Molecular systematics and species distribution of foliose lichens in the Gulf of Thailand mangroves with emphasis on Dirinaria picta species complex

Extensive surveys of mangrove foliose lichens in Caliciaceae and Physciaceae on the Gulf of Thailand revealed eight species of the genera Dirinaria, Physcia, and Pyxine. Species density was highest in the mid-intertidal zone (46%), followed by the landward and seaward zones (31% and 23%, respectively). Fifty-one new internal transcribed spacer sequences were generated and the resulting phylogenies based on maximum likelihood and Bayesian approaches yielded monophyletic lineages of all three genera. However, within the Dirinaria clade formation of polyphyletic assemblages among D. aegialita, D. applanata, and D. picta indicated the presence of homoplasies in certain morphological traits used to characterize them. To address species boundaries of these lichens in Dirinaria picta species complex, methods of DNA barcode-based delineation of putative species were employed. Additional sampling of the Dirinaria species from elsewhere is required to provide further insight into species delimitation of this heterogeneous genus.