Establishing species boundaries and new taxa among fungi: recommendations to resolve taxonomic ambiguities

Accurate identification and demarcation of taxa has far reaching implications in mycology, especially when plant pathogens are involved. Yet few publications have seriously proposed recommendations as to how to delineate species boundaries. Morphology, with all its taxonomic disparities, has been the main criterion upon which current fungal species concepts are based and morphologically defined species make up the largest number of named species. Although phylogenomic based studies arguably offer novel insights into classification at higher taxonomic levels, relationships at the species level and recognition of species remain largely controversial and subject to different interpretations. Our recommendations herein will provide a more rational framework based on scientific data on how to delineate species and establish a new taxon.