Russulaceae of the Pakaraima Mountains of Guyana. IV. New species forming a distinct lineage of Lactarius subg. Plinthogalus
Abstract
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 […]
Diversity and distribution of tropical ectomycorrhizal fungi
Abstract
The tropics were long considered to have few ectomycorrhizal fungi, presumably due to a paucity of ectomycorrhizal host plants relative to higher-latitude ecosystems. However, an increase in research in tropical […]
Global patterns in endemicity and vulnerability of soil fungi
Abstract
Fungi are highly diverse organisms, which provide multiple ecosystem services. However, compared with charismatic animals and plants, the distribution patterns and conservation needs of fungi have been little explored. Here, […]
Biogeographic history of a large clade of ectomycorrhizal fungi, the Russulaceae, in the Neotropics and adjacent regions
Summary
- The biogeography of neotropical fungi remains poorly understood. Here, we reconstruct the origins and diversification of neotropical lineages in one of the largest clades of ectomycorrhizal fungi in the […]
Ectomycorrhizal fungal community assembly on seedlings of a Neotropical monodominant tree
Summary
Ectomycorrhizal tree species may benefit from positive plant–soil feedbacks, where soil environments near adult trees enhance conspecific seedling growth and survival. In tropical monodominant forests, seedling survival is particularly important, […]
Implications of a long-term mast seeding cycle for climatic entrainment, seedling establishment and persistent monodominance in a Neotropical, ectomycorrhizal canopy tree
Summary
In Guyana, we examined temporal variability and ecological consequences of seedbased reproduction in the ectomycorrhizal, monodominant leguminous canopy tree Dicymbe corymbosa using an extensive 2003–2017 dataset encompassing two masting events. […]
New species of Amanita subgen. Lepidella from Guyana
Summary
New species of Amanita subgen. Lepidella are described from Guyana. Amanita cyanochlorinosma sp.nov., Amanita fulvoalba sp. nov., and Amanita guyanensis sp. nov. represent the latest additions to the growing body of newly described ectomycorrhizal fungi native to Dicymbe-dominated tropical rainforests. Macro- […]
Ectomycorrhizal associations in the tropics – biogeography, diversity patterns and ecosystem roles
Summary
Ectomycorrhizal (ECM) associations were historically considered rare or absent from tropical ecosystems. Although most tropical forests are dominated by arbuscular mycorrhizal (AM) trees, ECM associations are widespread and found in […]
Soil niche partitioning in ectomycorrhizal fungi
Temperate ectomycorrhizal (ECM) fungi show segregation whereby some species dominate in organic layers and others favor mineral soils. Weak layering in tropical soils is hypothesized to decrease niche space and therefore reduce the diversity of ectomycorrhizal fungi.
New Neotropical genus of Agaricales
A new genus and three new species of Agaricales are described from the Pakaraima Mountains of Guyana in the central Guiana Shield. All three of these new species fruit on the ground in association with species of the ectomycorrhizal (ECM) tree genus Dicymbe (Fabaceae subfam. Caesalpinioideae) and one species has been shown to form ectomycorrhizas. Multi-locus molecular phylogenetic analyses place Guyanagarika gen. nov. within the Catathelasma clade, a lineage in the suborder Tricholomatineae of the Agaricales. We formally recognize this ‘Catathelasma clade’ as an expanded family Catathelasmataceae that includes the genera Callistosporium, Catathelasma, Guyanagarika, Macrocybe, Pleurocollybia, and Pseudolaccaria. Within the Catathelasmataceae, Catathelasma and Guyanagarika represent independent origins of the ectomycorrhizal habit. Guyanagarika is the first documented case of an ECM Agaricales genus known only from the Neotropics.
New Elaphomyces species from Guyana and Cameroon
The sequestrate false truffles Elaphomyces favosus, E. iuppitercellus, and E. labyrinthinus spp. nov. are described as new to science from the Dja Biosphere Reserve, Cameroon. Elaphomyces adamizans sp. nov. is described as new from the Pakaraima Mountains of Guyana. The Cameroonian species are the first Elaphomyces taxa to be formally described from Africa, occurring in lowland Guineo-Congolian tropical rainforests dominated by the ectomycorrhizal (ECM) canopy tree Gilbertiodendron dewevrei (Fabaceae subfam. Caesalpinioideae). The Guyanese species is the third to be discovered in lowland tropical South America, occurring in forests dominated by the ECM trees Pakaraimaea dipterocarpacea (Dipterocarpaceae) and Dicymbe jenmanii (Fabaceae subfam. Caesalpinioideae). Macromorphological, micromorphological, habitat, and DNA sequence data are provided for each new species. Molecular and morphological data place these fungi in Elaphomycetaceae (Eurotiales, Ascomycota). Unique morphological features are congruent with molecular delimitation of each of the new species based on a phylogenetic analysis of the rDNA ITS and 28S loci across the Elaphomycetaceae. The phylogenetic analysis also suggests that a common ancestor is shared between some Elaphomyces species from Africa and South America, and that species of the stalked, volvate genus Pseudotulostoma may be nested in Elaphomyces.
New Boletaceae genera from Guyana
Binderoboletus segoi gen. and sp. nov., Guyanaporus albipodus gen. and sp. nov. and Singerocomus rubriflavus gen. and sp. nov. (Boletaceae, Boletales, Basidiomycota) are described from the Pakaraima Mountains and adjacent lowlands of Guyana. Xerocomus inundabilis, originally described from the central Brazilian Amazon and based solely on the type collection, is redescribed from numerous collections from Guyana and transferred into Singerocomus. These boletes occur in Neotropical forests dominated by ectomycorrhizal trees in the genera Dicymbe (Fabaceae subfam. Caesalpinioideae), Aldina (Fabaceae subfam. Papilionoideae) and Pakaraimaea (Dipterocarpaceae). Three of the species were repeatedly found in a multiyear sporocarp survey in Dicymbe corymbosa-monodominant forest. Macromorphological, micromorphological, habitat and multilocus DNA sequence data are provided for each species. A molecular phylogenetic analysis based on a large taxon set across the Boletaceae justifies erection of the new genera.