Abstract Detail

Systematics Section/ASPT

Chung, Kuo-Fang [1], Leong, Wai-Chao [1], Liu, Yan [2], Rubite, Rosario Rivera [3], Repin, Rimi [4], Peng, Ching-I [5].

Phylogenetic affinity of the enigmatic Begonia sinofloribunda sheds light on the evolution ofSino-Vietnamese limestone flora.

Begonia sinofloribundais a rare limestone species distributed in the bordering area of northern Vietnam and southern China (Sino-Vietnamese), a region renowned for its vast and spectacular karst terrains and high plant diversity and endemism. Previously taxonomic accounts had variously placed B.sinofloribunda in sections Platycentrum, Diploclinium, and Petermannia, causing much confusion regarding its evolutionary origins. To test these different taxonomic hypotheses,molecular phylogeny based on nuclear ITS and chloroplast rpL16 genes are reconstructed, sampling 94 Asian Begonia species from all major clades identified by recent molecular studies. The sampling further increases the presences of Chinese limestone species that were very poorly represented in previous phylogenetic studies. To our surprise, except for the deciduous B. chingii, all sampled Chinese limestone species are grouped in a highly supported clade with B. sinofloribunda nested within it. This limestone clade, comprising mainly species of sect. Coelocentrum, also includes other Sino-Vietnamese limestone Begonia of sects. Diploclinium and Leprosae. Divergent-time estimates using BEAST, calibrated by the crown age of Asian Begonia, suggest a late Miocene (8.4 Ma;5.32-11.7 Ma HPD) diversification within this Sino-Vietnamese limestone clade, coinciding with the period of extensive karstification of the areas.Interestingly, there is a ca. 2 Ma gap between the stem and crown age of this clade. Our results suggest a single evolutionary invasion into the limestone habitats by the non-deciduous Sino-Vietnamese Begonia species.

Broader Impacts:

1 - National Taiwan University, School of Forestry and Resource Conservation, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan
2 - Guangxi Zhuangzu Autonomous Region and the Chinese Academy of Sciences, Guangxi Institute of Botany, Guilin, 541006, China
3 - University of the Philippines in Manila, Department of Biology, Manila, 1000, Philippines
4 - Sabah Park, P.O. Box 10626, Kota Kinabalu, Sabah, 88806, Malaysia
5 - Academia Sinica, Biodiversity Research Center, 128 Academia Road, Section 2, Taipei, 115, Taiwan

Keywords:
Begoniaceae
Limestone
speciation
molecular dating
Flora of China.

Presentation Type: Oral Paper:Papers for Sections
Session: 18
Location: Franklin A/Hyatt
Date: Monday, July 9th, 2012
Time: 3:45 PM
Number: 18009
Abstract ID:1022