After a hundred years, the cinnamon plants have recognized their ancestors

In the mass extinction event at the end of the Permian period, the calabash plant disappeared.

Recently, an international team led by Wang Jun, a researcher at the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, discovered a large number of well-preserved fossils of Coccinellifolia in the "Plant Pompeii" in Wuhai, Inner Mongolia, and confirmed that they not only contain fern spores.

Provide opportunities to reveal past and present lives

It is reported that the Coccinelliforme includes more than 20 genera and more than 50 species.

"For a long time, the key to the failure to'recognize the ancestor and return to the ancestor' of the calabash is the lack of the overall shape and internal anatomical information of the plant.

In 2012, Wuhai "Plant Pompeii" was discovered and named by Wang Jun's team, and related research results were published in the Proceedings of the National Academy of Sciences (PNAS).

That year, with a huge volcanic eruption that suddenly occurred in the northwest of Wuda District, Wuhai City, hot volcanic ash fell and ended this once-prosperous forest kingdom.

The plant fossils preserved in these volcanic ash provide an opportunity to unravel one of the greatest mysteries of paleobotany-the past and present of the calamus.

Wang Jun’s team discovered that Paradingia wuhaia, a new species of the Coccinella family from the "Plant Pompeii" in Wuhai, Inner Mongolia, has both the reproduction mode of spore plants and the wood structure of gymnosperms, so it belongs to the typical predecessor.

"This discovery reveals an important link in the evolution of spore plants to seed plants, and completely solves the position of Coccinelliformes in the evolutionary tree of life, that is, the systematic classification attributes and their genetic relationships.

The former gymnosperms did not become extinct rapidly

The entire canopy of the “Wuhai pseudotooth” discovered this time has been preserved, and at the same time the appearance and internal structure of the reproductive ears and leaves are preserved, thanks to the new fossil production area of ​​Inner Mongolia’s Wuda Coalfield, the “Plant Pompeii”.

Through the overall restoration research of "Wuhai pseudodentate leaf", Wang Jun's team believes that its relationship with seed plants is closer than that of ferns, and that "Wuhai pseudodentate leaf" has evolved from leaves.

"Therefore, we can confirm that the'Wuhai Pseudotodaria' and the Coccinellidae belong to the pregynosperm.

Previous research found that the pregynosperm was extinct from the Middle Devonian 390 million years to the Late Carboniferous 310 million years, and it should now be the Middle Devonian-Carboniferous-end Permian.

Research by Wang Jun’s team showed that approximately 110 million years after seed plants were differentiated (360 million years in the Late Devonian), pregynosperms represented by Coccinelliformes continued to diversify until the end of the Permian.

In other words, during the Devonian-Carboniferous-Permian period, pregynosperms, the ancestors of seed plants, gradually became diversified after the earliest seed plants were differentiated, and independently developed reproductive organs similar to cones.

Although the reproductive capacity of Ecolliflora plants is very powerful, they were also victims of the effects of environmental and climate change during the mass extinction at the end of the Permian.
This mass extinction destroyed the global marsh ecosystems, and along with the disappearance of the environment on which the calabash order relied, the order also became extinct.

"Taxonomy Football" completes "Shooting goals"

The study by the Chinese Academy of Sciences Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences Institute of Botany, Shenyang Normal University, the University of Birmingham, Indiana University, University of Pennsylvania, Academy of Sciences of the Czech Geological Survey, West Bohemian Museum, Vienna University and other institutions in Austria Of the international research team.

Dr.
Jason Hilton from the University of Birmingham, who participated in the research, said that in the 1930s, when the calabash was first established, it was considered a unique plant population, but scientists regarded them as a "taxonomic football".
Kicked around on the court incessantly, but no one identified their role in the "story of life", and then completed the goal of "scoring shot classification".

Thanks to these complete and exquisite specimens from the "Plant Pompeii" in China, the research team was able to reconstruct the new species of "Wuhai Pseudodonta", a new species of Coccinellifolia, and finally ascertain the kinship of this group of plants Relationship and its important significance in life evolution.

Wang Jun pointed out that in addition to uncovering one of the biggest mysteries of paleobotany, the study also clarified the botanical classification position of the calabash order.
The determination of the classification position of the order of the caladium also represents a significant contribution of Chinese scholars to the taxonomy of paleoplants.

Prior to this, the four major botanical geographic regions of the world in the Late Paleozoic-Europe, America, Cathaysia, Angara, and Gondwana had established more than 40 plant groups.
Only the big feather fiddleheads were composed of the older generations such as Li Xingxue and Yao Zhaoqi.
Chinese scholars have established their systematic position based on the study of fossil materials in my country, and other research and establishment purposes are established by foreign researchers.

This research also provides important clues for tracing the roots of the "Cathaysia flora".
Wang Jun told reporters that the current results indicate that the Cathaysia flora may have originated in my country's Devonian flora, rather than the Carboniferous European and American flora previously known.

As we all know, coal is formed by plants, but it is not known what plant coal is formed.
Wang Jun said that the fossil collection and research of the "Plant Pompeii" answer this question.
So far, Wang Jun’s research team has accumulated more than 5,000 square meters of actual restoration data, which can not only intuitively illustrate the appearance of individual coal-forming plants, but also show the actual appearance of the largest area of ​​ancient coal-forming swamp forest.

Related paper information: https://doi.
org/10.
1073/pnas.
2013442118

Fossil of Pseudotodon in Wuhai (Photo courtesy of Nangu Institute)

Restored map of Wuhai pseudodentate leaf (photo courtesy of Nangu Institute)