Kawinnat Buaruang

Evolution of complex symbiotic relationships in a morphologically derived family of lichen-forming fungi.

We studied the evolutionary history of the Parmeliaceae (Lecanoromycetes, Ascomycota), one of the largest families of lichen-forming fungi with complex and variable morphologies, also including several lichenicolous fungi. We assembled a six-locus data set including nuclear, mitochondrial and low-copy protein-coding genes from 293 operational taxonomic units (OTUs). The lichenicolous lifestyle originated independently three times in lichenized ancestors within Parmeliaceae, and a new generic name is introduced for one of these fungi. In all cases, the independent origins occurred c. 24 million yr ago. Further, we show that the Paleocene, Eocene and Oligocene were key periods when diversification of major lineages within Parmeliaceae occurred, with subsequent radiations occurring primarily during the Oligocene and Miocene. Our phylogenetic hypothesis supports the independent origin of lichenicolous fungi associated with climatic shifts at the Oligocene-Miocene boundary. Moreover, diversification bursts at different times may be crucial factors driving the diversification of Parmeliaceae. Additionally, our study provides novel insight into evolutionary relationships in this large and diverse family of lichen-forming ascomycetes.

Diversity and phylogenetic survey of cyanobacterial lichens (Collematineae, Ascomycota) in mangrove forests of eastern Thailand

Abstract Peltigeralean lichenized fungi were surveyed in the mangroves of Trat Province at the eastern coast of Thailand. Eleven species were found belonging to the genera Coccocarpia, Lepidocollema, Leptogium and Physma. Among them, the genus Coccocarpia was most abundant and diverse. Lepidocollema wainioi was also recorded here from Thailand for the first time. Based on the current classification of the peltigeralean fungi the phylogenetic placement of the suborder Collematineae was evaluated using a combined dataset of nuclear ITS and mitochondrial SSU rDNA sequences. Phylogenetic analyses using maximum likelihood and Bayesian approaches revealed issues with the species delimitation in the genera Coccocarpia and Lepidocollema, where the data indicated non-monophyletic lineages. Additional studies with extended sampling will be necessary to address species boundaries in these lichens.