Ruth del Prado

Remototrachyna, a newly recognized tropical lineage of lichens in the Hypotrachyna clade (Parmeliaceae, Ascomycota), originated in the Indian subcontinent

Biogeographical studies of lichens used to be complicated because of the large distribution ranges of many species. Molecular systematics has revitalized lichen biogeography by improving species delimitation and providing better information about species range limitations. This study focuses on the major clade of tropical parmelioid lichens, which share a chemical feature, the presence of isolichenan in the cell wall, and a morphological feature, microscopic pores in the uppermost layer. Our previous phylogenetic studies revealed that the largest genus in this clade, Hypotrachyna, is polyphyletic with a clade mainly distributed in South and East Asia clustering distant from the core of the genus. To divide the Hypotrachyna clade into monophyletic groups and to reevaluate morphological and chemical characters in a phylogenetic context, we sampled ITS, nuclear large subunit (nuLSU) and mitochondrial small subunit (mtSSU) rDNA sequences from 77 species. We are erecting the new genus Remototrachyna for a core group of 15 former Hypotrachyna species. The segregation of Remototrachyna from Hypotrachyna receives support from morphological and chemical data, as well from maximum parsimony, maximum likelihood, and Bayesian phylogenetic analyses of the DNA. We used a likelihood approach to study the geographic range evolution of Remototrachyna and Bulbothrix, which are sister groups. This analysis suggests that the ancestral range of Remototrachyna was restricted to India and that subsequent long-distance dispersal is responsible for the pantropical occurrence of two species of Remototrachyna.

Repeated evolution of closed fruiting bodies is linked to ascoma development in the largest group of lichenized fungi (Lecanoromycetes, Ascomycota).

Fruiting bodies are responsible for the effective dispersal of meiospores in ascomycetes. Different fruiting body types include open (apothecia) or closed (perithecia, cleistothecia) forms, which have traditionally been used as key paradigms for ascomycete classification. Molecular phylogenies show that most fruiting body types have multiple phylogenetic origins within the phylum, and are not suitable for the circumscription of classes. One exception are perithecia that are restricted in non-lichenized fungi to the monophyletic class Sordariomycetes. However, lichenized fungi with perithecioid fruiting bodies were found to belong to three other classes unrelated to Sordariomycetes. One of these is Lecanoromycetes, which includes the bulk of lichenized fungi. To understand the evolution of perithecioid fruiting bodies in the mostly apotheciate Lecanoromycetes, we assembled a combined data set of nuclear and mitochondrial ribosomal, and RPB1 DNA sequences, and traced the evolution of two morphological characters (fruiting body type and fruiting body development). We reconstructed ancestral character states using maximum likelihood and Bayesian methods. Additionally, we tested for correlation of character changes in a combined Bayesian/maximum likelihood framework. The results suggest that perithecia have evolved in unrelated groups of lichen-forming fungi. Within Lecanoromycetes they have evolved independently several times from apotheciate ancestors. Further, our analyses support a correlation between the type of fruiting body and the type of ascoma ontogeny. The evolution of angiocarpous ascoma development in Lecanoromycetes is a pre-adaptation for the repeated gain of perithecia. This finding is consistent with the hypothesis of a neotenic origin of perithecioid fruiting bodies in Lecanoromycetes.

Molecular phylogeny and historical biogeography of the lichen-forming fungal genus Flavoparmelia (Ascomycota: Parmeliaceae)

The lichen-forming fungal genus Flavoparmelia includes species with distinct distribution patterns, including subcos- mopolitan, restricted, and disjunct species. We used a dataset of nuclear ITS and LSU ribosomal DNA including 51 specimens to understand the influence of historical events on the current distribution patterns in the genus. We employed Bayesian, maxi- mum likelihood and maximum parsimony approaches for phylogenetic analyses, a likelihood-based approach to ancestral area reconstruction, and a Bayesian approach to estimate divergence times of major lineages within the genus. We identified two major clades in the genus, one of them separating into two subclades and one of those into four groups. Several of the groups and clades have restricted geographical ranges in the Southern Hemisphere, but two groups include species with wider distribution areas. Our analyses suggest that the genus originated in southern South America during the Eocene-Oligocene transition and that the diversification of the Australasian groups occurred recently. The subcosmopolitan distribution of species is explained by long-distance dispersal, while vicariance probably played a major role in the origin of the genus. Several currently accepted species were found to be non-monophyletic, indicating that the species delimitation in the genus requires further studies.

Gregorella , a new genus to accommodate Moelleropsis humida and a molecular phylogeny of Arctomiaceae

The phylogenetic position of the European crustose pioneer lichen Moelleropsis ( Biatora ) humida (Kullhem) Coppins & P. M. Jorg. is studied using partial sequences of the mitochondrial SSU and nuclear LSU rDNA of 64 ascomycetes, including sequences of all known species of Arctomiaceae . The analysis places M. humida in the Arctomiaceae with strong support as sister to the Tasmanian genus Wawea . The genus Arctomia is monophyletic and sister-group to the Wawea + Moelleropsis humida clade. The new genus Gregorella is described to accommodate Moelleropsis humida and the new combination Gregorella humida (Kullhem) Lumbsch is proposed. The ontogeny of the ascomata of Gregorella humida is similar to that of other Arctomiaceae , in that the generative tissue is formed on a thallus outgrowth. The Arctomiaceae did not cluster with the bulk of cyanobacterial lichens in the Lecanorales suborder Peltigerineae (or Peltigerales ), but is part of Ostropomycetidae. The closest relative of Arctomiaceae could not be identified, since the relationships of major clades within Ostropomycetidae lacked support.

A discussion about reproductive modes of Pseudevernia furfuracea based on phylogenetic data

Two asexual reproductive strategies of the common lichen Pseudevernia furfuracea are described. Although the species propagates mainly by isidia, some specimens also show the development of soralia. Morphological, chemical and molecular analyses were performed on three such sorediate specimens from the Canary Islands, Morocco and Turkey. Maximum parsimony, maximum likelihood and Bayesian analyses indicate that: a) sorediate samples represent only a morphological variant of the reproductive mode and b) the separation of taxa (at species level or below) on the basis of their containing either olivetoric acid or physodic and oxyphysodic acids is not appropriate. In addition, a phylogenetic reconstruction of the genus Pseudevernia is presented for the first time. The tree shows two sister monophyletic clades, one containing American species ( P. intensa , P. cladonia , P. consocians ), and the second encompassing the P. furfuracea samples (including sorediate specimens). The biological and taxonomic significance of soralia in sorediate samples is discussed.