Lichen systematics
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Systematics of the wood-inhabiting lichen genus Xylographa . Wood-dependent organisms, often called saproxylic or lignicolous organisms, have been a major focus on conservation in areas with...
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Cambridge Journals Online - The Lichenologist - Abstract - Phylogenetic position of the crustose Stereocaulon species

Cambridge Journals Online - The Lichenologist - Abstract - Phylogenetic position of the crustose Stereocaulon species | Lichen systematics | Scoop.it

Phylogenetic relationships of Stereocaulon with emphasis on the crustose taxa were studied based on nuclear ribosomal ITS1ITS2 and partial beta-tubulin sequences. The placement of four of the six crustose species currently included in the genus has previously been confirmed based on molecular data. It has, however, remained unresolved whether the crustose growth form is a plesiomorphic or apomorphic feature within Stereocaulon, due to contradictory placements of the crustose species in earlier studies. The aim of this study was to clarify the position of the crustose species by including additional data, especially of S. nivale and S. plicatile, which have not been included in previous analyses. The inclusion of S. plicatile in the genus is of particular interest as it is the only species in the genus with submurifrom to muriform ascospores. Altogether 37 specimens representing 31 species of the ingroup, including all the crustose Stereocaulon species, were incorporated in the analyses. Conventional, as well as direct optimization parsimony, maximum likelihood and Bayesian analyses were performed. The results show that the crustose species do not form a monophyletic entity and that the crustose growth form is a plesiomorphic feature within Stereocaulon. The crustose S. nivale and S. plicatile are nested within the genus and their inclusion in Stereocaulon is thereby confirmed. The nested position of S. plicatile indicates that the submuriform to muriform spore type has been gained independently within the genus. Here, S. plicatile is also reported for the first time from Scandinavia.

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Next-generation sequencing reveals sterile crustose lichen phylogeny

Next-generation sequencing reveals sterile crustose lichen phylogeny | Lichen systematics | Scoop.it

Next-generation sequencing reveals sterile crustose lichen phylogeny

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Pleistocene Speciation in North American Lichenized Fungi and the Impact of Alternative Species Circumscriptions and Rates of Molecular Evolution on Divergence Estimates

Pleistocene Speciation in North American Lichenized Fungi and the Impact of Alternative Species Circumscriptions and Rates of Molecular Evolution on Divergence Estimates | Lichen systematics | Scoop.it

AbstractPleistocene climatic fluctuations influenced patterns of genetic variation and promoted speciation across a wide range of species groups. Lichens are commonly found in habitats that were directly impacted by glacial cycles; however, the role of Pleistocene climate in driving speciation in most lichen symbionts remains unclear. This uncertainty is due in part to limitations in our ability to accurately recognize independently evolving lichen-forming fungal lineages and a lack of relevant fossil calibrations. Using a coalescent-based species tree approach, we estimated divergence times for two sister clades in the genus Xanthoparmelia(Parmeliaceae) restricted to western North America. We assessed the influence of two different species circumscription scenarios and various locus-specific rates of molecular evolution on divergence estimates. Species circumscriptions were validated using the program BP&P. although speciation was generally supported in both scenarios, divergence times differed between traditional species circumscriptions and those based on genetic data, with more recent estimates resulting from the former. Similarly, rates of evolution for different loci resulted in variable divergence time estimates. However, our results unambiguously indicate that diversification in the sampled Xanthoparmelia clades occurred during the Pleistocene. Our study highlights the potential impact of ambiguous species circumscriptions and uncertain rates of molecular evolution on estimating divergence times within a multilocus species tree framework.

