SG: Diversification within the plant genus Polyspora (Theaceae) in Sri Lanka

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Sri Lanka is renowned for its diverse and unique flora, with nearly 30% of flowering plant species found nowhere else. Most of this plant diversity is concentrated in the highlands in the south of the island. The flora of Sri Lanka is assumed to have a close affinity to the flora of the Western Ghats, and together these two regions comprise a recognized global biodiversity hotspot. This project will investigate species diversity within the plant genus Polyspora (Theaceae), a relative of tea, and use the group as a model to examine plant diversification within the Sri Lanka-Western Ghats region. This study will clarify the number of recognized species of Polyspora in Sri Lanka and map their patterns of distribution within the region. Comparative methods will be used to estimate when Sri Lankan Polyspora species diversified in the past, how their patterns of distribution have changed through time, and how their patterns of distribution are predicted to change in the future. This project will strengthen international collaborations among researchers from the US, Sri Lanka and India, and will increase participation in science of students from underrepresented groups in the USA. A species level phylogeny of the genus Polyspora using plastid and nuclear DNA sequences will be reconstructed and used to examine biogeographic relationships between both Sri Lanka and the Western Ghats, and within South Asia in general. Identification of the sister group and divergence time of the Sri Lankan Polyspora lineage will provide a context for diversification within Sri Lanka and address longstanding questions on the number, delimitation, and geographic distribution of genera in Thecae that will provide a framework for future floristic and taxonomic work in the family. A Single Nucleotide Polymorphism (SNP) analysis of 120 Polyspora accessions will be used to provide a fine-scale test of geographic structure within Sri Lanka. This phylogeographic analysis will then be used to clarify species limits within the genus and provide a context for future studies on speciation.