such as sharks. It has very few spines, only at the front end of the dorsal fin. What is even more surprising is that Shen's sprig fish actually has a large bone plate that is only found in shield-skinned fish, which is continuously wrapped around the entire shoulder strap and back. This is a very primitive feature and has never been found in any cartilage fish or bone fish in the past. The discovery of Shen's sprigfish means that cartilage fish, such as sharks, rays, , and other cartilage fish, actually have direct ancestors who "wear helmets and armors".
Most of the entire history of paleontology, cartilage fish represented by sharks have been considered as the original state and evolutionary "prototype" of jawed vertebrates. Early researchers once believed that shield-skinned fish and boned fish might have originated from shark-like ancestors. A series of studies in recent years, especially the discovery of Shen's sprigfish, have strongly proved that the fact is exactly the opposite. The cartilage of sharks is secondary to degenerate, and cartilage fish originated from the "helmet and armor" shield-skinned fish.
Miracle Xiushan Fish
Human occipital bone evolved from the bone fragment of the head of the shield skin fish
Academician Zhu Min's team discovered another jawed fish in the Chongqing biota, called Miracle Xiushan Fish, which belongs to the shield skin fish.
Shield-skinned fish is a collection of primitive jawed species. They are between the jawless armored fish and the more advanced bone fish and cartilage fish . It has very important evolutionary significance for exploring the origin of jaw and jawed species. However, most shield-skinned fish were found in the Devonian strata in the past, and have been separated and specialized for more than 20 million years. There has been long been controversy about how many original jaw-like characteristics they still retain. Xiushan fish is very close to the origin of jawed species in the era. It cannot be classified into any known group of shield-skinned fish species in the past, but combines the characteristics of multiple " shield-skinned fish " categories. Therefore, the characteristics it shared with other later squid fish are likely to be the original characteristics of jaw species.
In addition, Xiushan Fish also has some characteristics that are of great evolution. For example, most jaws have movable cervical joints, while jawless fish have heads and body armor that are connected to their heads and cannot move. Although Xiushan fish has jaws, its neck is almost inactive. All Xiushan fish specimens showed a transverse crack in the middle of its head armor, which functionally compensated for the inmovable cervical joint, so that the head could be raised and fall during breathing and feeding. This fissure will form a new head-neck boundary in the bone fish, so that the bone fragments behind it can be separated from the cranial top. The occipital bone connected to the neck of the human being evolved from the bone fragments (central slices, or posterior parietal bones) in front of the fissure above the head of the Xiushan fish.
Lingdong Tujia Fish
The world's first armor fish fossil with a complete body
In the Chongqing special buried fossil group, the research team found the world's first armor fish fossil with a complete body and gave it a very vivid name - Lingdong Tujia Fish!
is named "Tujia", which is mainly taken from the fossil discovery place , Hunan Tujia and Miao Autonomous Prefecture, and , Xiushan Tujia and Miao Autonomous County, ; the species name "Singling", is taken from the posture of " carp jumping over the dragon gate" when it was buried after death, which is very agile. The discovery of the agile Tujia fish fully reveals the entire body of the armored fish for the first time.It has a rhombus-shaped inclined scales, a flat belly that adapts to benthic life. It also has anal cavity in the center of the abdomen, but no anal fins; the body has three dorsal fins, the first two dorsal fins are very close to each other, and has a fork-shaped lower tilt tail like the different turtles and flower-scale fish.
Researcher Gai Zhikun, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, said that a pair of ventral fin folds that run across the body were found on the abdomen of the Lingdong Tujia fish, extending from the back of the head to the tail tip. This is a huge surprise, because people have previously believed that armor fish have no paired fins at all, and research has shown that these continuous fin folds are the prototype of the limbs of tetrapods, including humans. This discovery not only provides key fossil evidence for the "fin fold theory" more than 100 years ago, but also highly consistent with data from modern molecular developmental biology. The cross-executing of the evidence of paleontological fossils with developmental biology has made the origin study of vertebrate paired appendages a classic case of evolution - developmental biology, just like jaw origin research.
research team used new technical methods such as computer fluid mechanics simulation experiments and trait big data to conduct a comprehensive analysis of the ventral fin folds of Tujia fish. Researchers said with emotion that the fish ancestors understood and used the "hydrotel" principle of modern hydrofoil ships in the early days of the Silurian period and were the first to evolve the world's oldest "hydrotel" structure, which was 436 million years earlier than humans invented the hydrofoil ship. For more than 400 million years, the paired appendages of vertebrates have undergone a series of evolutionary processes, such as paired fins to limbs, then from limbs to wings (birds), and even the limbs degenerate into "fins" (whales) or completely degenerate (snake). Researchers believe that the appendages evolved from fin folds of armored fish are the basis for today's movements of fish, terrestrial tetrapods, birds, whales, bats, and even humans.
Chongqing Morning Post·Upstream News Reporter Li Hongpeng
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