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The manna lichens, a group of vagrant species with subfruticose and subfoliose thalli in the genus Circinaria Link, have received attention for millennia. Here, a new manna lichen species, Circinaria nimisii sp. nov. (Megasporaceae), is described and illustrated. This vagrant lichen is found on Mount Olympus in Greece and is the fourth known manna lichen in Europe. The new taxon is characterized by its subfruticose, densely-branched thallus with a muddy, earthy colour, whitish pseudocyphellae on tips of branches, mature apothecia distinctly adnate to stipitate, and paraplectenchymatous cortex tissue. Molecular sequence data from the standard barcoding marker (nrITS) also corroborate the distinction of this species from closely related congeners. Finally, Agrestia zerovii, previously known only from its type locality in Ukraine, is proposed as a new synonym of Circinaria hispida.
Species of lichen-forming fungi (LFF) display an array of geographical distribution patterns. Among the broadly distributed lichen-forming fungal species, the degree of reproductive isolation and genetic substructure among populations varies widely, in some cases masking unrecognized diversity or meaningful biogeographical patterns. Lecidea atrobrunnea (Raymond ex Lam. & DC.) Schaer. s. lat. (Lecideaceae) is a widespread species complex that has been studied for over two centuries since its initial description. The diversity of the L. atrobrunnea group is highest in western North America, where a dizzying array of morphologies and chemistry can occur at local scales. Here we investigate whether the assumed cosmopolitan distribution of L. atrobrunnea s. lat. is an artifact of taxonomic limitations and masks biogeographical patterns in this species complex. To address these questions, we compiled sequence data from the standard fungal barcoding marker (ITS) for over 100 specimens within this complex, in addition to genome-scale data from a subset of these representing over 1600 single-copy nuclear genes spanning over 3 Mb of the genome. Our study corroborates the perspective that the morphologically and chemically variable Lecidea atrobrunnea group reflects a complex of distinct species-level lineages, with 42–83 candidate species inferred from the ITS region and high levels of diversity inferred from a subset of specimens using genome-scale data. However, both phenotype- and molecular-based species boundaries remained unsettled, with the most common nominal taxa recovered as highly polyphyletic and with conflict among different molecular species delimitation approaches. Our study also highlights the potential for geographically restricted species, with fascinating biogeographical patterns, challenging, in part, the assumed cosmopolitan distribution of L. atrobrunnea s. lat. This study provides valuable direction for future research that will be crucial in understanding diversification and establishing a robust taxonomy for this well-known species complex.
Lichens of the Ramalina siliquosa complex dominate seashore cliffs in Europe and South-East Asia, but their taxonomy has been vigorously debated for over a century. On many cliffs, they exhibit a bewildering zonation of chemotypes that resembles the classic zonation of organisms that occupy the littoral zone below. Do the chemotypes represent separate species, or infraspecific variation? To better understand the systematics of this group, sequences from four genetic loci (ITS, IGS, RPB1 and RPB2) were obtained for 59 samples from Denmark, France, Iceland, Norway, UK, Japan and Korea, including all major chemotypes. Maximum likelihood analysis of these sequences, together with sequences from 36 other Ramalina species, reveals that the complex comprises two distinct phylogenetic lineages, each including multiple chemotypes. These two putative species-level lineages correspond to the currently accepted taxa R. cuspidata and R. siliquosa. There is no evidence that these two taxa are phylogenetic sister species. Consequently, the explanation of this chemotype complex as an example of ‘sibling speciation’ is rejected. Specimens traditionally called ‘R. siliquosa’ from South-East Asia form a third clade, identified here as R. semicuspidata, with an additional, divaricatic acid chemotype. Other results include a robustly supported clade of Ramalina species that produce medullary depsides and depsidones; this clade includes another well-supported clade of south-eastern United States coastal plain and tropical Ramalina species. By contrast, large, strap-shaped Ramalina species that lack medullary depsides and depsidones occur in separate lineages. In addition, close relationships between the following groups of species are indicated: R. farinacea with R. subfarinacea; R. fraxinea with R. leptocarpha, R. menziesii and R. subleptocarpha; R. sinensis with R. unifolia. Furthermore, a new, variolaric acid-only chemotype is reported for R. farinacea, and a new, acid-deficient chemotype is reported for a more broadly circumscribed R. culbersoniorum.