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Insights into intrathalline genetic diversity of the cosmopolitan lichen symbiotic green alga Trebouxia decolorans Ahmadjian using microsatellite markers

Insights into intrathalline genetic diversity of the cosmopolitan lichen symbiotic green alga Trebouxia decolorans Ahmadjian using microsatellite markers | Lichen systematics | Scoop.it
Highlights •Microsatellites reveal high intrathalline algal diversity in two lichen-forming fungi (X. parietina, A. ciliaris).•High genetic differentiation among thalli suggests that algal diversity is generated de novo via mutation.•Thalli of Xanthoria parietina harbor more diverse algal pools, suggesting additional environmental uptake of photobionts.
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Molecular phylogenetics and taxonomy of Hypocenomyce

Molecular phylogenetics and taxonomy of Hypocenomyce | Lichen systematics | Scoop.it

We have addressed phylogenetic relationships and tested hypotheses about five presumed subgroups among 15 species of Hypocenomyce s.l. (including Pycnora) by use of nuclear (ITS, LSU) and mitochondrial (SSU) ribosomal DNA-regions. Bayesian, likelihood and parsimony phylogenetic analyses, of a dataset with broad Lecanoromycete taxon sampling, mostly support the five presumed subgroups, but two of these were found to be polyphyletic (the H. friesii-group and Pycnora). The seven supported Hypocenomyce s.l. clades belong in different genera, families, orders and even subclasses, and represent a remarkable example of morphological and ecological convergence. Based on our molecular phylogenetic results, we split Hypocenomyce into four genera placed in two subclasses: (1) Carbonicola gen. nov. (Carbonicolaceae fam. nov., Lecanorales, Lecanoromycetidae; including C. anthracophila comb. nov., C. foveata comb. nov., and C. myrmecina comb. nov.); (2) Fulgidea gen. nov. (Umbilicariaceae, Umbilicariales, Umbilicariomycetidae subcl. nov.; including F. oligospora comb. nov. and F. sierrae comb. nov.); (3) Hypocenomyce (Ophioparmaceae, Umbilicariales; including H. australis, H. scalaris, and H. tinderryensis; and (4) Xylopsora gen. nov. (Umbilicariaceae; including X. caradocensis comb. nov. and X. friesii comb. nov.). We split Pycnora into two genera: (1) Pycnora (Pycnoraceae fam. nov., Candelariales, "Candelariomycetidae"; including P. praestabilis, P. sorophora, and P. xanthococca); and (2) Toensbergia gen. nov. (Sporastatiaceae fam. nov., unknown order, Lecanoromycetidae; including T. leucococca comb. nov.). We place Hypocenomyce isidiosa in Xylographa (Trapeliaceae, Baeomycetales, Ostropomycetidae; X. isidiosa comb. nov.). We place the family Ophioparmaceae in the Umbilicariales. Our type studies have shown that the epithet “myrmecina” should replace “castaneocinerea”, and lectotypes are chosen for Lecidea friesii Ach., L. scalaris var. myrmecina Ach., Psora cladonioides var. albocervina Räsänen, and P. cladonioides var. castaneocinerea Räsänen. Elixia cretica is reported as new to North America (from Mexico) and Australia.

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Expanded taxon sampling disentangles evolutionary relationships and reveals a new family in Peltigerales (Lecanoromycetidae, Ascomycota)

Expanded taxon sampling disentangles evolutionary relationships and reveals a new family in Peltigerales (Lecanoromycetidae, Ascomycota) | Lichen systematics | Scoop.it

AbstractLichens that incorporate cyanobacterial symbionts (cyanolichens) are an ecologically key group of species used as biomonitors at all latitudes. Cyanolichen evolution is however based on intense studies of few keystone species and the bulk of species diversity, especially of small species in cold climates, has yet to be accounted for in phylogenetic studies. We assembled an expanded data set including members of all nine currently accepted Peltigeralean families as well as hitherto undersampled representatives of small, radially symmetrical, placodioid cyanolichen genera from the Northern and Southern Hemispheres. Bayesian and maximum likelihood consensus trees from our multilocus analyses (nuSSU, nuLSU and mtSSU) recovered the genera Koerberia, Vestergrenopsis and Steinera as a new, fully supported, family-level clade within the Peltigerales. This clade is further supported by a posteriori morphological analysis and we describe it here as the new family Koerberiaceae. The recently described and physiognomically similar genus Steineropsis, by contrast, is recovered as sister to Protopannaria in the Pannariaceae (Collematineae). Previous analyses have recovered strong monophyletic groups around Pannariaceae, Lobariaceae and Peltigeraceae. We discuss in detail the phylogenetic relationships of all these taxa, provide a pan-Peltigeralean overview of phenotypic characteristics and illustrate all major ascus apical structures. Our topology provides strong backbone support for the sister relationship of Peltigerineae to Collematineae as well as for most currently recognized families of the Peltigerales. The following new combinations are made: Steinera symptychia(Tuck.) T. Sprib. & Muggia, and Vestergrenopsis sonomensis (Tuck.) T. Sprib. & Muggia

