Questions Decoding the Year of the Rabbit | Li Qian: The Year of the Rabbit is about the rabbit, who is the "old ancestor" of the rabbit on earth?

　　Editor's note:

　　"All things greet the spring and send off the wax, and the end of the year is tonight."

The traditional Chinese Spring Festival of the Year of the Rabbit is approaching, and people who have been tested by the epidemic have hope.

Starting from January 18, 2023, China News Agency's "East and West Questions" column has launched a series of articles "Decoding the Year of the Rabbit" to explore the meaning and influence of Spring Festival culture and "Shuanglichun".

　　China News Agency, Beijing, January 21st, title: The Year of the Rabbit says the rabbit, who is the "old ancestor" of the rabbit on earth?

　　——Interview with Li Qian, a researcher at the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences

　　China News Agency reporter Sun Zifa

　　2023 is the traditional Chinese Year of the Rabbit.

Rabbits are very popular and loved by people because of their lively and active characteristics.

　　How did the cute rabbit originate and evolve?

This issue has always attracted the attention of the paleontological community, and it has also caused many controversies. Until the 1970s, the field investigation team of the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences (Institute of Paleontology, Chinese Academy of Sciences) investigated the strata about 62 million years ago in Qianshan, Anhui. The discovery and naming of the fossil of "Anhui model pika" confirmed that it was the ancestor type of rabbits, and only then did the debate on the origin of rabbits be quelled.

　　How did the Anhui pika become the "ancestor of rabbits"?

What kind of evolution process has it experienced since then?

What are the unsolved mysteries in the research?

On the occasion of the Year of the Rabbit, Li Qian, a researcher at the Institute of Paleospine of the Chinese Academy of Sciences, accepted an exclusive interview with China News Agency's "Dongxiwen" in Beijing.

The interview transcript is summarized as follows:

Video: [Dongxiwen] Li Qian: Fossils discovered in China provide key evidence for resolving the "pika homology" controversy

China News Agency reporter: What debates have there been in the paleontological field about the origin of rabbits?

What kind of key evidence does the discovery of Anhui pika fossils provide for the origin of rabbits and the homology of pikas?

Li Qian:

Rabbit is a small animal that everyone likes today. Although it is widely distributed in the world, its classification is not complicated.

In the history of paleontological research, there have been many controversies about the origin of rabbits, including that rabbits may be related to ankle joints, and rabbits may have originated from a group of creatures unique to Asia. , there was no consensus for a long time because of the lack of key fossil evidence.

The restoration map of the "rabbit ancestor" Anhui model pika 62 million years ago.

Photo provided by Institute of Paleontology, Chinese Academy of Sciences

　　It wasn't until the 1970s that the paleontological community had a new understanding of the origin of rabbits when the Anhui model pika fossils about 62 million years ago were discovered in the Qianshan Basin of Anhui, where the Chinese Academy of Sciences is located.

　　When the Anhui pika fossil was discovered, although the skull material was incomplete, its incisors, cheek teeth and other important structures were preserved, and some mandibular materials also provided very important features.

Through careful analysis and in-depth research, scientists found that the upper incisors of Anhui model pika are very similar to the structural features of today's rabbits, including two pairs of upper incisors, and the front pair can be seen to have longitudinal grooves on the surface when viewed from the front.

Based on the analysis of this series of structural features, scientists believe that the Anhui model pika is related to the living rabbits, representing the ancestor type of today's rabbits.

　　In the same basin where the Anhui model pika was discovered, another very important fossil named "Oriental pika" was also found.

The Anhui model pika has the characteristics of living rabbits and is related to today's rabbits, so it is the "rabbit ancestor".

　　These two types of fossils not only resemble rabbits and mice, but also have many intermingled features of "I am in you, and you are in me". This provides a very good fossil for solving the dispute of whether pikas are of the same origin Evidence, after comparative studies finally put forward the point of view of pika homology.

Fossil of the Anhui model pika from the "rabbit ancestor" 62 million years ago.

