A Comprehensive Checklist and Ecological Assessment of Eurotiomycetes in Thailand: Substrate and Habitat Associations with The Discovery of a New Insect-associated Species and a New Record

Eurotiomycetes is a diverse class of Ascomycota comprising ecologically and economically important fungi, including numerous saprobes, pathogens, and producers of bioactive compounds. This study presents a comprehensive checklist of Eurotiomycetes species in Thailand, documenting their diversity, taxonomy, and distribution. Data were compiled from published literature up to January 2025. In addition, we analyzed two insect-associated Eurotiomycetes samples collected from Chiang Mai and Chiang Rai provinces. Morphological and multigene phylogenetic analyses using four loci (ITS, BenA, CaM, and Rpb2) were used to confirm the taxonomic placements of the new isolates. The checklist records 338 species of Eurotiomycetes. A distribution map highlights regions of high fungal diversity and reveals distinct ecological patterns across different habitat types. Notably, 46 provinces were identified as under-sampled (with fewer than 10 species recorded), while 27 provinces exhibited particularly high species richness. The genera Pyrenula, Aspergillus, Penicillium, and Talaromyces are the most frequently reported Eurotiomycetes in Thailand. In this study, we introduce Aspergillus ceranae, a novel species assigned to Aspergillus section Circumdati, series Sclerotiorum, isolated from the dead Asian honey bee (Apis cerana), and report Aspergillus tamarii associated with the cicada, Tanna japonensis in Thailand. This checklist serves as a vital reference for Eurotiomycetes in Thailand, highlighting key taxa and under-sampled regions, and emphasizing the need to investigate unexplored substrates. New findings contribute to a deeper understanding of the diversity and ecology of Aspergillus and other Eurotiomycetes, supporting future efforts in fungal taxonomy, biodiversity conservation, and ecological research in Thailand.