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A radical shift in the taxonomy of Lepraria s.l.: Molecular and morphological studies shed new light on the evolution of asexuality and lichen growth form diversification

A radical shift in the taxonomy of Lepraria s.l.: Molecular and morphological studies shed new light on the evolution of asexuality and lichen growth form diversification | Lichen systematics | Scoop.it

Abstract

A combination of molecular phylogenetic analyses of ITS and mtSSU sequences, morphological and chemical analyses were used to investigate the lineages nominally included in the sterile lichen genus Lepraria. A core group (Lepraria s. str.) was resolved as sister to Stereocaulon. Species producing the secondary compounds argopsin, pannarin and usnic acid were found to belong to other lineages of lichen-forming ascomycetes. Study of Leprocaulon revealed that all species, except the type, likely represent members of Lepraria s. str. that have evolved a fruticose growth form. The correct name for the type species of Leprocaulon is shown to be L. quisquiliare, not L. microscopicum, and the genus is redefined to include several species previously placed in Lepraria. Leprocaulon quisquiliare is also shown to comprise two morphologically convergent species. The name is lectotypified and epitypified on material from the type region (Germany) and its application restricted to Old World populations. New World populations of L. quisquiliare are described as L. americanum. Leprocaulon, in its revised sense, is recognized in a new family (Leprocaulaceae) and order (Leprocaulales) sister to the Caliciales and including the genus Halecania. A new genus of Pilocarpaceae, Nelsenium, is introduced to accommodate Lepraria usnica. The status of Lepraria ecorticata is discussed in the context of usnic acid-producing Lecanora species. These nomenclatural novelties are proposed: (i) transfers from Leprocaulon to Lepraria: Lepraria albicans comb. nov., L. arbuscula comb. nov., L. congestum comb. nov., L. gracilescens comb. nov., L. pseudoarbuscula comb. nov., L. subalbicans comb. nov., L. tenellum comb. nov.; (ii) transfers from Lepraria to Leprocaulon: Leprocaulon adhaerens comb. nov., L. coriense, L. santamonicae comb. nov., L. terricola comb. nov. and L. textum comb. nov.; (iii) new taxa: Leprocaulales ord. nov., Leprocaulaceae fam. nov., Nelsenium gen. nov., Leprocaulon americanum sp. nov. and L. knudsenii.sp. nov.

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A molecular perspective on generic concepts in the Hypotrachyna clade (Parmeliaceae, Ascomycota)

A molecular perspective on generic concepts in the Hypotrachyna clade (Parmeliaceae, Ascomycota) | Lichen systematics | Scoop.it

