Transoceanic Dispersal and Subsequent Diversification on Separate Continents Shaped Diversity of the Xanthoparmelia pulla Group (Ascomycota)

Abstract

In traditional morphology-based concepts many species of lichenized fungi have world-wide distributions. Molecular data have revolutionized the species delimitation in lichens and have demonstrated that we underestimated the diversity of these organisms. The aim of this study is to explore the phylogeography and the evolutionary patterns of the Xanthoparmelia pulla group, a widespread group of one of largest genera of macrolichens. We used a dated phylogeny based on nuITS and nuLSU rDNA sequences and performed an ancestral range reconstruction to understand the processes and explain their current distribution, dating the divergence of the major lineages in the group. An inferred age of radiation of parmelioid lichens and the age of a Parmelia fossil were used as the calibration points for the phylogeny. The results show that many species of the X. pulla group as currently delimited are polyphyletic and five major lineages correlate with their geographical distribution and the biosynthetic pathways of secondary metabolites. South Africa is the area where the X. pulla group radiated during the Miocene times, and currently is the region with the highest genetic, morphological and chemical diversity. From this center of radiation the different lineages migrated by long-distance dispersal to others areas, where secondary radiations developed. The ancestral range reconstruction also detected that a secondary lineage migrated from Australia to South America via long-distance dispersal and subsequent continental radiation.

The lichen-forming fungi of the Xanthoparmelia pulla group (Parmeliaceae, Ascomycota) in Poland

“…The species is widespread almost worldwide. It occurs in Africa, Australia, Asia, South America and Europe [12]. In Europe it was reported from Belgium [22], Germany [23], Great Britain and Ireland [24], Greece [25], Italy [26], Montenegro [27], Netherlands [28], Spain and Portugal [29], Sweden, Norway and Finland [30].…”

“…Both species have different chemistry of thalli and in case of any doubts the specimens should be analyzed for the content of secondary metabolites. X. loxodes contains glomelliferic, glomellic, perlatolic acids and occasionally anziaic, stenosporic, loxodellic or gyrophoric acids [9,12,13] while in X. verruculifera divaricatic, nordivaricatic, oxostenosporic, stenosporic, subdivaricatic, perlatolic and 4-O-demethylstenosporic acids were found. Gyrophoric and lecanoric acids may also be present as accessory compounds [26].…”

“…Xanthoparmelia pulla group includes about 25 taxa dispersed throughout the world, seven of which occur in Europe [12]. Due to the frequent absence of apothecia and the lack of obvious differences in their structure, these taxa are traditionally distinguished on the basis of morphological features of the thallus, such as the color of lower cortex, shape of lobes and the presence or absence of vegetative propagules [12].…”

“…Due to the frequent absence of apothecia and the lack of obvious differences in their structure, these taxa are traditionally distinguished on the basis of morphological features of the thallus, such as the color of lower cortex, shape of lobes and the presence or absence of vegetative propagules [12]. However, chemical characteristics play the most important role in the identification of taxa [9,13].…”

“…Molecular studies have shown, however, that the genus Neofuscelia was polyphyletic, with its clades scattered within Xanthoparmelia. Consequently, the species of the genus Neofuscelia have been included in the Xanthoparmelia [11].Xanthoparmelia pulla group includes about 25 taxa dispersed throughout the world, seven of which occur in Europe [12]. Due to the frequent absence of apothecia and the lack of obvious differences in their structure, these taxa are traditionally distinguished on the basis of morphological features of the thallus, such as the color of lower cortex, shape of lobes and the presence or absence of vegetative propagules [12].…”