Unveiling and Illustrating the Diversity of Lichen-Forming Fungal Species in Chile

Lichens are the emergent property of a symbiosis between a fungal partner and green alga or cyanobacterium. The taxonomy of lichenized fungi has traditionally relied on morphological or chemical traits of the lichen, but with the advent of DNA sequencing, researchers have increasingly integrated molecular data to test historical species concepts. Sticta and Podostictina, two genera of lichenized fungi, are diverse and often abundant in Chile, but the taxonomy of species occurring this region has not yet been tested within a molecular phylogenetic framework. Thus, this work aimed to investigate the diversity and species boundaries of Sticta and Podostictina that occur in continental Chile by sampling DNA and chemicals from both herbarium specimens and recent collections. Our phylogenetic analyses using the nuITS fungal DNA barcode inform the synonymizing of certain taxa, changing the generic placement of others, discovery of new records, and discovery of potentially new species. We reveal that Chile harbors at least 12 species of Sticta, including endemics, two species disjunct across the Americas, and seven species of Podostictina all restricted to southernmost South America. These findings highlight that lichen morphology can obscure the true phylogenetic diversity of lichenized fungi and that molecular inferences are critical to reveal the diversity and uniqueness of the Chilean lichen flora. A set of digital illustrations was also produced in conjunction with the ‘research-based’ component of this thesis project with the intent of connecting science and art. As lichens are often overlooked or not known at all to people, the illustrations sought to highlight morphological diversity and stimulate public interest, with the Sticta and Pseudocyphellaria s.l. (including Podostictina) as the subjects. These illustrations are displayed in a section of this thesis.