Morphological and phylogenetic analyses reveal two new species of Chaetosphaeriaceae from Jiangxi Province, China

Chaetosphaeriaceae is a group of micro-ascomycetes widely distributed in diverse ecosystems worldwide. Group members are commonly found on decaying wood, leaf litter and in moist soil. However, their diversity in soil habitats, especially in understudied bamboo forest ecosystems, remains poorly characterised. In this study, we isolated chaetosphaeriaceous fungi from soil samples collected from a bamboo forest on Xiangyun Mountain, Jiangxi Province, China. We determined their taxonomic placement using maximum likelihood (ML) and Bayesian inference (BI) analyses of concatenated sequence data from three nuclear loci: the internal transcribed spacer (ITS), the large subunit (LSU), and the translation elongation factor 1-α ( tef 1-α). Our results confirm that these isolates belong to two new species: Chloridium jiangxiense and Paragongromeriza jiangxiensis . We present detailed descriptions and micrographs of both species and compare them with other members of Chaetosphaeriaceae . Our findings not only expand the documented species richness of Chaetosphaeriaceae in Asia but also underscore the importance of bamboo forest soils as a promising niche for discovering previously unrecognised fungal diversity. Detailed descriptions, photomicrographs, and comparisons with phenotypically similar taxa are provided to facilitate future identification and ecological studies.