A new species, Chaetopsina aquatica, collected from the River Nile, Sohag, Egypt, is described and illustrated. Phylogenetic analyses of the combined ITS and LSU rDNA placed the new species within Chaetopsina as a phylogenetically distinct species. Chaetopsina aquatica formed a basal clade to a node containing C. aurantisalinicola and C. penicillata. The new species is characterized by its longer conidia (20–35.2 × 5–8.5 μm on natural substrate, 27.5–41.5 × 5–7 μm in culture) than those reported in Chaetopsina species.

Safagamyces marinus gen. et sp. nov. was recorded from decaying stem of Phragmites australis inside Safaga mangrove is described and illustrated in this article. Phylogenetic analyses of SSU and LSU rDNA sequences dataset placed the new fungus as a distinct branch basal to a node that contains the three asexual marine genera: Cirrenalia, Cucurbitinus and Pseudolignincola in the family Halosphaeriaceae. The fungus is characterized by straight or slightly curved, branched, smooth, 2-6 septate conidia and the sympodial conidial proliferation. Conidial cells increase in size and pigmentation from hyaline at the base to dark-brown at the apex. The new taxon is compared with other asexual fungi in Halosphaeriaceae.

Water pollution in Egypt is increasing over time, with constant supply of pollutant effluents to the water system from several sources. Water samples were collected for hydrochemical analysis during four successive seasons from some irrigation canals and streams of River Nile in Delta region governorates. There are various correlations patterns between fungal communities and physico-chemical parameters. Air and water temperature were major factors that affect fungal distribution. Calcium and magnesium have inverse correlation on fungal diversity. There was no significant correlation of SO42- and NO2- with distribution of freshwater fungi. Ammonia and phosphate encouraged fungal growth. Salinity played active role in determining fungal diversity and community composition. Changes in species composition were correlated positively with elevated concentrations of NH3+ , and pH in some governorates.

In this study, we introduce a novel saprobic taxon Paraloratospora edkuensis, from a decaying stem of Phragmites australis collected at Lake Edku, El-Behera Governorate, Egypt. Multi-locus analyses of the combined ITS (internal transcribed spacers of rDNA), LSU (nuclear large subunit rDNA) and tef1-α (translation elongation factor) sequence data placed the new taxon within Paraloratospora as a phylogenetically distinct species in a clade containing two aquatic species P. fructigena and P. marina. The new species is characterized by having globose to subglobose, dark brown to black ascomata with a short neck, 4–8-spored, cylindrical to obclavate asci, and 3-septate, hyaline and fusiform ascospores. Paraloratospora edkuensis differs from P. fructigena and P. marina by having smaller ascomata with a single neck, asci with four or eight ascospores, different mycelial colony morphology, and nucleotide differences of 2.1–3 %, 0.6–1.4 %, and 1.3–6.9 % in the ITS, LSU and tef1-α genes, respectively.

This study investigated the diversity of lignicolous freshwater fungi on submerged decaying wood from four plant species: Salix alba, Ziziphus spina-christi, Phoenix dactylifera, and Phragmites australis. Random sampling and baiting techniques were employed in the Nile River and irrigation canals at Sohag Governorate, Egypt, between February 2021 and September 2022. A total of 126 fungal taxa were identified, comprising 48 sexual ascomycetes, 73 asexual ascomycetes, and five Basidiomycetes from 4,448 fungal collections recorded from 1,410 submerged samples. Among the 126 taxa recorded, 17 represent new records for Egypt, including four species that are new to science. Asexual taxa predominated in the fungal community, with a ratio of asexual ascomycetes taxa to sexual ascomycetes of 1.5/1.0. The fungi were mainly distributed within the classes Sordariomycetes (52%) and Dothideomycetes (44%). The number of fungi recorded from Sohag Nile River, EL-Maragha Nile River and EL-Maragha irrigation canal were 98, 97, and 77, respectively. Dictyocheirospora heptaspora was the only species common to all three sites. Fifty-five species were consistently recorded across the three studied sites. One hundred and two taxa were identified from baited samples, while 99 were identified from randomly collected samples. Frequent species included Dictyocheirospora heptaspora (20%), Pseudohalonectria lignicola (17%), Ophioceras commune (16%), Zopfiella latipes (14%), Limnoperdon incarnatum (13%), and Hapalosphaeria deformans (12%). Minutisphaera aspera was reported for the first time in Egypt during this study. Phylogenetic analyses of ITS rDNA sequence data, along with morphological characteristics, were used to identify the new collection.