Exploring the Diversity and Systematics of Phaeosphaeriaceae: Taxonomic Novelties from Ecologically Diverse Habitats and Their Phylogenetic Resolution

SIMPLE SUMMARY: Our study describes several species of Phaeosphaeriaceae found in terrestrial habitats in Sichuan Province, China. We used morphological and molecular data to accurately delimit these species and determine their taxonomic relationships within the family. Our findings contribute to understanding fungal diversity in China and provide a basis for future studies exploring the ecological roles and biotechnological potential of these fungi. Additionally, our multi-gene phylogenetic approach provides increased accuracy and resolution in the delimitation of species boundaries within Phaeosphaeriaceae. ABSTRACT: The family Phaeosphaeriaceae is a diverse group of ascomycetous fungi that are commonly found in terrestrial habitats worldwide. In recent years, there has been increasing interest in the biodiversity of Phaeosphaeriaceae in China, particularly in Sichuan Province, which has not been fully explored for its high fungal diversity. In our study, we conducted extensive surveys in Sichuan Province to identify and describe new species of Ascomycota with diverse habitats. Here, we present a taxonomic revision of Phaeosphaeriaceae with taxonomic novelties from terrestrial habitats in Sichuan Province based on a multi-gene phylogenetic approach. Our study focuses on the description of four new species of Phaeosphaeriaceae, representing novel additions to the diversity of this fungal family. Using a combination of morphological and molecular data, we provide detailed descriptions of the new taxa and their placement within the family. Additionally, we discuss the phylogenetic relationships of these new taxa with other members of Phaeosphaeriaceae, providing insights into the correct taxonomic classification of the family. Our taxonomic revision contributes to understanding fungal diversity in China and provides a foundation for future studies investigating the taxonomy and ecological roles of Phaeosphaeriaceae fungi. Furthermore, our multi-gene phylogenetic approach provides increased resolution and accuracy in the delimitation of species boundaries within the family. Our study highlights the importance of continued exploration and taxonomic revision in order to fully understand the diversity and distribution of fungal species in China and beyond. New species: Paraloratospora sichuanensis, Phaeosphaeria chengduensis, P. sichuanensis, and Septoriella shoemakeri. New combinations: Paraloratospora breonadiae, P. fructigena, Septoriella ammophilicola, S. asparagicola, S. festucae, S. luzulae, and S. verrucispora. New names: Septoriella paradactylidis, and S. neomuriformis.