Photo by Sun Zifa

China News Agency reporter: How did the Anhui model pika evolve into today's rabbit?

From about 62 million years ago to the present, what are the important branch nodes in the evolution of rabbits?

What is the overall evolution trend?

Li Qian:

The Anhui model pika and the oriental pika, which are the ancestors of rabbits and mice respectively, were discovered at the same place about 62 million years ago, at the turn of the Paleocene and Eocene about 58 million years ago, Lagomorpha and rodents have been separated, began their own independent evolution.

　　On the whole, the distribution and evolution of rabbits on the earth is a relatively continuous process, but the time when they appeared on different continents is not consistent: the earliest lagomorphs fossil record in Asia is about 53 million years ago, and the earliest record in North America is about 53 million years ago. About 43 million years ago, Europe was relatively later, with reliable fossil records about 25 million years ago, and Africa was the latest, with the appearance of fossil lagomorphs only 19 million years ago.

　　China not only discovered the Anhui model pika fossils, but also discovered the earliest known lagomorpha fossils in the Early Eocene strata of Inner Mongolia about 53 million years ago. In the strata of the Pliocene (about 46 million to 43 million years ago), the earliest known leporid fossil was found-"Luohe Lushi rabbit".

Fossils of the "rabbit ancestor" Anhui model pika (right) 62 million years ago and ancient Dawson rabbit fossils 53 million years ago.

Photo by Sun Zifa

　　In addition, in the stratum about 30 million years ago in Inner Mongolia, where the ancient vertebra of the Chinese Academy of Sciences is located, a very well-preserved rabbit skeleton fossil was also collected, which was identified as the Ordos rabbit.

About 34 million years ago, there was a global cooling event on the earth. Mammals were also affected by this large cooling event. There was a very obvious mammal replacement event in East Asia, that is, after the cooling event Lagomorphs and rodents replaced Perissodactyla as the dominant taxa in the whole mammalian group.

Therefore, follow-up research on the lagomorph fossils discovered during this period will be of great significance for understanding how these groups adapt to climate change and the co-evolution of organisms and the environment.

　　It can be said that starting from the Anhui model pika, to the ancient Dawson rabbit, to the Luohe Lushi rabbit, and other very rich rabbit-shaped fossils, these materials make China have a relatively complete chain of fossil evidence for rabbit evolution, thus Made an irreplaceable and important contribution to the study of the origin and evolution of rabbits.

Researcher Li Qian showed and introduced the complete skeleton fossil material of a rabbit that was collected about 30 million years ago in the Inner Mongolia area and preserved the state when it was unearthed.

Photo by Sun Zifa

Reporter from China News Service: The discovery and in-depth study of the Anhui model pika fossil has put an end to the key disputes such as the origin of rabbits and the homology of pikas. Are there still unsolved mysteries in the field of research on the origin of rabbits?

Li Qian:

At present, in the field of research on the origin and evolution of rabbits, there are still many unsolved mysteries.

　　First of all, although the Anhui model pika is the "old ancestor" of rabbits, it has undoubtedly become the consensus of Chinese and foreign academic circles, but if we go back to the evolution source of the Anhui model pika, there is still no good fossil evidence to answer this question. A puzzle that scientists hope to explore and solve.

　　Secondly, although we have found the "rabbit ancestor" Anhui model pika 62 million years ago, there are also many early genera and species classified into the family Leporidae that were widely distributed in Eurasia, but the ancestors of modern rabbits lived in the Eurasian continent for a long time The record of inner Eurasia is missing, and they suddenly radiated in Asia and Europe about 8 million years ago. There is currently no clear understanding of this process, which scientists call the "rabbit event".

This issue is also very important to the origin of living rabbits, so it has become one of the key issues of rabbit evolution that paleontologists have been exploring.

　　Third, rabbits include Leporidae and Pikaidae. The early Pikaidae fossil materials discovered so far are very fragmented and scattered, and the origin of Pikaidae is still a mystery.

