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Chicago Ridge, IL, United States

Dal-Forno M.,George Mason University | Lawrey J.D.,George Mason University | Sikaroodi M.,George Mason University | Bhattarai S.,George Mason University | And 3 more authors.
Fungal Biology | Year: 2013

Phylogenetic studies indicate that the basidiolichen genus Dictyonema s.lat., often thought to represent only a single genus with few species, includes several well-supported genus-level clades, all of which form associations with a unique lineage of obligately lichenized cyanobacteria (Rhizonema). In an attempt to elucidate the evolution and genus- and species-level diversification in Dictyonema s.lat., we generated 68 new sequences of the nuclear large subunit rDNA (nuLSU), the internal transcribed spacer (ITS), and the RNA polymerase II subunit (RPB2), for 29 species-level lineages representing all major clades of Dictyonema s.lat. and most of the species currently known. The multilocus phylogeny obtained via maximum likelihood and Bayesian approaches indicates the presence of five genus-level groups: a basal clade, Cyphellostereum, that is sister to the rest of the species, a paraphyletic grade representing Dictyonema s.str., and three clades representing the genera Acantholichen, Cora, and Corella. To determine the evolutionary transformations of the lichenized thallus in the group, ancestral character state reconstruction was done using six characters (lichenisation, thallus type, cortex type, hyphal sheath and haustorial type, photobiont morphology, and basidiocarp type). Our analysis indicates a progressive development of the lichenized thallus from loosely organized filamentous crusts with separate, cyphelloid basidiocarps in Cyphellostereum, to filamentous crusts with derived hyphal sheath and cyphelloid-stereoid basidiocarps partially incorporated into the lichen thallus in Dictyonema, to squamulose-foliose thalli with corticioid basidiocarps entirely supported by the lichen thallus in Cora. These results indicate a remarkable evolutionary integration of lichenized and reproductive tissues in Dictyonema s.lat., supporting the hypothesis that, at least in this case, lichenized thalli may have evolved from reproductive structures in their nonlichenized ancestors. © 2013 The British Mycological Society. Source

Yanez A.,Biodiversity Assessment | Yanez A.,Central University of Ecuador | Dal-Forno M.,George Mason University | Bungartz F.,Biodiversity Assessment | And 2 more authors.
Fungal Diversity | Year: 2012

As part of an ongoing comprehensive inventory of Galapagos lichens, a first assessment of the morphology and anatomy of basidiolichens from the archipelago is presented here. It is the basis for further studies of the taxonomy, ecology and biogeography of this poorly known group of lichens. Four genera, all in Hygrophoraceae, can be distinguished: Acantholichen, Cora, Cyphellostereum and Dictyonema. Both Acantholichen and Cora are characterized by chroococcoid cyanobionts and a heteromerous thallus with a distinct upper cortex and photobiont layer. The monotypic Acantholichen pannarioides is entirely composed of small, branched, inflated squamules that appear densely pruinose because their cortical hyphae bear characteristically swollen, densely spinose end cells (acanthohyphidia); this species has never been observed fertile. The common Cora glabrata is foliose, forming large, radially zonate, conch-like, often tiled thalli, when fertile with circular lines of basidiocarps on its lower side. Dictyonema is distinguished by filamentous cyanobionts and distinctly filamentous thalli that are homomereous (i.e., not distinctly layered); all species of Dictyonema s.str. have trichomes (filamentose cyanobacterial photobionts) closely enveloped by fungal cells of a jigsaw pattern. In D. sericeum thallus filaments (i.e., individual fibrils) aggregate to form shelf-like structures similar in appearance to polyporoid bracket fungi; basidiocarps develop in irregular patches on the lower side of these shelves. In contrast, fibrils of D. schenkianum grow encrusting their substrate with irregularly to suberect trichomes, occasionally bearing basidiocarps dispersed across the thallus. Two other species in Galapagos show adpressed growth form and are described here as new: Dictyonema pectinatum, which is characterized by large parallel fibrils with paler, papillate tips, and D. galapagoense, characterized by thin trichomes of more squarrish elongate cells. The genus Cyphellostereum is represented by two species: the newly described C. imperfectum and an unnamed Cyphellostereum sp., both phenotypically similar to free-living cyanobacterial filaments. Cyphellostereum imperfectum has narrow photobiont filaments with irregular hyphal sheath leaving interspaces; macroscopically it shows a bluish green thallus with a distinct prothallus. Cyphellostereum sp. has a rather uncommon basidiolichen appearance: thin sctytonematoid fibrils surrounded by straight fungal cells forming shiny tufts. The new combination Cyphellostereum nitidum is also proposed. The ecology and taxonomy of Galapagos basidiolichens is briefly discussed and a key and short descriptions of all species are presented. © Kevin D. Hyde 2011. Source

Sulzbacher M.A.,Federal University of Pernambuco | Baseia I.G.,Grande Rio University | Lucking R.,Botany | Parnmen S.,Botany | Moncada B.,University of Caldas
Bryologist | Year: 2012

Many of the species living on our planet remain undiscovered, among these over one million Fungi. One approach to account for undescribed species is the search in unusual habitats. Here we report on the unexpected finding of a new species of Lepidostroma (Atheliales: Lepidostromataceae) from the semi-arid Caatinga biome in northeastern Brazil. It is only the fifth species of this enigmatic genus and only the third from the Neotropics, and the fourth species to be described within the past four years. DNA was extracted and the ITS and nuLSU partitions of the nuclear rDNA were sequenced. A phylogenetic tree was computed under a maximum likelihood framework using an alignment of selected Basidiomycota (Atheliales, Agaricales, Boletales, Russulales, Cantharellales). The new species differs from other species in the genus by the crustose rather than squamulose thallus. Molecular sequence data place the species as unsupported sister to Lepidostroma akagerae. The crustose thallus resembles that of Multiclavula species, which are phylogenetically unrelated. This study underlines that novel lichenized Fungi can be discovered in unusual habitats. The Caatinga vegetation is to a large extent threatened by habitat destruction and the discovery of such an unusual species underlines the importance of this unique biome for conserving diversity in tropical South America. Systematically, the new species is relevant because it represents the only species of Lepidostroma with a crustose, Multiclavula-like thallus, presenting a striking example of parallel evolution in lichenized Basidiomycota. Copyright © 2012 by The American Bryological and Lichenological Society, Inc. Source

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