Diversity of Lignicolous Freshwater Fungi from Yuanjiang River in Yunnan (China), with the Description of Four New Species

Yuanjiang River (Red River) is one of the six major water systems in Yunnan Province, which originates from western Yunnan Province. This river system features numerous tributaries, complex terrain, and abundant natural resources. During the investigation on the diversity of lignicolous freshwater fungi in the Yuanjiang River, nine species were collected and identified, five belonging to <i>Dothideomycetes</i> and four to <i>Sordariomycetes</i>. Based on morphology and multigene phylogenetic analyses, four species, namely, <i>Aquadictyospora aquatica</i>, <i>Dictyosporium fluminicola</i>, <i>Myrmecridium submersum</i>, and <i>Neomyrmecridium fusiforme</i>, are described as new species. <i>Dictyocheirospora aquadulcis</i> is reported as a new national record, and <i>Myrmecridium hydei</i> is reported as a new habitat record. <i>Dictyocheirospora rotunda</i>, <i>Halobyssothecium aquifusiforme</i>, and <i>Pseudohalonectria lutea</i> were known earlier from freshwater habitats, but we described them in detail in this paper. This study contributes significantly to the understanding of the diversity of lignicolous freshwater fungi in southwestern China.