Abstract

Recently, molecular phylogenetic studies have revolutionized the generic concepts in Parmeliaceae and in lichen forming fungi in general. In the present study, the generic delimitation in the Hypotrachyna clade is revised using a molecular phylogeny of nuclear ITS, LSU and mitochondrial SSU rDNA sequences of 88 hypotrachynoid taxa. Morphological and chemical features are also revised in each group. 118 sequences are newly generated for this study. Our phylogenetic analyses show the polyphyly of Hypotrachyna as currently circumscribed which falls into four well-supported and one unsupported clade. Cetrariastrum, Everniastrum and Parmelinopsis are nested within Hypotrachyna s. lat., Parmelinopsis being also polyphyletic and nested in one of the Hypotrachyna clades. Cetrariastrum is monophyletic but clustered within Everniastrum. Two alternative hypotheses tests significantly rejected the monophyly of these three genera. As a consequence, the genera Cetrariastrum, Everniastrum, and Parmelinopsis are reduced to synonymy with Hypotrachyna. Furthermore, we here propose an alternative classification to recognize the well-supported clades at subgeneric level and leave the remaining species unclassified within the genus. Five new subgenera are proposed: Hypotrachyna subgen. Cetrariastrum, Hypotrachyna subgen. Everniastrum, Hypotrachyna subgen. Longilobae, Hypotrachyna subgen. Parmelinopsis, and Hypotrachyna subgen. Sinuosae. Forty-nine new combinations are proposed.

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Cardinal characters on a slippery slope – A re-evaluation of phylogeny, character evolution, and evolutionary rates in the jelly lichens (Collemataceae s. str)

Cardinal characters on a slippery slope – A re-evaluation of phylogeny, character evolution, and evolutionary rates in the jelly lichens (Collemataceae s. str) | Lichen systematics | Scoop.it

Highlights

 -The phylogeny of Collemataceae is inferred from a dataset of 4 genes and 70 species.

-Collemataceae comprises eleven well-supported monophyletic groups.

-The evolution of 3 morphological and 1 ecological traits is studied by ancestral state reconstruction.

-A mainly wet-tropical humid-temperate lineage exhibits accelerated evolutionary rate.

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Molecular phylogenetic studies on tropical species of Lecanora sensu stricto (Lecanoraceae, Ascomycota)

Abstract

The genus Lecanora is one of the largest genera of crustose lichens and includes a number of distinct clades. Lecanora sensu stricto is characterized by oxalate crystals in the apothecial margin and the presence of atranorin and/or usnic acid. Currently, the phylogenetic relationships of tropical taxa in Lecanora s.str. are poorly understood. To address the phylogeny of tropical species and to test whether certain characters found predominantly in tropical taxa (usnic acid and dark hypothecium) have evolved several times or not we assembled a data set including two loci (ITS, mtSSU rDNA) of 35 species. Species that contain usnic acid do not form a monophyletic group, suggesting that the presence of this metabolite is of restricted taxonomic importance above the species level. Also species with a dark hypothecium do not form a monophyletic group. Monophyly of both groups was rejected using alternative topology tests. These results suggest that usnic acid and a dark hypothecium are adaptations of tropical Lecanora spp. that evolved several times independently within this clade oflichenized fungi. The placements of the aspicilioid L. subimmersa and the almost biatorine L. flavo-pallida in Lecanora s.str. are supported by our study. Three of the included species, viz. L. achroa, L. caesiorubella, and L. helva were shown to be not monophyletic.

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Exploring symbiont management in lichens -

Exploring symbiont management in lichens - | Lichen systematics | Scoop.it
Abstract

Lichens are unique among fungal symbioses in that their mycelial structures are compact and exposed to the light as thallus structures. The myriad intersections of unique fungal species with photosynthetic partner organisms (green algae in 90% of lichens) produce a wide variety of diverse shapes and colours of the fully synthesized lichen thallus when growing in nature. This characteristic complex morphology is, however, not achieved in the fungal axenic state. Even under ideal environmental conditions, the lichen life cycle faces considerable odds: first, meiotic spores are only produced on well-established thalli and often only after achieving considerable age in a stable environment, and second, even then in vivo resynthesis requires the presence of compatible algal strains where fungal spores germinate. Many lichen species have evolved a way around the resynthesis bottleneck by producing asexual propagules for joint propagation of symbionts. These different dispersal strategies ostensibly shape the population genetic structure of lichen symbioses, but the relative contributions of vertical (joint) and horizontal (independent) symbiont transmission have long eluded lichen evolutionary biologists. In this issue of Molecular Ecology, Dal Grande et al. (2012) close in on this question with the lung lichen, Lobaria pulmonaria, a flagship species in the conservation of old growth forests. By capitalizing on available microsatellite markers for both fungal and algal symbionts, they show that while vertical transmission is the predominant mode of reproduction, horizontal transmission is demonstrable and actively shapes population genetic structure. The resulting mixed propagation system is a highly successful balance of safe recruitment of symbiotic clones and endless possibilities for fungal recombination and symbiont shuffling.

