Molecular phylogeny and species delimitation in the section Longibrachiatum of Trichoderma

► Longibrachiatum clade consists of at least 26 phylogenetic species. ► Many species are allopatric although sympatric species are also present. ► The majority of species lost their ability to sexual reproduction. ► The K/θ method is a useful measure to delineate species in the Longibrachiatum clade. ► The combination of the GCPSR and K/θ method gives the most adequate result for species delineation.