Although China has discovered a type of fossil material called the chain rabbit, whether it is the earliest fossil of the true pika and its origin are still controversial. It is hoped that more complete fossil materials can be found for research and determination.

　　The living pikas are distributed in large numbers on the Qinghai-Tibet Plateau in China. They are particularly sensitive to the environment and can be called the "barometer" of environmental changes, especially for today's biodiversity and environmental protection of the Qinghai-Tibet Plateau. They have important research significance.

For example, the Yili pika in Xinjiang has been listed as a second-class protected animal in the country.

Researcher Li Qian showed and introduced the ecological restoration map scientifically restored based on the research results of the "rabbit ancestor" Anhui pika fossils 62 million years ago.

Photo by Sun Zifa

China News Agency reporter: In the process of research on the origin and evolution of rabbits, what kind of cooperative research has been carried out by Chinese scientists and international counterparts?

What are the representative cooperation results?

What are the plans for future international collaborative research?

Li Qian:

In the study of the origin and evolution of rabbits, after the Institute of Paleospine of the Chinese Academy of Sciences discovered the Anhui pika fossil in the 1970s, it quickly carried out research work and brought the research results to international academic conferences and international cooperation and exchanges.

In the 1980s, Chinese scientists proposed the concept of "homologous pika" internationally, and presented it at international academic conferences, which immediately attracted widespread attention from the international academic community, especially experts and scholars studying lagomorphs and rodents.

　　In subsequent further research, China not only carried out morphological research on the origin and evolution of rabbits, but also participated in comprehensive research combining paleontological morphology with modern molecular biology.

Today, whether it is the morphological study of paleontology or the comprehensive study of modern molecular biology, the international academic community has recognized the concept of "homologous pika". The Anhui model pika is the "old ancestor" or ancestral type of rabbits. , has also become the consensus of the international academic community.

　　At the same time, because of the discovery of "rabbit ancestor" fossils in China, as well as relatively complete fossil evidence about rabbit evolution, this has also attracted many international colleagues to China to conduct relevant international cooperative research.

As mentioned earlier, there are still many unsolved mysteries in the field of research on the origin and evolution of rabbits. When solving these mysteries, the abundant and important rabbit fossil materials in China will be more attractive. I believe that there will be more in these fields in the future. The advancement of multi-international cooperation has produced more research results.

　　On the occasion of the coming of the Year of the Rabbit, the scientific research team of the Institute of Paleospine of the Chinese Academy of Sciences scientifically restored the image of the "rabbit ancestor" and completed the ecological restoration map based on the research results of the Anhui model pika fossil, showing the ecological environment of the buried hill basin 62 million years ago It has become the source of inspiration and design basis for the mascot "Rabbit Yuanyuan" of the CCTV Year of the Rabbit Spring Festival Gala. We also take this opportunity to wish everyone a happy and happy Chinese New Year in the Year of the Rabbit. .

(Finish)

Expert profile:

　　Li Qian, researcher, Ph.D., Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences (Institute of Paleontology, Chinese Academy of Sciences).

Mainly engaged in the research of Paleogene mammals and continental stratigraphy.

Focus on the taxonomy and systematics of small mammals (rodents, lagomorphs, etc.), the origin and evolution of species, and the co-evolution between mammals and paleoenvironments.

So far, she has published more than 70 research papers in international and domestic core journals. The main research achievements are as follows:

　　One is the first report of fossils of rodents and lagomorphs in many locations and horizons in China, providing a new understanding of the origin and evolution of different phyla, and further confirming the Asian origin of rodents.

Second, the continuous succession sequence of rodent fossils from the early Eocene to early Oligocene in East Asia was established for the first time, which clearly reflected the response of rodents to global climate and environmental changes in the same period; An important reference for stratigraphic division and comparison.

The third is to promote and solve the problem of comparison between Asian mammalian stages and North American and international stages, establish an age-calibrated Paleogene stratigraphic framework, and provide strong support for the construction of continental strata in China.