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Taxonomy of the genus Myrionora, with a second species from South Americ

Abstract

A taxonomic and biogeographic overview of the genus Myrionora is provided. Two species are recognized, M. albidula (Willey) R. C. Harris and M. pseudocyphellariae (Etayo) S. Ekman & Palice comb. nov. The genus is characterized by polysporous asci, the presence of crystals in the hymenium and proper exciple that partly consist of lobaric acid, and a photobiont with large cells (mostly in the range 12-20 mu m). Myrionora albidula is currently known from Germany, Norway, Sweden, the Russian Federation (Altayskiy Kray, Chelyabinskaya Oblast', Khabarovskiy Kray and Zabaykal'skiy Kray), and the United States (Alaska, Connecticut, Maine and Massachusetts). It inhabits bark of deciduous trees and shrubs and conifers over a wide range of latitudes. Myrionora pseudocyphellariae is known from Chile and Ecuador, where it has been encountered on lichens and decaying bark. Based on morphological characteristics, we conclude that Myrionora belongs in the Ramalinaceae.

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A single macrolichen constitutes hundreds of unrecognized species

The number of Fungi is estimated at between 1.5 and 3 million. Lichenized species are thought to make up a comparatively small portion of this figure, with unrecognized species richness hidden among little-studied, tropical microlichens. Recent findings, however, suggest that some macrolichens contain a large number of unrecognized taxa, increasing known species richness by an order of magnitude or more. Here we report the existence of at least 126 species in what until recently was believed to be a single taxon: the basidiolichen fungus Dictyonema glabratum, also known as Cora pavonia. Notably, these species are not cryptic but morphologically distinct. A predictive model suggests an even larger number, with more than 400 species. These results call into question species concepts in presumably well-known macrolichens and demonstrate the need for accurately documenting such species richness, given the importance of these lichens in endangered ecosystems such as paramos and the alarming potential for species losses throughout the tropics.


Via Håvard Kauserud
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Leavitt's Lichens

Steve Leavitt studies one of the world's most common but overlooked symbiotic systems, lichens. Using DNA analysis he explores the hidden world of lichen evo...

Via Jared Berent
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Lepidostromatales, a new order of lichenized fungi (Basidiomycota, Agaricomycetes), with two new genera, Ertzia and Sulzbacheromyces, and one new species, Lepidostroma winklerianum

Lepidostromatales, a new order of lichenized fungi (Basidiomycota, Agaricomycetes), with two new genera, Ertzia and Sulzbacheromyces, and one new species, Lepidostroma winklerianum | Lichen systematics | Scoop.it

Abstract

We present a revised molecular phylogeny of higher Basidiomycota focusing on Lepidostromataceae based on the large subunit (28S) of the nuclear ribosomal rDNA (nuLSU), with additionl data from the translation elongation factor 1 alpha 1 (TEF1) and the RNA polymerase II second largest subunit (RPB2) genes. Our results suggest that Lepidostromataceae is best recognized in a separate order, Lepidostromatales ordo novum, within subclass Agaricomycetidae. Furthermore, the internal topology of Lepidostromataceae, correlating with thallus features, indicates that three genera, instead of a single genus, should be recognized. We therefore introduce the genera Ertzia genus novum and Sulzbacheromyces genus novum for Lepidostroma akagerae and L. caatingae, respectively. In addition, the new species L. winklerianum spec. nova is described for Mexican material previously identified as L. calocerum. The photobionts of Sulzbacheromyces and Lepidostroma were identified using molecular data of the large subunit of the ribulose 1,5-bisphosphate carboxylase/oxygenase (rbcL) gene, revealing a possibly undescribed genus in Trebouxiophyceae and the first report of lichenization for the genus Bracteacoccus in Chlorophyceae.

