The new hypothesis is expected to break the basic classification scheme that broke the century-old dinosaur

Recently, the British journal Nature published a fossil science paper proposing a new hypothesis related to the history of dinosaur evolutionary relations. This hypothesis challenges the stereotypes of academia for more than a century by proposing a fundamental new classification of dinosaurs into two new categories.

Any science is a process of continuous de-pseudo-existence, will the release of the new hypothesis of dinosaur evolution subvert the century-old established conclusion of dinosaur classification and reconstruct a new dinosaur phylogeny tree? Is the scientific basis reasonable and sufficient?

Break with centuries-old traditions

"The existing dinosaur classification scheme has been going on for a long time, and it should be said that no one has really doubted the existing scheme before this article. This is also the appeal of this article. For this new classification, Yu Luhai, a researcher at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, affirmed that this is an important progress in the field of dinosaur research so far, which breaks the traditional basic classification scheme of dinosaurs that has been used for a hundred years.

It is understood that for 130 years, dinosaurs have been divided into two major evolutionary branches: ornithischian dinosaurs whose pelvis is similar to birds, and sauropod dinosaurs whose pelvis is similar to reptiles. Ornithopod dinosaurs include ornithopod dinosaurs such as Iguanodon and armored dinosaurs such as Triceratops and Stegosaurus; sauropods include theropod dinosaurs such as Tyrannosaurus rex and sauropod dinosaurs.

In this work, the researchers studied early dinosaurs, including 74 taxa, analyzing a total of 457 dinosaur traits. Based on 21 traits that dinosaurs inherited from the same ancestor, scientists have identified a new branch of dinosaurs and grouped ornithopods and theropod dinosaurs into this branch, while sauropod dinosaurs were separated from an early carnivorous dinosaur known as Erelarosaurus.

To this end, Xu Xing, a paleontologist at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, said that this is a very interesting new dinosaur phylogenetic hypothesis, which is of great significance for people to understand the evolution of dinosaurs, and will affect all aspects of the academic community about the origin and early differentiation of the entire dinosaur taxon, including the origin of dinosaurs and the evolution of characteristics.

With the continuous emergence of new relevant fossil evidence, especially the gradual discovery of new fossils in the Triassic period, which is most closely related to the origin of dinosaurs, Xu Xing concluded that this conclusion will be further demonstrated, and his colleague Yuru Hai also said that dinosaur research is constantly promoted and developed.

The evidence is reasonable

As an important development, it means breaking the original deeply rooted concepts and research ideas, and is the scientific basis for supporting this conclusion reasonable?

In this regard, Yuruhai explained that the author did not make a breakthrough in "breaking the original idea", but found this new problem about the classification of dinosaurs in the process of studying related fossils. "It's the result of realizing this problem and studying it further."

"The new article's ideas are novel, and they are also in line with some new advances in dinosaur research in recent years, and I feel that the new classification system is more reasonable." Jiang Baoyu, an associate professor in the Department of Earth Sciences at Nanjing University, told reporters.

He judged this by two pieces of evidence, first of all, he used the example of ornithischian dinosaurs, indicating that they had a belt with a bird-like pubic bone backwards, which is similar to the theropod dinosaurs and birds that evolved into birds; in addition, in the past decade ornithopod dinosaurs and several ornithopod dinosaur branches, bird-like feather-like structures have been found, but no such structures have ever been found in sauropods.

"According to the new taxonomic system, feathers appear in the ornithopod and theropod families, and sauropods did not achieve this trait, which is more reasonable." Jiang Baoyu believes that if some anatomical features listed in the article are added, the new classification will be more reliable.

"At the heart of this study is the matrix constructed by the authors, which is a very complex process that includes many details such as the selection of the taxons and features used." Yuruhai deduced that this conclusion from the matrix constructed by the author was inevitable, and the advantage was that it was a matrix that could be constantly revised and falsified.

Yuruhai explained that the reason why it is said that "it is inevitable to reach this conclusion" is because the matrix of this article synthesizes the latest research results, mainly newly discovered fossils and new understanding of existing fossils, so it can be said that its conclusions have a basis and basis, and are constantly enriching and updating previous research.

Fossils are still insufficient

At present, all the evidence in support of the article is reasonable, but experts do not deny that some of the fossil evidence supporting this study is still insufficient.

"We must see that, as the title of the article says, this is still a hypothesis, because the authors also know that with the existing fossil material, the scientific basis is still insufficient, mainly due to the lack of early ornithischian dinosaur fossils." Yuruhai thinks it's safe to say that, at least for now, scholars are aware that the early evolution and taxonomic scheme of dinosaurs is still an unsolved problem.

"Judging from the data provided by the authors, most of the evidence comes from a very interesting class of ornithischian dinosaurs, that is, allodonosaur dinosaurs. However, such an important academic conclusion needs to be supported by more research. Xu Xing believes that the construction of dinosaur phylogeny trees is affected by many factors, including the selection of analytical objects, the selection of features and the correctness of coding. In addition, he believes that since the fossil record of early ornithischian dinosaurs is still relatively poor, this will be a factor that may affect the accurate reconstruction of dinosaur phylogeny trees.

"Any new theory or hypothesis will take time and more evidence to test, and hopefully subsequent studies will test this hypothesis." Jiang Baoyu said.

Indeed, human understanding of dinosaurs to date is far less abundant than expected, and many factors are uncertain. Wang Yuan, director of the China Paleozoological Museum, said that such results did not surprise him, because the phylogenetic research of dinosaurs has been doing, and some teams can change the entire classification system according to new characteristics. "These scholars are serious, but such results require more peer support and a test of time."