Progress has been made in the formation of plant diversity and biogeography in Southeast Asia

Author: S. L. low, Xing Yaowu

Long term evolutionary history and short-term ecological processes often affect the distribution of biodiversity. Although tropical regions, such as Asia's Paleotropical flora, are extremely rich in biodiversity, the formation mechanism and driving factors of biodiversity are not clear. The genus Typhonium. S. (Araceae) has rich ecological habitats and is widely distributed in tropical and subtropical Asia. The center of species diversity within the genus is Indochina Peninsula, while the center of endemic species is Thailand. The species within the genus are widely distributed in the temperate areas in the east of the Himalayas, the West and northwest of China; It extends to Taiwan and the Japanese islands, and reaches Australia through the South Pacific. The tropical area of Southeast Asia is the diversity center of coleoptile, while there are few species in the adjacent areas. However, little is known about the rate and pattern of diversification of Coleoptera.

In order to understand the diversity rate and pattern of the genus cuspidus, the postdoctoral look Ling low of the Key Laboratory of tropical forest ecology, Xishuangbanna botanical garden, Chinese Academy of Sciences, carried out a series of studies with the co tutors, researcher Zhou zhekun and researcher Xing Yaowu, reconstructed the phylogenetic tree of the genus cuspidus through second-generation sequencing, and combined with biogeographic analysis, To explore the biogeographic history and differentiation mechanism of the genus Aconitum. At the same time, we can verify whether the diversity of Paleotropical Asia is caused by in-situ species formation or species infiltration in adjacent areas. It is found that the genus coleopia originated in the Indo China Peninsula in the early Miocene and differentiated rapidly after the climate was suitable in the Miocene. A large area of in situ speciation occurred in Indochina Peninsula. The diversity evolution analysis detected that the differentiation rate of coleopia increased significantly at 12 – 14 MA (12 – 14 million years ago), and many species formation events occurred in Indochina Peninsula, which may be related to the strengthening of Asian monsoon. The subsequent diffusion events from Indochina Peninsula to other regions suggested the historical pattern of "going out of Indochina Peninsula", accompanied by four sympatric species formation events. Therefore, the results support that Indochina Peninsula is the source of biodiversity in other Asian Paleotropical regions.

The results not only play a key role in the phylogenetic biogeography of Araceae, but also provide new insights into its evolutionary history. The relevant research results are entitled "extended Miocene specialty in and out of India: the biogeographic history of Typhonium sensu stricto (area) and its implication for the assembly of India flora", which was published as a cover paper in the third issue of Journal of systematics and evolution in 2021. Researcher Xing Yaowu of the Key Laboratory of tropical forest ecology in Xishuangbanna botanical garden is the corresponding author of the paper, and postdoctoral shook Ling low is the first author of the paper. The research work was supported by the research foundation for foreign young scholars of the National Natural Science Foundation of China (No. 31750110477), the 60th batch of Chinese doctoral Foundation (No. 2016m602731), the foundation of the Key Laboratory of tropical forest ecology of the Chinese Academy of Sciences (No. 09kf001b04) and the postdoctoral start-up fund of Xishuangbanna Tropical Botanical Garden.