Abstract Detail



Biogeography

ZUO, Lei [1], Freudenstein, John [2].

Eurasian continent vicariance shaped Asarum Sect. Heterotropa diversity and biogeography.

The “Sino-Japanese” Floristic Subkingdom is the east part of the East Asiatic Kingdom (also known as the “Sino-Japanese” floristic region), the modern center of floral biodiversity in the North Temperate Zone. This area extends from Eastern China to Japan through Taiwan and the Ryukyu Islands. Its population structure and species distribution have been deeply shaped by paleo-climatic and geological changes. While quite a few biogeographic studies have recovered dispersal patterns from the Eurasian continent to Japan and Taiwan Islands, few have explicitly explored the origin and connection of floristic evolution within the Taiwan-Ryukyu-Japan island arc, which harbors both high endemism and species diversity. To this end, we proposed three hypotheses: 1) the Taiwan origin hypothesis 2) the Ryukyu origin hypothesis and 3) the Japan origin hypothesis. In order to test our hypotheses, we selected Asarum Sect. Heterotropa whose distribution is strictly confined to this area. With DNA sequence data, we reconstructed phylogenetic trees, estimated timing of divergence, and inferred ancestral distributions. The results showed that: 1) those species in Asarum Sect. Heterotropa distributed on the island arc first diverged around 7.5 Ma and they form a sister group to those continental species; 2) Japanese species diverged first around 5 Ma and then the species on the Ryukyu Islands (3 Ma), following by the divergence on Taiwan (1 Ma). Our results indicate a tight association between geographic area and divergence events and also reveal a clear dispersal pattern from Japan through the Ryukyus to Taiwan, which strongly supports the Japan origin hypothesis and also highlights the importance of allopatric speciation in the diversification of species within the Taiwan-Ryukyu-Japan island arc.


1 - The Ohio State University, 1315 Kinnear Rd, Columbus, OH, 43212, United States
2 - OSU Herbarium, 1315 Kinnear Rd, Columbus, OH, 43212, United States

Keywords:
Asarum
Heterotropa
biogeography.

Presentation Type: Oral Paper
Number:
Abstract ID:746
Candidate for Awards:None


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