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Dating the Diversification of the Major Lineages of Ascomycota (Fungi)

Dating the Diversification of the Major Lineages of Ascomycota (Fungi) | Lichen systematics | Scoop.it
AbstractEstablishing the dates for the origin and main diversification events in the phylogeny of Ascomycota is among the most crucial remaining goals in understanding the evolution of Fungi. There have been several analyses of divergence times in the fungal tree of life in the last two decades, but most have yielded contrasting results for the origin of the major lineages. Moreover, very few studies have provided temporal estimates for a large set of clades within Ascomycota. We performed molecular dating to estimate the divergence times of most of the major groups of Ascomycota. To account for paleontological uncertainty, we included alternative fossil constraints as different scenarios to enable a discussion of the effect of selection of fossils. We used data from 6 molecular markers and 121 extant taxa within Ascomycota. Our various ‘relaxed clock’ scenarios suggest that the origin and diversification of the Pezizomycotina occurred in the Cambrian. The main lineages of lichen–forming Ascomycota originated at least as early as the Carboniferous, with successive radiations in the Jurassic and Cretaceous generating the diversity of the main modern groups. Our study provides new information about the timing of the main diversification events in Ascomycota, including estimates for classes, orders and families of both lichenized and non–lichenized Ascomycota, many of which had not been previously dated.
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Testing the use of ITS rDNA and protein-coding genes in the generic and species delimitation of the lichen genus Usnea (Parmeliaceae, Ascomycota)

Testing the use of ITS rDNA and protein-coding genes in the generic and species delimitation of the lichen genus Usnea (Parmeliaceae, Ascomycota) | Lichen systematics | Scoop.it

Highlights

•The genus Usnea is subdivided into at least four highly-supported clades.•Character homoplasy hinders the description of new generic subdivisions.•Methods of alignment of ITS rDNA significantly influence the phylogenetic trees.•Although less variable, protein-coding genes give a better phylogenetic resolution than ITS rDNA.

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Local representation of global diversity in a cosmopolitan lichen-forming fungal species complex (Rhizoplaca, Ascomycota)

Local representation of global diversity in a cosmopolitan lichen-forming fungal species complex (Rhizoplaca, Ascomycota) | Lichen systematics | Scoop.it

Abstract

 

Aim - The relative importance of long-distance dispersal versus vicariance in determining the distribution of lichen-forming fungi remains unresolved. Here, we examined diversity and distributions in a cosmopolitan lichen-forming fungal species complex, Rhizoplaca melanophthalma sensu lato (Ascomycota), across a broad, intercontinental geographical distribution. We sought to determine the temporal context of diversification and the impacts of past climatic fluctuations on demographic dynamics within this group.

 

Location - Antarctica, Asia, Europe, North America and South America.

 

Methods - We obtained molecular sequence data from a total of 240 specimens of R. melanophthalma s.l. collected across five continents. We assessed the monophyly of candidate species using individual gene trees and a tree from a seven-locus concatenated data set. Divergence times and relationships among candidate species were evaluated using a multilocus coalescent-based species tree approach. Speciation probabilities were estimated using the coalescent-based species delimitation program bpp. We also calculated statistics on molecular diversity and population demographics for independent lineages.

 

Main conclusions - Our analyses of R. melanophthalma s.l. collected from five continents supported the presence of six species-level lineages within this complex. Based on current sampling, two of these lineages were found to have broad intercontinental distributions, while the other four were limited to western North America. Of the six lineages, five were found on a single mountain in the western USA and the sixth occurred no more than 200 km away from this mountain. Our estimates of divergence times suggest that Pleistocene glacial cycles played an important role in species diversification within this group. At least three lineages show evidence of recent or ongoing population expansion.

