Alexandre Gonçalves dos Santos Silva-Filho

The genus Phaeotremella Rea was proposed in 1912 to accommodate Phaeotremella pseudofoliacea Rea. However, the proposal to establish this genus was not supported by the scientific community for over a century until the Tremellomycetes were restructured and the Phaeotremella folicae complex was defined based on molecular data. Currently, 23 species of Phaeotremella are known, most of which have been described in Eurasia, and a few species are known only from North America. Records for the Neotropical region are practically nonexistent. Therefore, the objective of this study was to identify the Phaeotremella specimens recently found in the Atlantic Forest, Southern and Southeastern Brazil. The specimens were collected in the mountainous regions of the states of Santa Catarina and Rio de Janeiro, and then subjected to morphological and molecular phylogenetic analyses. Phaeotremella frondosa is for the first time reported for the tropical region, in the Neotropics, and a new species, viz. Phaeotremella bicolorata, is described from Brazil.

Chlorophyllum tenue sp. nov. is described based on morphological and molecular (nrDNA-ITS, nrDNA-LSU) data. The new species belongs to Chlorophyllum sect. Ellipsoidospororum due to its small sized agaricoid basidiomata with furfuraceous pileal squamules, a loose hymenioderm covering, and basidiospores lacking germ pores. As specific characteristics, the new species has light grayish brown to dark cream pileus with a distinct reddish brown umbo breaking up into appressed light brown to rosy beige irregularly shaped squamules, thin context, cylindrical and subradicant stipe, and stipe surface changing color. Microscopically, the new species has ellipsoid basidiospores smaller than 10 µm long, 4-spored basidia, slender clavate-subcapitate cheilocystidia, and pileus covering formed by elements varying from broadly clavate, clavate to slender clavate sinuous. Additionally, Chlorophyllum tenue sp. nov. represents an independent lineage among Chlorophyllum sect. Ellipsoidospororum and is closely related to C. africanum, C. demangei, and C. hortense.

Fungi play a vital ecological role in Neotropical ecosystems, yet their diversity remains poorly documented, particularly in protected areas of Brazil. This study aimed to conduct the first comprehensive assessment of macrofungal diversity along four trails located in the Chapada Diamantina National Park and the Serra do Conduru State Park, both in the state of Bahia, Northeastern Brazil. From the 266 collected macrofungal specimens, 74 representative samples were selected at the order level for molecular identification by sequencing. Taxonomic identification revealed specimens within two phyla, eight orders, 30 families, and 42 genera, with Basidiomycota being predominant (72 taxa, 97%) and represented mainly by Agaricales (47 taxa, 65%), with Entoloma as the most common genus (10 taxa, 13.5%). Phylogenetic analyses confidently identified 17 species, each represented by a single specimen. Additionally, seven specimens were tentatively assigned as confer or affinis to known taxa, 48 specimens were identified only to the genus level, and two were classified at the family level. Notably, five species were recorded for the first time in the state of Bahia: Agaricus furfuripes, Cantharellus guyanensis, Cookeina speciosa, Mycena margarita and Neofavolus teixeirae, with A. furfuripes also representing the first record for Brazil. The findings highlight both the high diversity and the taxonomic knowledge gaps in these ecosystems, reinforcing the need for further morphological and molecular studies to validate potentially novel taxa. This study establishes a taxonomic inventory as an important baseline for the region and highlights the role of responsible tourism and environmental education in conserving macrofungal diversity in Neotropical protected areas.

Pseudohydnum, commonly known as cat's tongue mushrooms, is a monophyletic assemblage within Auriculariales, which encompasses species with gelatinous basidiomata, spathulate, flabellate, or shell-shaped pileus, hydnoid hymenophore, globose to ellipsoidal basidiospores, and longitudinally cruciate-septate basidia. According to the available literature, 16 species have been described in Pseudohydnum, mostly represented in temperate-boreal forests of the Northern Hemisphere. However, the limited morphological, molecular, and ecological information, especially from the Southern Hemisphere ecosystems, does not presently allow a reliable assessment of its taxonomic boundaries nor provide a complete picture of the species diversity in the genus. In an ongoing effort to examine specimens collected in dense and mixed ombrophilous forest fragments (Atlantic Rainforest domain) from Southeastern and Southern Brazil, additional taxa assigned to Pseudohydnum were identified. Four new species are recognized based mostly on characters of the pileus surface, stipe, hymenium, and basidiospores. Molecular phylogenetic analyses based on nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS barcode), partial nuc rDNA 28S, and partial RNA polymerase II largest subunit (RPB1) sequences supported the description of these new taxa. Here, we propose Pseudohydnum brasiliense, P. brunneovelutinum, P. cupulisnymphae, and P. viridimontanum as new species. Morphological descriptions, line drawings, habitat photos, and comparisons with closely related taxa are provided. A dichotomous key for identification of currently known Southern Hemisphere Pseudohydnum species is presented.

