Un fossile du Permien pourrait révéler la plus ancienne structure connue de plantes à fleurs.

A new fossil discovery in China has challenged long-held assumptions about the origins of flowering plants, suggesting they may have originated much earlier than previously believed. Researchers have identified a Permian-era fossil, Permocarpelloides shuozhouensis, which exhibits features characteristic of flowering plants, potentially pushing back the timeline of angiosperm evolution by tens of millions of years. The fossil was discovered in the Lower Permian strata of the Shanxi Formation in Shuozhou, Shanxi province, China. It consists of a three-dimensional cast of three fruits, each containing multiple ovules or seeds of varying sizes. These structures are arranged in parallel, resembling three carpels from an apocarpous gynoecium, a configuration typically associated with the evolutionary lineage of magnolias. This finding is particularly significant because it aligns with expectations held by some botanists who consider magnolia-like ancestors as foundational to the development of flowering plants. For decades, scientists have struggled to locate evidence of flowering plants predating the Cretaceous period, which began around 145 million years ago. This gap in the fossil record led to the widespread belief that angiosperms could not have existed before this time. However, recent discoveries, including Taiyuanostachya, Yuzhoua, and Dengfengfructus, have hinted at the possibility of earlier angiosperm origins. Despite these findings, many botanists remained skeptical due to the absence of key features such as free carpels, structures considered ancestral in angiosperms. The newly described Permocarpelloides represents a breakthrough in this field. Its presence in the Early Permian, approximately 299 to 272 million years ago, suggests that flowering plants may have evolved far earlier than previously thought. The fossil's unique characteristics, including the arrangement of its fruits and the presence of enclosed ovules, provide compelling evidence supporting this hypothesis. Enclosed ovules, or angio-ovules, are a defining trait of angiosperms, distinguishing them from gymnosperms. The identification of such structures in a Permian fossil challenges the notion that angiosperms emerged only during the Cretaceous. The research team behind this discovery includes Qiang Fu, Weijia Huang, Jie Sun, and the author of the study. Their work builds upon the legacy of Dr. David L. Dilcher, a pioneering paleobotanist whose contributions to understanding early angiosperms were instrumental in shaping modern botanical science. The study was published in the journal Plant Biosystems, a publication affiliated with the Italian Botanical Society, which traces its roots back to 1716 and has played a crucial role in advancing botanical knowledge over centuries. This discovery has sparked renewed interest in the early history of flowering plants. By providing tangible evidence of angiosperms in the Permian, it opens new avenues for research into the evolutionary pathways that led to the diverse array of flowering plants present today. Scientists are now reevaluating the fossil record to determine whether other specimens might similarly challenge existing timelines. As researchers continue to analyze the implications of this find, the scientific community awaits further data that could refine or expand our understanding of angiosperm origins. The discovery of Permocarpelloides shuozhouensis marks a pivotal moment in paleobotany, offering fresh insights into one of the most enduring mysteries of plant evolution.