LAUSR

Simple Summary The Greater Mekong Subregion (GMS) has a diverse geographic landscape, and due to its varied environmental conditions, it harbors numerous florae, fauna, and microorganisms. Thus, the biodiversity in this region is exceptionally high. Over recent decades, the number of studies on microfungal diversity in the GMS increased rapidly. However, in the GMS the fungi of terrestrial habitats such as woody litter is still poorly researched. This paper introduces one monotypic genus, five novel species, and two new host records in Didymosphaeriaceae-inhabiting woody plant litter from the GMS and provides morpho-molecular justifications. Abstract The Greater Mekong Subregion (GMS) is known as a diverse geographic landscape and one of the richest biodiversity hotspots in the world with a high fungal diversity. Collections were carried out in terrestrial habitats to determine the diversity of woody litter fungi in the GMS, with an emphasis on northern Thailand and the Yunnan Province of China. Morphological characteristics and multigene phylogenetic analyses of combined SSU, LSU, ITS, and tef1-α supported the placement of the new isolates in the family Didymosphaeriaceae. The phylogenetic affinities of our isolates are illustrated through maximum likelihood and Bayesian inference analyses. Seven species of woody litter fungi were identified, comprising a new monotypic genus, Septofusispora; five novel species (Chromolaenicola sapindi, Dictyoarthrinium thailandicum, Karstenula lancangensis, Septofusispora thailandica, and Spegazzinia jinghaensis); and new host records of two species (Austropleospora archidendri, and Montagnula donacina). Furthermore, this study provides a synopsis of the Montagnula aff. donacina species based on their morphological characteristics, which can be useful in the species-level identifications in this genus.