Use their names: there are no basal, lower, or early diverging fungi.

Abstract

Fungal biologists have embraced phylogenies for understanding the biology of this diverse group in an evolutionary framework. In an attempt to highlight lineages of fungi that are distinct from the most speciose subphylum Dikarya (Ascomycota + Basidiomycota), the terms "early diverging fungi [lineages]" and "basal fungi" have been introduced, typically to refer to any phylum of fungi outside Dikarya. However, these terms are problematic, because they implicitly assume that the traits and taxa outside of Dikarya are ancestral by invoking a "ladder of progress." A simple rearrangement of the tree to deemphasize the species-rich Dikarya shows that the logic that these taxa are "early branching" or "basal" is a fallacy, because it ignores two facts: (i) that all extant lineages of fungi have evolved an equivalent amount of time since a last common fungal ancestor, and (ii) that the "early diverging lineages" are no more related to each other than they are to Dikarya. To support the many mycologists who want to celebrate the understudied lineages outside of Dikarya while ensuring that these lineages are not mistakenly perceived as "less evolved," "more ancient," or of "lower complexity," we propose that the community abandon these terms and simply use formal taxonomic names, e.g. Mucoromycota. Doing so will promote knowledge of these often overlooked branches of the tree of fungal life.