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Pleistocene expansion of the bipolar lichen Cetraria aculeata into the Southern hemisphere

Pleistocene expansion of the bipolar lichen Cetraria aculeata into the Southern hemisphere | Lichen systematics | Scoop.it
Abstract

Many boreal and polar lichens occupy bipolar distributional ranges that frequently extend into high mountains at lower latitudes. Although such disjunctions are more common among lichens than in other groups of organisms, the geographic origin of bipolar lichen taxa, and the way and time frame in which they colonized their ranges have not been studied in detail. We used the predominantly vegetative, widespread lichen Cetraria aculeata as a model species. We surveyed the origin and history of its bipolar pattern using population genetics, phylogenetic and genealogical reconstruction methods. Cetraria aculeata originated in the Northern Hemisphere and dispersed southwards during the Pleistocene. The genetic signal suggests a Pleistocene dispersive burst in which a population size expansion concurred with the acquisition of a South-American range that culminated in the colonization of the Antarctic.

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Genetic diversity and species delimitation of the zeorin-containing red-fruited Cladonia species (lichenized Ascomycota) assessed with ITS rDNA and beta-tubulin data

Genetic diversity and species delimitation of the zeorin-containing red-fruited Cladonia species (lichenized Ascomycota) assessed with ITS rDNA and beta-tubulin data | Lichen systematics | Scoop.it

Abstract

Zeorin-containing red-fruited Cladonia species, the so-called C. coccifera group, are widespread terrestrial lichens which share most of their secondary substances but differ morphologically. The main objective of this study was to explore whether the current delimitation of these species is supported bymolecular data. A total of 52 European and North American specimens of C. coccifera, C. deformis, C. diversa, and C. pleurota were examined. The internal transcribed spacer regions of the nuclear ribosomal DNA and the beta-tubulin gene loci were sequenced for phylogenetic analyses. Traditional morphological species circumscriptions in zeorin-containing members of the C. coccifera group are not supported by molecular data. Cladonia coccifera, C. deformis, and C. pleurota were recovered as polyphyletic in both gene topologies; C. diversa formed a lineage in the ITS phylogeny but this was not statistically supported. We detected chemical patterns of the presence/absence of porphyrilic and/or isousnic acid which may help to characterize two lineages. Our results also show incongruence between the two molecular markers studied. Therefore, we focused on possible explanations of this phenomenon. Five major evolutionary mechanisms can potentially result in phylogenetic discordance between genes: presence of pseudogenes, horizontal gene transfer, gene paralogy, incomplete lineage sorting, and hybridization. These mechanisms are briefly discussed. We consider incomplete lineage sorting and/or hybridization to best explain the incongruence.

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Journey from the West: Did tropical Graphidaceae (lichenized Ascomycota: Ostropales) evolve from a saxicolous ancestor along the American Pacific coast?

Journey from the West: Did tropical Graphidaceae (lichenized Ascomycota: Ostropales) evolve from a saxicolous ancestor along the American Pacific coast? | Lichen systematics | Scoop.it

ABSTRACT

• Premise of the study: This study elucidates the phylogenetic position of a unique taxon of Graphidaceae occurring on rock in coastal desert areas, assessing its importance for our understanding of the evolution of the largest family of tropical lichenized fungi.

• Methods: We used maximum likelihood and Bayesian approaches to reconstruct a three-gene phylogeny of Graphidaceae and a Bayesian molecular clock approach to estimate divergence dates for major clades, as well as Bayesian ancestral ecogeography state analysis.

• Key results: The new genus Redonographa represents a new subfamily, Redonographoideae, sister to subfamily Graphidoideae. Redonographa is exclusively saxicolous and restricted to the American Pacific coast from California to central Chile, including Galapagos. It contains four species:Redonographa chilensis comb. nov., R. saxiseda comb. nov., R. saxorumcomb. nov., and R. galapagoensis sp. nov. The genus Gymnographopsis, with a similar ecogeography but differing in excipular carbonization and chemistry, is also included in Redonographoideae, with the species G. chilena from Chile and G. latispora from South Africa. Molecular clock analysis indicates that Redonographoideae diverged from Graphidoideae about 132 million years ago (Ma) in the Early Cretaceous.