Species richness is not evenly distributed across the tree of life and a limited number of lineages comprise an extraordinarily large number of species. In lichen-forming fungi, only two genera are known to be ‘ultradiverse’ (>500 species), with the most diverse genus, Xanthoparmelia, consisting of c. 820 species. While Australia and South Africa are known as current centres of diversity for Xanthoparmelia, it is not well known when and where this massive diversity arose. To better understand the geographical and temporal context of diversification in this diverse genus, we sampled 191 Xanthoparmelia specimens representing c. 124 species/species-level lineages from populations worldwide. From these specimens, we generated a multi-locus sequence data set using Sanger and high-throughput sequencing to reconstruct evolutionary relationships in Xanthoparmelia, estimate divergence times and reconstruct biogeographical histories in a maximum likelihood and Bayesian framework. This study corroborated the phylogenetic placement of several morphologically or chemically diverse taxa within Xanthoparmelia, such as Almbornia, Chondropsis, Karoowia, Namakwa, Neofuscelia, Omphalodiella, Paraparmelia, Placoparmelia and Xanthomaculina, in addition to improved phylogenetic resolution and reconstruction of previously unsampled lineages within Xanthoparmelia. Our data indicate that Xanthoparmelia most likely originated in Africa during the early Miocene, coinciding with global aridification and development of open habitats. Reconstructed biogeographical histories of Xanthoparmelia reveal diversification restricted to continents with infrequent intercontinental exchange by long-distance dispersal. While likely mechanisms by which Xanthoparmelia obtained strikingly high levels of species richness in Australia and South Africa remain uncertain, this study provides a framework for ongoing research into diverse lineages of lichen-forming fungi. Finally, our study highlights a novel approach for generating locus-specific molecular sequence data sets from high throughput metagenomic reads.
Macro-morphological features traditionally used to segregate genera in Parmeliaceae have been shown to be highly plastic, placing limits on their taxonomic value. Here we aim to elucidate the evolutionary relationships of the genera Relicina and Relicinopsis and reassess the phenotypic features traditionally used to separate these genera. To this end, we gathered ribosomal DNA sequences of ITS, nuLSU and mtSSU and analyzed them in a phylogenetic framework. Relicina was recovered as paraphyletic, with Relicinopsis nested within, and three different clades were identified within Relicina. Alternative hypothesis tests significantly rejected the monophyly of Relicina. Our results indicate that the presence or absence of bulbate cilia is of limited taxonomic value in this clade. Based on differences in conidia, however, we propose to accept Relicinopsis as a subgenus within Relicina as Relicina subgen. Relicinopsis (Elix & Verdon) Kirika, Divakar & Lumbsch. It is proposed that five new combinations of species previously classified in Relicinopsis be placed in Relicina.
Western North America is the global centre of diversity for Letharia, a distinctive and cryptically diverse genus of lichenized fungi belonging to the Parmeliaceae. The genus is characterized by a shrubby, fruticose habit and presence of vulpinic acid. Previous studies using multiple fungal nuclear loci revealed the existence of two distinct species-level lineages within the traditional concept of L. vulpina and four such lineages within L. columbiana. Here we use molecular sequence data in an attempt to settle long-standing taxonomic issues in the genus. Our results confirm the widespread existence within L. vulpina s. lat. of two distinct species-level groups, each forming a mutually exclusive partnership with a separate algal clade within Trebouxia jamesii s. lat. Accordingly, we formally describe the segregate species L. lupina sp. nov. Our results also support the evolutionary independence of four candidate species previously circumscribed from L. columbiana s. lat. One of these lineages, L. ‘gracilis’, has already received species recognition as L. gracilis, while a second, L. ‘lucida’, is epitypified here against L. columbiana s. str. Based on results from species delimitation analyses under the multispecies coalescent model, the two remaining lineages, L. ‘barbata’ and L. ‘rugosa’, also warrant formal taxonomic recognition; however, we refrain from describing these species pending additional studies of diagnostic characters, ecological preference, and distributions.
