Scientists have unearthed the earliest example of a flower bud in a 164 million-year-old plant fossil in China. The discovery strongly pushes the emergence of flowering plants back in Jurassic period, between 145 million and 201 million years ago.
The fossil, which was unearthed in Inner Mongolia in China, is 1.7 inches (4.2 centimeters) long and 0.8 inches (2 cm) wide. It contains a stem, a leaf branch, an onion-shaped fruit and a small flower bud about 3 square millimeters in size. The researchers have named the new species Florigerminis jurassica.
There are two main types of plants: flowering plants, known as angiosperms, and non-flowering plants, known as gymnosperms. The flower bud and the fruit in the fossil are both clear indicators of that F. jurassica was an angiosperm and not a gymnosperm, which was the dominant plant type in Jurassic times. Until now, fossil evidence has shown that angiosperms did not occur before that Chalk period, between 66 million and 145 million years ago, but the new fossil is so far the most convincing proof that this was not the case.
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"Many paleobotanists are surprised [by the fossil], as it is completely different from what is written in books, "senior author Xin Wang, a researcher at the Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences (NIGPAS), told WordsSideKick.com in an email." But I am not. surprised, "he added.
The new fossil is not the oldest example of a petrified flower that has ever been discovered. In 2018, in a study published in eLife, researchers described 174 million-year-old flowers from a plant in the genus Nanjinganthus, also found in China, Live Science previously reported.
However, some researchers have questioned whether Nanjinganthus can really be considered an angiosperm because the flowers were not complex enough to distinguish them from leaf structures seen in gymnosperms, ScienceAlert reported. Flowers are also extremely delicate and difficult to fossilize, which can make it difficult to distinguish them from other plant material, Wang said.
But it proves the flower bud and the fruit of the new fossil without a doubt F. jurassica was definitely an angiosperm, he said. The fossil "therefore underscores the presence of angiosperms in the Jurassic and calls for a rethinking of angiosperm evolution," the researchers wrote in a statement.
Wang believes that several other known plant genera from the Jurassic period, including Nanjinganthus, Juraherba, Yuhania, Jurafruitus, Xingxueanthus and Schmeissneria, could also potentially be angiosperms, but he says there is no way to say it for sure without fossil evidence. Until now, scientists had simply assumed that these genera were gymnosperms because they originated in law.
But if angiosperms were present during the Jurassic, they would have been very unusual compared to gymnosperms and geographically isolated, making it very unlikely to find similar well-preserved examples of other flower buds, he said.
Alternatively, it is also possible to F. jurassica may be one of the very first evolutionary compounds between older angiosperm-like plants, such as Nanjinganthus, and newer true angiosperms found in the Cretaceous, Wang said.
The study was published online Jan. 6 in the Journal of the Geological Society of London.
Originally published on Live Science.