RESUMO
Species of the ectomycorrhizal (ECM) family Cortinariaceae (Agaricales, Agaricomycetes, Basidiomycota) have long been considered impoverished or absent from lowland tropical rainforests. Several decades of collecting in forests dominated by ECM trees in South America's Guiana Shield is countering this view, with discovery of numerous Cortinariaceae species. To date, ~12 morphospecies of this family have been found in the central Pakaraima Mountains of Guyana. Here, we describe three of these as new species of Cortinarius and two as new species of Phlegmacium from forests dominated by the ECM tree genera Dicymbe (Fabaceae subfam. Detarioideae), Aldina (Fabaceae subfam. Papilionoideae), and Pakaraimaea (Cistaceae). Macromorphological, micromorphological, habitat, and DNA sequence data are provided for each new species.
Assuntos
Agaricales , DNA Fúngico , Fabaceae , Micorrizas , Filogenia , Guiana , DNA Fúngico/genética , Micorrizas/classificação , Micorrizas/genética , Agaricales/classificação , Agaricales/genética , Agaricales/isolamento & purificação , Fabaceae/microbiologia , Análise de Sequência de DNA , DNA Espaçador Ribossômico/genética , Cortinarius/classificação , Cortinarius/genética , Cortinarius/isolamento & purificação , Ecossistema , DNA Ribossômico/genética , Esporos Fúngicos/citologia , Esporos Fúngicos/classificaçãoRESUMO
The Neotropics have recently emerged as an important region for studies of tropical ectomycorrhizal (ECM) fungi. Specific neotropical areas with high ECM host tree densities have ECM fungal diversities rivaling those of higher-latitude forests. Some forests of the Guiana Shield are dominated by endemic ECM trees of the Fabaceae, including species of Dicymbe (subfam. Detarioideae), Aldina (subfam. Papilionoideae), and Pakaraimaea (Cistaceae). One of the most species-rich ECM fungal families present in each of these systems is Russulaceae. Long-term sampling in forests in Guyana's Pakaraima Mountains has revealed a number of species of the Russulaceae genera Lactarius, Lactifluus, and Russula. In this study, we document a previously unknown, distinct lineage of Lactarius subg. Plinthogalus containing eight species from the Guiana Shield. Here, we describe five of these species from Guyana as new to science: Lactarius humiphilus, Lactarius mycenoides, Lactarius guyanensis, Lactarius dicymbophilus, and Lactarius aurantiolamellatus. Morphological descriptions, habit, habitat, and known distribution are provided for each new species. Sequence data for the barcode internal transcribed spacer (ITS) locus are provided for types and most other collections of the new taxa, and a molecular phylogenetic analysis based on the ITS, 28S, and RPB2 (second-largest subunit of the RNA polymerase II) loci across the genus Lactarius corroborates their morphology-based infrageneric placement. The discovery of this lineage changes our insights into the biogeography and evolutionary history of Lactarius subg. Plinthogalus.
Assuntos
Agaricales , Basidiomycota , Fabaceae , Micorrizas , Humanos , Guiana , Filogenia , DNA Fúngico/genética , Agaricales/genética , Micorrizas/genética , Fabaceae/microbiologiaRESUMO
The family Steccherinaceae includes genera with smooth, hydnoid, and poroid hymenophores, monomitic to dimitic hyphal systems, and generative hyphae with clamps or simple septa. Steccherinum is the largest genus in the family, with a worldwide distribution, and is characterized mainly by a dimitic hyphal system and presence of thick-walled encrusted cystidia. Species traditionally included in Steccherinum, however, have been transferred to other genera based on results of molecular phylogenetic analyses. Even though knowledge of Steccherinaceae has increased in the past few years, very little is known about the hydnoid species of the family, especially from the Neotropics. In this study, we present morphological and phylogenetic analyses on hydnoid specimens of Steccherinaceae collected in the Neotropics. Molecular data of nuc internal transcribed spacer region ITS1-5.8S-ITS rDNA (ITS) and portions of nuc 28S rDNA (28S), translation elongation factor 1-α (tef1), and the largest subunit of RNA polymerase II (rpb1) were obtained from Brazilian collections. Types and original collections were studied for morphological comparison. Samples we studied grouped in four different genera of Steccherinaceae: Cabalodontia, Etheirodon, Metuloidea, and Steccherinum. Three new neotropical species, Cabalodontia delicata, Etheirodon purpureum, and Steccherinum larssonii, are described. In addition, the new combinations Cabalodontia albofibrillosa and Metuloidea reniformis are proposed. The four genera presented in this study are compared and discussed in detail.
Assuntos
Polyporales , DNA Fúngico/genética , DNA Ribossômico/genética , DNA Espaçador Ribossômico/genética , Filogenia , Polyporales/genética , RNA Ribossômico 28S , Análise de Sequência de DNARESUMO
Stypella vermiformis is a heterobasidiomycete producing minute gelatinous basidiocarps on rotten wood of conifers in the Northern Hemisphere. In the current literature, Stypella papillata, the genus type of Stypella (described from Brazil), is treated as a taxonomic synonym of S. vermiformis. In the present paper, we revise the type material of S. papillata and a number of specimens addressed to S. vermiformis. As a result, the presumed synonymy of S. papillata and S. vermiformis is rejected and the genus Stypella is restricted to the single species S. papillata. Morphological and molecular phylogenetic studies of specimens from the Northern Hemisphere corresponding to the current concept of S. vermiformis uncovered three species from two newly described genera. S. vermiformis s.str. is distributed in temperate Europe and has small-sized basidia and basidiospores, and it is placed in a new genus, Mycostilla. Another genus, Stypellopsis, is created for two other species, the North American Stypellopsis farlowii, comb. nov., and the North European Stypellopsis hyperborea, sp. nov. Basidia and basidiospores of Stypellopsis spp. are larger than in Mycostilla vermiformis but other morphological characters are very similar. In addition, Spiculogloea minuta (Spiculogloeomycetes, Pucciniomycotina) is reported as new to Norway, parasitising basidiocarps of M. vermiformis and Tulasnella spp.