Revisiting generic concepts in the Teloschistaceae (lichenforming Ascomycota) using molecular phylogenetics, algorithmic taxa delimitation and molecular networks

In systematics, genera delimitation is constantly changing as taxonomic units above species level are not standardised. The Teloschistaceae, a diverse family of lichenised fungi, represents an extreme example of this where the number of genera has increased tenfold in the last decade. Many of these genera are based solely on molecular clades which makes the current classification confusing for taxonomists and impenetrable for non-experts. As a result, no widely accepted classification exists, and most people still follow pre-molecular classifications. Here I show that at least 37 genera are either polyphyletic or nested within other genera and that the subfamily Brownlielloideae is invalid due to use of contaminated and misidentified DNA sequences. Algorithmic taxa delimitation and molecular networks show clear signal at the genus level suggesting both as useful additions to the taxonomic toolkit for delimiting higher taxa. This study represents a starting point for delimiting stable, standardised genera in the Teloschistaceae with the aim of producing an intuitive, evolutionary-relevant classification of the family.