The phylogenetic position of the genus Pseudoparmelia was addressed using molecular data from five loci (mtSSU, nuLSU, ITS, Mcm7, RPB1), generated from three species and aligned with sequences from 293 samples representing all major clades of Parmeliaceae. Pseudoparmelia species form a well-supported monophyletic group that is the sister group of a clade consisting of the genera Relicina and Relicinopsis. These three genera share a thallus with a pored epicortex, isolichenan as cell wall polysaccharide, and relatively small ascospores. Morphological and chemical characters that distinguish Pseudoparmelia from the closely related Relicina and Relicinopsis are discussed. To further elucidate the relationships of these three genera, we assembled a second dataset including 15 additional samples of Relicina and Relicinopsis using three loci (mtSSU, nuLSU, ITS). All three genera are monophyletic but monophyly of Relicina lacks support and, in the mtSSU single locus tree, the genus is paraphyletic with Relicinopsis nested within. Additional studies including more Relicina species are necessary to test delimitation of the genera Relicina and Relicinopsis.
Previous studies have identified a close relationship between the monospecific Masonhalea richardsonii and Tuckermannopsis inermis. However, formal taxonomic changes were postponed until existing sequence data could be confirmed. Here we validate these data and discuss the transfer of T. inermis to Masonhalea (made by Lumbsch et al. in Thell & Moberg 2011), consider the morphological, anatomical and biogeographic similarities and differences between these two taxa. The two Masonhalea species both produce lateral apothecia, marginal pycnidia, a layer of cortical tissue beneath the pycnidial wall and bacillariform conidia.
The new species Oropogon evernicus Essl. & S. Leavitt and O. protocetraricus S. Leavitt & Essl. are described from montane regions of Central America, further increasing the diversity of this genus in the New World. Oropogon evernicus is separated from O. americanus by the presence of medullary tissue directly beneath the pseudocyphellae, while O. protocetraricus is separated from O. caespitosus by the presence of protocetraric acid. The segregation of both species is confirmed by molecular sequence data (nuclear ITS, nuLSU, and β-tubulin). Both species appear to have split from their most recent common ancestor during the Miocene, supporting Miocene-dominated diversification of neotropical Oropogon species found in Central America.
The relationship of Aspicilia uxoris within Megasporaceae is assessed within a phylogenetic context. ‘Aspicilia’ uxoris and other related species are recovered as sister to the genus Lobothallia s. str. and described here as a new genus. Teuvoa (Ascomycota, Megasporaceae) is erected based on nuclear ITS and LSU sequence data and morphological characters. In addition to Teuvoa uxoris, a second species, T. junipericola, is added to the new genus based on material collected from North America. Teuvoa junipericola, T. uxoris and T. tibetica form a group with 8-spored asci, absence of extrolites, rather short-sized conidia and ascospores, lack of a subhypothecial algal layer, and different substratum preferences (on organic substratum) with a sister relationship to genus Lobothallia s. lat. (Aspicilia subgenus Pachyothallia Clauzade & C. Roux). Based on spore measurements of the holotypes, Lecanora ferganensis Tomin from central Asia (Kyrgyzstan, Tajikistan and Uzbekistan), Lecanora atrodiscata Gintovt, from Tajikistan and Lecanora takyroides Dzhur. from Turkmenistan are new synonyms to T. uxoris. A lectotype for Lecanora ferganensis is designated, expanding the known distribution of T. uxoris from Algeria, Morocco and Spain, into Central Asia.