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Disjunct intercontinental distributions have always fascinated biologists. With the increasing availability of molecular sequence data, there is a renewed interest in historical biogeography, especially in groups in which species boundaries have changed dramatically as a result, such as lichenized fungi. In the hyperdiverse family Parmeliaceae, Parmelina and Myelochroa have contrasting centres of distribution, with Myelochroa being most diverse in eastern Asia and Parmelina in Western Europe and the Mediterranean. We used multi-locus sequence data from 53 specimens to understand the impact of historical events on the current distribution patterns in these genera. We reconstructed phylogenetic relationships, estimated divergence times and inferred ancestral distributions. Our analyses suggested that the ancestor of the two genera occurred in the Old World and that these genera split during the Eocene. Diversification in both genera was estimated to have occurred during the Miocene, with the ancestor of Myelochroa probably occurring in Asia, whereas the ancestor of Parmelina probably occurred in the Turanian region and Europe or only Europe. The two Parmelina spp. occurring in the New World (P. coleae, P. yalungana) are not closely related and migrated independently from the Old World. [ABSTRACT FROM AUTHOR]

The genetic diversity and population structure of the foliose lichenized fungus Parmelina tiliacea has been analyzed through its geographical range, including samples from Macaronesia (Canary Islands), the Mediterranean, and Eurosiberia. DNA sequences from the nuclear ribosomal internal transcribed spacer, the mitochondrial large subunit ribosomal RNA gene, and the translation elongation factor 1-α were used as molecular markers. The haplotypes of the three markers and the molecular variance analyses of multilocus haplotypes showed the highest diversity in the Canary Islands, while restricted haplotypes occurred at high frequencies in Mediterranean coastal samples. The multilocus haplotypes formed three unevenly distributed clusters (clusters 1-3). In the Canary Islands all the haplotypes were present in a similar proportion, while the coastal Mediterranean sites had almost exclusively haplotypes of cluster 3; cluster 2 predominated in inland Mediterranean sites; and cluster 1 was more abundant in central and northern Europe (Eurosiberian area). The distribution of clusters is partially explained by climatic factors, and its interaction with local spatial structure, but much of the variation remains unexplained. The high frequency of individuals in the Canary Islands with haplotypes shared with other areas suggests that could be a refugium of genetic diversity, and the high frequency of individuals of the Mediterranean coastal sites with restricted haplotypes indicates that gene flow to contiguous areas may be restricted. This is significant for the selection of areas for conservation purposes, as those with most genetic variation may reflect historical factors and biological properties of the species. [ABSTRACT FROM AUTHOR]

Parmelina tiliacea is a common, widely distributed species in south-western Europe, easily identifiable by morphology and much used as an air pollution bioindicator in many regions. A molecular phylogenetic survey of samples from many geographical areas, using Maximum Parsimony and Bayesian inference of nuITS and mtLSU rDNA regions, revealed a group of samples geographically restricted to a small region of the Iberian Peninsula and genetically separated from the other P. tiliacea specimens studied. These samples are morphologically indistinguishable from P. tiliacea, apart from subtle anatomical characters in the ascomata (hyphae of the exciple and ascospore width), which are frequently absent. Although geographically different, the two taxa occupy similar habitats and are even sympatric in some areas, indicating that they do not exchange genetic material. This previously overlooked, and apparently endemic lineage, is described as P. cryptotiliacea sp. nov., and the name Lichen tiliaceus is epitypified by a sequenced specimen to fix the application of Parmelina tiliacea to the widespread genotype. A second unexpected result was the discovery that the morphologically distinct P. pastillifera was nested within P. tiliacea. These two cases stress the need to use molecular tools to elucidate species concepts even within widespread morphologically well-characterized macrolichens. Such investigations are necessary to improve our understanding and estimation of biodiversity, and to facilitate the development of sound biodiversity conservation strategies for lichens. [ABSTRACT FROM AUTHOR]

Morphological and phylogenetic relationships of the worldwide Mediterranean lichen forming fungus, Parmelina quercina, have been studied. Specimens from western Europe, western North America and southern Australia were analysed using molecular data (nuITS rDNA, nuLSU rDNA and mtSSU rDNA) and selected morphological features (upper cortex maculae, scanning electron microscopy examination of the epicortex, ascospores and conidia shape and size, and amphithecial retrorse rhizines). The results conclusively reveal that: (1) there is not one single species but four separate species in the Mediterranean or sub Mediterranean areas of the world. Parmelina quercina and Parmelina carporrhizans (Euroasiatic species), Parmelina coleae sp. nov. (North America) and Parmelina elixia sp. nov. (Australia); (2) largely debated P. carporrhizans is not a synonym of P. quercina but supported as a valid species circumscribed to Macaronesic relict sites; (3) the geographical isolation of the Australian population is correlated with a large genetic distance; (4) morphological characters (ascospores and conidial variability and thallus epicortex) correlate with the phylogenetic hypothesis; (5) the new or revalidated species within Parmelina quercina are not cryptic species but morphologically recognizable taxa. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 91, 455–467. [ABSTRACT FROM AUTHOR]