Saccosoma megasporum sp. nov. from a Mexican Abies religiosa forest

Saccosoma is a small genus within Atractiellomycetes with only seven described species so far. Most species are very rare and endemic to restricted areas. Saccosoma megasporum is described as a new species from Abies religiosa fallen branches in central Mexico. It is characterized by large, subglobose spores (12–16 × 15–17 µm) and white hypochnoid basidiome. This is the eighth described species of Saccosoma and the second species reported from Mexico. This finding highlights the large corticioid species diversity in Abies religiosa forests (the monarch butterfly overwinter refuge). As this ecosystem is seriously threatened by global warming, its conservation is urgently needed to maintain its fungal diversity and ecosystem services.