13 / 2025-03-22 10:20:05

Diversification of Tropical Climbers in the Middle Paleocene of South China ——Fossil Evidence from the middle Paleocene Sanshui Basin, Guangdong, China

Climbing plants,Icacinaceae,Menispermaceae,Paleocene,Sanshui

Theme 3: Earth-Life Co-evolution Through Time > Session 3i: Terrestrial Extinction Events and Their Driving Mechanisms in Earth History

    The climbing plants are iconic members of modern tropical and subtropical forests, contributing significantly to species diversity and overall ecosystem function. Icacinaceae and Menispermaceae, as characteristic families of climbers, not only play a key role in these modern forests, but also diagnostic groups of the Boreotropical flora during the Paleogene. Although climbing plants are widely documented throughout the geobiological history, their fossil records in the low latitude of the Paleogene Asia are still poorly understood. The middle Paleocene Sanshui Flora, situated in Guangdong, South China, is known for the presence of climbing plants, previously reported climbers includes Lygodium sanshuiense Naugolnykh, Tu, Liu et Jin, Paleoobiculare microcarpum Han, Stephania geniculata Han and Stephania ornamenta Han. Here, we report a diverse assemblage of climbers, especially woody climbers (lianas) from the middle Paleocene Sanshui Flora in Guangdong, South China, including Icacinaceae seed fossils representing 6 species of 3 genera, including Iodes, Paleophytocrene and Icacinicaryites, as well as new Menispermaceae seed fossils representing 2 new species of 2 genera, including Stephania and Diploclisia along with one additional leaf fossil of Menispermites.

    Climbers serve as niche reconstructors in the restoration of modern tropical forests, dramatically increase during the early to middle succession stages. Fossil evidences reveals that climbing plants, especially Icacinaceae and Menispermaceae underwent rapid global expansion during the Paleogene, filled the ecological vacancies created by the Cretaceous-Paleogene (K-Pg) mass extinction event and potentially set the stages for the development of diverse modern tropical forests. These various new fossils from the middle Paleocene Sanshui Flora here enhanced our understanding of the diversity of the climbing plants in Southern Asia during the middle Paleocene, and suggested tropical forest in East Asia during this period.