Freshwater fungi in the karst plateau wetlands from Guizhou Province, China: taxonomic novelties in Melanommataceae (Pleosporales)

Three isolates of interest were collected during an investigation of freshwater fungi from wetlands in the karst regions of Guizhou Province, Southwest China. Phylogenetic analyses using ITS, LSU, SSU, and <i>tef-1α</i> gene regions have revealed the placements of these isolates in Melanommataceae (Pleosporales, Dothideomycetes). Based on the morphological and phylogenetic evidence, three new species are introduced: <i>Byssosphaeriachishuiensis</i> <b>sp. nov.</b>, <i>Camposporiumguizhouense</i> <b>sp. nov.</b>, and <i>C.aquaticum</i> <b>sp. nov.</b> <i>Byssosphaeriachishuiensis</i> is sister to <i>B.villosa</i> and forms a basal branch of <i>Byssosphaeria</i> within Melanommataceae. <i>Byssosphaeriachishuiense</i> is similar to <i>B.villosa</i> in ascal size but differs in the ascomata and ascospore sizes, and the ascospores lack appendages. <i>Camposporiumaquaticum</i> is sister to <i>C.guizhouense</i>, and they form a distinct lineage within the genus. Morphologically, <i>C.aquaticum</i> resembles <i>C.guizhouense</i> in its conidial shape but differs in conidial size. Additionally, PHI analysis is performed to further reveal that <i>C.aquaticum</i> and <i>C.guizhouense</i> have no significant recombination with related taxa. <i>Neobyssosphaeria</i> is synonymized under <i>Byssosphaeria</i>, and accordingly, <i>Byssosphaeriaclematidis</i> <b>comb. nov.</b> is proposed to accommodate <i>Neobyssosphaeriaclematidis</i>. The descriptions, illustrations, and notes of the novel taxa are provided along with an updated phylogenetic tree of Melanommataceae. Two synopses of the species in <i>Byssosphaeria</i> and <i>Camposporium</i> are also provided.