The sequestrate fungus Zelleromyces cinnabarinus was originally found beneath pines and was described from Louisiana, USA. Here we re-evaluate the morphology, taxonomy, and distribution of this species based on new specimens across the native range in the southeastern United States (USA), as well as introduced populations in Argentina and Brazil. Internal Transcribed Spacer (ITS) sequences of fungarium specimens indicate that this species is widespread in the southeastern USA with native pines and has been introduced to South America in cultivated pine plantations. An environmental sequence from ectomycorrhizal Pinus roots also confirms the symbiotic association with pines. Our data also indicate that Lactarius taedae, a sequestrate fungus recently described from Brazil, is a later synonym of Zelleromyces cinnabarinus. Lastly, our phylogenetic analysis of ITS sequences suggests that Zelleromyces cinnabarinus is nested within the genus Lactarius, so we recombine this sequestrate species as Lactarius cinnabarinus comb. nov.

Lactifluus subg. Lactariopsis is a well-supported group of milkcaps occurring predominantly in tropical and subtropical ecosystems. This subgenus contains agaricoid and pleurotoid representatives and is the only group with members containing a secondary velum. The results of taxonomic and phylogenetic research into Lactifluus subg. Lactariopsis collected in Brazilian tropical forests (Amazon, Atlantic Rainforests, and Caatinga biomes) of the North and Northeast is presented here. Two new species are described: Lf. aurantioceraceus in sect. Neotropici, and Lf. reniformis in sect. Multicipites, newly delimited here . In addition, Lf. neotropicus has had its distribution expanded to the Caatinga biome, Lf. dunensis was confirmed in Lf. sect. Neotropici with new records from French Guiana, and Lf. annulifer was re-collected from the type locality. A combined dataset of nuclear rDNA internal transcribed spacer region and nuclear large subunit amplified sequences was analyzed and, based on its phylogenetic hypothesis, the two novel taxa and the new section were confirmed .

During nocturnal field expeditions in the Brazilian Atlantic Rainforest, an unexpected bioluminescent fungus with reduced form was found. Based on morphological data, the taxon was first identified as belonging to the cyphelloid genus Maireina, but in our phylogenetic analyses, Maireina was recovered and confirmed as a paraphyletic group related to genera Merismodes and Cyphellopsis. Maireina filipendula, Ma. monacha, and Ma. subsphaerospora are herein transferred to Merismodes. Based upon morphological and molecular characters, the bioluminescent cyphelloid taxon is described as the new genus Eoscyphella, characterized by a vasiform to urceolate basidiomata, subglobose to broadly ellipsoid basidiospores, being pigmented, weakly to densely encrusted external hyphae, regularly bi-spored basidia, unclamped hyphae, and an absence of both conspicuous long external hairs and hymenial cystidia. Phylogenetic analyses based on ITS rDNA and LSU rDNA support the proposal of the new genus and confirm its position in Cyphellopsidaceae. Eoscyphella luciurceolata represents a new lineage of bioluminescent basidiomycetes with reduced forms.

A novel Leucocoprinus species was collected from the semi-arid region of Brazil in the Caatinga domain.Leucocoprinus rhodolepis is described based on morphological data. It is well characterized by its white pileus with distinct orange-pink pileal squamules at the center, ellipsoid basidiospores measuring 6.9-7.8 × 4.9-5.9 μm lacking an apical germ pore, and clavate to broadly clavate rarely ventricose-capitate cheilocystidia. Detailed macro- and micro-morphological descriptions and illustrations are provided, as well as a comparison with related species and a brief discussion about its conservation status.