Morphological, Molecular, and Phylogenetic Studies of Amanita brunnescens from the Cuenca de la Esperanza Protected Natural Area, Guanajuato, Mexico

The study of macrofungi, especially the genus Amanita, is extensive and well-documented. In Mexico, a wide variety of edible and poisonous species is known, underscoring the importance of studying them. In this study, we examined a series of collections from central Mexico whose genetic identification matched Amanita brunnescens, a species native to eastern North America. This species is primarily associated with hardwood forests and some conifers and is characterized by its dark brown to dull brown coloration. However, in the collections from this research, we observed morphological variation that does not fully align with the characteristics described by the original author of the species. This led us to question whether these variable traits correspond to a single species or a species complex within this taxon. To test these hypotheses, we performed maximum-likelihood and Bayesian phylogenetic analyses, which, together with the ASAP and GMYC species delimitation methods, suggest that these morphological differences are likely due to diversification.