• Conclusions: The divergence date for subfamilies Redonographoideae and Graphidoideae coincides with the early breakup of Gondwana and ancient origin of the Atacama Desert. However, the common ancestor of Redonographoideae plus Graphidoideae was reconstructed to be tropical-epiphytic. Thus, even if Redonographoideae is subtropical-saxicolous, the hypothesis that Graphidoideae evolved from a subtropical-saxicolous ancestor is not supported.

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Multilocus phylogeny of the lichen-forming fungal genus Melanohalea (Parmeliaceae, Ascomycota): Insights on diversity, distributions, and a comparison of species tree and concatenated topologies

Multilocus phylogeny of the lichen-forming fungal genus Melanohalea (Parmeliaceae, Ascomycota): Insights on diversity, distributions, and a comparison of species tree and concatenated topologies | Lichen systematics | Scoop.it
Highlights

► We assess diversity and biogeographic patterns in the lichenized genus Melanohalea. ► The majority of classical Melanohalea species were supported by molecular data. ► We identify previously unrecognized lineages within six traditional species. ► Contrasting patterns of intercontinental and geographically restricted distributions. ► A coalescent-based multilocus species tree is presented for Melanohalea.

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Scooped by Mika Bendiksby
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Phylogenetic study of Diploschistes (lichen-forming Ascomycota: Ostropales: Graphidaceae), based on morphological, chemical, and molecular data

Phylogenetic study of Diploschistes (lichen-forming Ascomycota: Ostropales: Graphidaceae), based on morphological, chemical, and molecular data | Lichen systematics | Scoop.it

Abstract

The genus Diploschistes includes crustose lichen-forming fungi with a carbonized proper excipulum with lateral paraphyses, and a chemistry dominated by orcinol depsides. However, the taxon D. ocellatus lacks these excipular characters and has beta-orcinol depsidones, raising doubts about its inclusion within this genus. Using a two-locus dataset (mtSSU, nuLSU), our phylogenetic analyses confirm the classification of D. ocellatus within Diploschistes. Three different groups have been recognized within this genus, based on ascomatal morphology: Actinostomus (perithecioid), Scruposus (urceolate), and Ocellatus (lecanoroid). These groups have been widely used in monographic studies and keys, but their taxonomic value has not been confirmed yet. Here we inferred phylogenetic relationships within Diploschistes, with a special emphasis on the D. scruposus complex, using a combined dataset consisting of morphological, chemical, nrITS, and mtSSU data in order to determine if these species groups and phenotypically based species delimitations were monophyletic. Based on our results, a new subgeneric treatment for Diploschistes is proposed, and the taxonomic value of fruiting body types is confirmed. The clade corresponding to D. ocellatus consists of two well-supported subclades, one of them grouping specimens without ascomata, having only pycnidia. It is also remarkable that the clade containing specimens of D. diacapsis subsp. neutrophilits appears distantly related to the clade containing all other accessions of D. diacczpsis. Our analysis revealed that for some taxa, such as D. scruposus and D. interpediens, molecular variability did not correlate with either morphological or chemical diversity

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Phylogeny and character evolution in the jelly fungi (Tremellomycetes, Basidiomycota, Fungi)

Phylogeny and character evolution in the jelly fungi (Tremellomycetes, Basidiomycota, Fungi) | Lichen systematics | Scoop.it
Highlights

► The lichenicolous taxa in the Tremellomycetes clearly belong within this group. ► Basidium habit and basidium septation are homoplastic in theTremellomycetes. ► Changes in the basidium habit are consistent with a punctuated mode of evolution. ► Weak evidence suggests graduational evolution in the basidium septation.

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