María Inés Messuti

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.

Arbuscular Mycorrhizas and Dark Septate Fungi in Lycopodium paniculatum (Lycopodiaceae) and Equisetum bogotense (Equisetaceae) in a Valdivian Temperate Forest of Patagonia, Argentina

ABSTRACT Arbuscular mycorrhizas (AM) are one of the most widespread and common type of symbiotic associations. Lycopodium paniculatum and Equisetum bogotense are two important species of seedless vascular plants in a Valdivian temperate forest of Patagonia, Argentina. The mycorrhizal status of these species is completely unknown, as it is for most lycophytes and monilophytes in Argentina, where information on symbiotic interactions in these plants is scarce. In this study, typical AM structures were observed in sporophytes of L. paniculatum and E. bogotense. The percentage of root length colonized by AM fungi ranged from 0 to 50% in the first species and from 0 to 22.5% in E. bogotense. Both species were facultative mycorrhizal and it was observed that the habitat and substrate seem to play an important role in determining the colonization intensity. The morphological AM colonization pattern was considered an Intermediate-type. Dark septate fungi, characterized by septate hyphae and microsclerotia, were also present within the roots of L. paniculatum and E. bogotense.

Utility of nuclear SSU and LSU rDNA data sets to discover the ordinal placement of the Coccotremataceae (Ascomycota)

Abstract Informal ascomycete classifications have traditionally been based in part on ascomatal morphologies. The problems associated with grouping taxa using ascomatal characters are evidenced in the Coccotremataceae where the ascomata have been interpreted either as apothecia or perithecia. We used SSU rDNA sequences representing all classes of the Pezizomycotina to infer the phylogenetic position of the family. The Coccotremataceae clustered within the Lecanoromycetes. Since the Lecanoromycetes are characterized by the presence of apothecia, these data support the apothecial interpretation, given that the ascomata of the Coccotremataceae are not the result of convergent evolution. To evaluate the ordinal placement of the Coccotremataceae we used sequences of the SSU rRNA and LSU rRNA gene of 12 Lecanoromycetes. The SSU and LSU portions of this second analysis reveal conflicting phylogenies. Therefore we compared the two portions with additional statistical tests: splits decomposition, an analysis of the distribution of homoplasy, and a calculation of the ideal nucleotide substitution rate. In all of these tests the LSU data performed better than the SSU data. The results of the incongruence length difference (ILD) test suggest the data portions could be combined. There is no difference in the tree topology of the combined data set and of the LSU portion only, but the bootstrap values in the combined tree are lower. We argue that the low bootstrap supports in the combined tree are due to the phylogenetic signal in the SSU data set. Therefore we use the LSU and the combined tree to base our classification of the Coccotremataceae. In the LSU and the combined tree the inclusion of the Coccotremataceae in the Pertusariales is supported as is the sister relationship of the Pertusariales and Agyriales. Within the Pertusariales the Coccotremataceae and Pertusariaceae are well-supported sister taxa.

A survey of thelotremoid lichens (Ascomycota: Ostropales) in subantarctic regions excluding Tasmania

Thelotremoid lichens (Ostropales, Ascomycota) with a trentepohlioid photobiont in Tierra del Fuego, the Falkland Islands, the South Island of New Zealand, and subpolar islands of the southern Hemisphere are studied. Twenty-five species are accepted, with three species described as new to science: Melanotopelia blepharostoma Lumbsch & Divakar, Topeliopsis athallina Lumbsch & Mangold and Topeliopsis patagonica Mangold & Lumbsch. The new combination Topeliopsis novae- zelandiae (Szatala) Lumbsch & Mangold is proposed.

A new species of Hysterium from Patagonia, Argentina

Investigations of corticolous fungi in Patagonia have revealed the existence of a new species of Hysterium. H. andinense sp. nov. is described and compared to the related species. H. andicola is synonymized with H. insidens .

Noteworthy hysteriaceae from southern South America

Species of Gloniella, Glonium and Gloniopsis from southern South America were studied. A new fungus Glonium colihuae sp. nov., with hysterothecia is described from Argentina, Patagonia; Glonium chusqueae is synonymized with Gloniella lyphae; Gloniopsis argentinensis and Glonium costesi are validated, and some comments on the taxonomy and occurrence of Gloniopsis araucana, G. praelonga, Glonium abbreviatum and G. cumingii are presented.

Mycorrhizal Status of Obligate and Facultative Epiphytic Ferns in a Valdivian Temperate Forest of Patagonia, Argentina

Abstract Arbuscular mycorrhizae (AM) influence the growth, morphology and fitness of the plant species they colonize. Despite the abundance and importance of epiphytes in forest dynamics, little is known about AM in these plants. Abundant epiphytes are present in the Valdivian temperate forests of South America, where ferns are one of the most important components of the epiphytic vascular flora. The aim of this work was to analyze the occurrence of AM in sporophytes of obligate and facultative epiphytic fern species in a Valdivian temperate forest of Patagonia, Argentina. We examined the roots of 10 epiphytic fern species. Roots of 66 sporophytes were collected from tree trunks and branches between 0.5 and 2 m height above the ground and were stained by using a modified Phillips and Hayman (1970) method. Of the 10 species examined in the present study two were found to be obligate epiphytes, six were facultative epiphytes and two could not be classified because few individuals were found. Most of them lacked AM structures, except for seven Hymenophyllum sporophytes which were rooted in soil and possessed scarce knobby hyphae and structures similar to coils and vesicles. Abundant dark septate fungi were observed within the cortex of all samples. The absence of AM in epiphytes may be explained by different ecological or taxonomic reasons, but in this study we suggest that root morphology may be an important factor influencing mycorrhizal behavior in ferns.

New or Overlooked Species in the Lecanora subfusca Group from Southwestern North America (Lecanorales, Ascomycotina)

Abstract The new species, L. demosthenesii Lumbsch & Messuti, L. guderleyi Lumbsch & Messuti, L. pallidochlorina Nash, Ryan & Lumbsch, L. pseudachroa Lumbsch & Messuti, and L. ryanii Nash & Lumbsch, are described. Descriptions for L. carneolutescens and L. orizabana are provided. These overlooked species are new to the U.S.A.

Occurrence of arbuscular mycorrhizas and dark septate endophytes in pteridophytes from a patagonian rainforest, Argentina

Arbuscular mycorrhizas (AM) are one of the most widespread types of symbiotic associations. Pteridophytes occupy an important position in the evolution of vascular plants. However, their mycorrhizal state remains poorly understood. The aim of this work was to describe the general mycorrhizal status and the occurrence of dark septate endophytes (DSE) in the pteridophytic flora of a Valdivian temperate forest in Patagonia, Argentina. First, the roots of nine terrestrial species representing six families were examined, and this information was then compared with other surveys concerning the occurrence of AM in other pteridophytic species within the same Valdivian temperate forest. AM were recorded in 98.6% of the samples analyzed in this work and all of them corresponded to the Paris‐type morphology. DSEs were also present within the roots of all terrestrial species. A comparison to published results in other ferns and lycophytes that have been studied in this Valdivian temperate forest (161 sporophytes, 21 species and 10 families) was made. Clear differences in colonization patterns between eusporangiate/leptosporangiate and epiphytic/terrestrial species became evident and are discussed.

The species pair Pseudocyphellaria pilosella-piloselloides (lichenized Ascomycota: Lobariaceae ) is a single species

Fil: Messuti, Maria Ines. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina