Novel discoveries of Xylariomycetidae (Ascomycota) taxa from peat swamp forests and other terrestrial habitats in Thailand.

In a comprehensive survey of fungi conducted in the northern (Chiang Rai Province) and southern (Narathiwat Province) regions of Thailand, several xylariales-like specimens were discovered. Through the integration of molecular phylogeny and morphological analyses, one previously undocumented taxon, Oxydothisnarathiwatensis sp. nov. , was identified, along with Xylariabawanglingensis and Hypoxylonhypomiltum as new host and geographical records from Afzeliaxylocarpa , and Dalbergiacana , respectively. In addition, Annulohypoxylonthailandicum was identified as a new host record from Swieteniamacrophylla in Thailand. The morphological characters, including ascomata, asci, and ascospores, were compared with known Oxydothis , Xylaria , Hypoxylon , and Annulohypoxylon species. Multi-locus phylogenetic analyses based on ITS, LSU, and SSU (for Oxydothidaceae), ITS, rpb2 , tub2 , and act (for Xylariaceae), and ITS, LSU, rpb2 , and tub2 (for Hypoxylaceae) gene regions were carried out to refine the taxonomic classifications of these specimens further. This research contributes to understanding fungal diversity in these ecologically significant regions, highlighting insights into the relationships among xylariales-like species.