Fossil specimens such as dinosaur egg fragments and eggshells found in Shanyang, Shaanxi and Laiyang, Shandong, about 80 million years ago. Photo by Sun Zifa, a reporter from China News Service
In recent years, the earliest fossils of broken eggshells about 80 million years ago found in Shanyang, Shaanxi and Laiyang, Shandong, who laid the eggs?
The latest research by Wang Xiaolin's team of researchers from the Institute of Paleontology and Paleoanthropology of the Chinese Academy of Sciences (Institute of Paleovertebrates of the Chinese Academy of Sciences) believes that they are less different from the Pingling stacked eggs of the dinosaur egg genus in the Nanxiong Basin of Guangdong Province, and are similar to the eggshells of the North American Raccopods, and it is speculated that their maternal dinosaurs may belong to the duckbill dinosaur family.
The paper on the latest research progress in the field of paleontological fossils was recently published online by the international professional academic journal "Historical Biology". The study also conducts an in-depth analysis of the fossil classification of dinosaur eggs in the round egg family, revises the taxonomic positions of other members of the round egg family in China and abroad, and also provides new evidence for the discussion of the mother of such dinosaur eggs.
Wang Qiang (left), associate researcher of the Institute of Paleovertebrates of the Chinese Academy of Sciences, and Zhu Xufeng, doctoral candidate, introduced the latest progress in dinosaur egg fossil research. Photo by Sun Zifa, a reporter from China News Service
There is less difference from the dinosaur egg flat ridge stacked egg
Wang Qiang, the corresponding author of the paper and an associate researcher of the Institute of Paleovertebrates of the Chinese Academy of Sciences, and Zhu Xufeng, the first author of the paper and a doctoral candidate of the Institute of Paleovertebrates of the Chinese Academy of Sciences, were interviewed by reporters in Beijing on the 20th on the latest research results.
Zhu Xufeng said that in recent years, the research team has collected a large number of dinosaur eggshell fragments in the Shanyang Basin of Shaanxi And the Laiyang Basin of Shandong, with fossil age of about 80 million to 66 million years.
When they studied the diversity of dinosaur eggs in various basins, they found some materials that could be compared with the Pingling stacked eggs of the dinosaur egg genus in the Nanxiong Basin of Guangdong Province. Through further research on the newly discovered dinosaur egg material and the original material of the Pingling stacked egg in Shaanxi, the research team found that the shaanxi dinosaur egg material in terms of eggshell decoration, eggshell microstructure mode, shell element morphology, stomata morphology, etc., compared with the original material of the Pingling laminated egg, these differences are not enough to establish new egg species, so the new dinosaur egg materials in these two locations in Shaanxi are classified as Pingling laminated eggs. The egg species has so far found very little fossil material in China, and lacks a complete egg body, which cannot be classified into the known egg family.
Zhu Xufeng, a doctoral student at the Institute of Paleovertebrates of the Chinese Academy of Sciences, demonstrated the research process of dinosaur egg fossils in the laboratory. Photo by Sun Zifa, a reporter from China News Service
It is very similar to the eggshell structure of the North American Mother Dragon Egg
Through in-depth comparative research, the research team also found that the two newly discovered dinosaur eggs in Shaanxi and Lu were not only less different from the Pingling laminated eggs, but also had very similar microstructural characteristics to the eggshells of the duckbill dinosaurs found in North America, which may be related to members of the duckbill dinosaur family.
Zhu Xufeng said that for a long time, the mother dragon egg has been used as a member of the round egg family, and the in-depth study of the Pingling laminated egg found in China shows that the shell of this type of egg is quite different from the round egg family and is not suitable for classification into the round egg family. Therefore, the latest study has revised the taxonomic positions of some members of the round egg family found in China and abroad, and also provides new evidence for the discussion of such dinosaur egg-laying mothers.
Pingling laminated eggshell fragments, a, b, c represent the materials of Nanxiong, Shanyang and Laiyang respectively. Photo courtesy of the research team
Revised dinosaur egg stacked egg genus and classification
As the most important result of this study, the research team of the Chinese Academy of Sciences completed the revision of the characteristics of the dinosaur egg stacked egg genus and revised the classification of the original related dinosaur egg fossils.
Previously, the Pingling laminated egg was classified as a large round egg family of dinosaur eggs. According to the analysis of the research team, there are great differences between the Pingling laminated egg and the large round egg family in terms of the degree of integration of the appearance decoration and shell unit, and it is not appropriate to place the Pingling laminated egg in the large round egg family.
Comparison of the microstructure of the Pingling laminated egg (top) with the diameter section of the round egg (bottom) of the general top round egg. Photo courtesy of the research team
Some dinosaur egg types that have been studied at home and abroad have described similar outer surface ornamentation and eggshell microstructure to Pingling laminated eggs, including the famous mother dragon eggs in the Upper Cretaceous of North America, which are often classified as round eggs.
Through the description and microscopic photos of these "round eggs" in Asia, North America and Europe, the research team found that these "round eggs" were quite different from the general top round eggs found in Laiyang, and it was difficult to classify them into the round egg family.
The research team specifically recommended that the round eggs of the mother dragon found in the Gobi Desert of the Mongolian plateau, the fine layered sub-round eggs of Shanyang in Shaanxi Province, and the unnamed round egg shells of the Jaisan Basin in Kazakhstan be classified as Pingling stacked eggs; the Alberta round eggs found in Alberta, Canada, and the Europa round eggs in Spain should be revised into members of the genus Laminated Eggs; and the North American Draco eggs were also classified as members of the genus Laminated Eggs.
Pingling laminated eggshell decoration and stomata opening characteristics, the upper, middle and lower materials are Nanxiong, Shanyang and Laiyang respectively. Photo courtesy of the research team
To lay the foundation for the study of dinosaur eggs and dinosaur relationships
Wang Qiang pointed out that it is very difficult to confirm the type of dinosaur eggs and their relationship with the egg-laying mother, and only a few types of dinosaur eggs can confirm their maternal dinosaurs, including long-shaped eggs (oviraptorosaurs) and prismatic eggs (wounded toothosaurs). Due to the close relationship between the Pingling laminated egg and the mother dragon egg, there is reason to believe that its maternal dinosaur may belong to the duck-billed dragon family.
He said that the study of the Institute of Paleovertebrates of the Chinese Academy of Sciences not only enriched the dinosaur egg species, clarified the distribution of the Pingling stacked eggs at home and abroad, but also further revised the classification location of some round egg dinosaur eggs abroad.
Microstructure of Pingling stacked eggs (upper and middle) and general top round egg (bottom) eggshell chord sections. Photo courtesy of the research team
Through this study, it is further clarified that when establishing the connection between dinosaur eggs and dinosaurs, it will be more based on looking for embryos in dinosaur eggs, or the close connection between dinosaur juveniles and dinosaur eggs in the same layer, "providing a good basis for us to establish the interrelationship between dinosaurs in different places, different layers and different eras in the entire Cretaceous period." Wang Qiang said.
(Source: China News Network)