Sporidesmiella lignicola sp. nov., a new hyphomycetous fungus from freshwater habitats in China

Freshwater fungi, growing on submerged wood, can promote the degradation of organisms and the reuse of rotten wood energy and play key roles in freshwater ecosystems. Here, a new hyphomycetous fungus, Sporidesmiella lignicola, was isolated and identified from submerged wood samples collected in a small stream in Jiangxi Province, south-eastern China. The new taxon was studied, based on morphological characters and phylogenetic analyses combined with LSU, ITS, TEF1α and RPB2 sequences data. Sporidesmiella lignicola was morphologically characterised by its pink colonies on PDA medium in prophase, macronematous, mononematous, solitary, brown, septate, unbranched, straight or slightly flexuous conidiophores with holoblastic, polyblastic, integrated, terminal, pale brown conidiogenous cells and cylindrical, narrowly clavate, broadly obovoid to cuneiform, 3–4-distoseptate, olivaceous brown or brown conidia with rounded apex. A phylogenetic tree was constructed, based on the combination of LSU, ITS, TEF1α and RPB2 sequences data.

Additions to Distoseptispora (Distoseptisporaceae) associated with submerged decaying wood in China

In this study, five aquatic hyphomycetous taxa were collected and isolated from submerged wood in Lancang River located in the northwestern Yunnan Province of China. Phylogenetic analyses based on combined LSU, ITS, tef1α and rpb2 sequence matrix indicated that those five taxa belonging to Distoseptispora (Distoseptisporaceae), and they can be recognized as four species which two are introduced as new species (Distoseptispora euseptatensis and D. yunnanensis) and two are identified as D. aquatica and D. tectonae. Two isolates of the new species Distoseptispora euseptatensis formed a distinct clade among Distoseptispora species (basal to D. suoluoensis and D. bambusae) with good support (ML 100%, MP 100%, BI 1.00 PP). Distoseptispora yunnanensis clustered together with D. euseptatensis, but they are difference in the size of conidiophore and conidia. Corresponding illustrations, descriptions and phylogenetic evidences are provided to justify the placement of our newly collected Distoseptispora taxa.

Freshwater hyphomycetes in Sordariomycetes: two new species of Tainosphaeria (Chaetosphaeriaceae, Chaetosphaeriales) from Thailand

Ongoing investigation of diversity and taxonomy of lignicolous freshwater fungi in Thailand have revealed plenty of new hyphomycetous species. In this study, Tainosphaeria aquatica sp. nov. and T. thailandense sp. nov., occurred on submerged wood in Thailand, are described and illustrated based on the evidences of morphological characters and phylogenetic analysis of combined LSU, ITS and TEF1-α dataset. Tainosphaeria aquatica is characterized by hyaline, 0–3-septate, cylindrical to long fusiform conidia with hair-like, hyaline appendages at both ends. Tainosphaeria thailandense is distinct in having laurel-green, 0–1-septate, reniform to ellipsoidal conidia with polar appendages. A synopsis of morphological characteristics of Tainosphaeria species is provided.

Rhexodenticula aquatica (Sordariomycetidae genera incertae sedis), a novel hyphomycete from freshwater in Thailand

During our surveys of freshwater fungi on submerged wood in the Greater Mekong Subregion, a rhexodenticula-like taxon was collected, described and illustrated. The new collection is identified based on analyses of combined LSU, SSU, ITS and TEF sequence data, and morphological comparison with other Rhexodenticula species. According to the morphology and molecular analysis, our collection is not known before and hence, we introduce here as Rhexodenticula aquatica sp. nov. This species is characterized by macronematous, subcylindrical, unbranched conidiophores, polyblastic, terminal conidiogenous cells and fusiform, 3-septate, verruculose conidia, and schizolytic conidial secession. Rhexodenticula is referred to Sordariomycetidae genera incertae sedis due to its unstable phylogenetic placement in Sordariomycetidae.

Two new species of Minimelanolocus (Herpotrichiellaceae, Chaetothyriales) from submerged wood in Yunnan, China

During a survey on diversity of freshwater fungi along a north-south latitudinal gradient in Asia, three fresh specimens of Minimelanolocus were collected from submerged wood in streams in northwestern Yunnan Province, China. Based on their distinct morphological features and phylogenetic analyses of combined ITS, LSU and SSU sequence data, Minimelanolocus nujiangensis and M. clavatus are described as new species and M. submersus was recollected from Yunnan, China. Illustrations and descriptions with notes of the three species are provided. This study increases the known diversity of Minimelanolocus and enriches freshwater fungal resources.

Distoseptispora longispora sp. nov. from freshwater habitats in China

A novel species, Distoseptispora longispora, from submerged wood in Yunnan Province, China, is described and illustrated. The fungus is characterized by macronematous, mononematous, septate conidiophores with monoblastic, integrated, determinate, terminal conidiogenous cells that produce acrogenous, solitary, obclavate, elongated, distoseptate conidia. SSU-ITS-LSU sequence analyses were used to infer the phylogenetic relationship between D. longispora and related species. Both molecular analyses and morphological data well support D. longispora as an independent taxon. A key to Distoseptispora species is provided.

Xylomyces (Aliquandostipitaceae, Jahnulales) freshwater hyphomycetes from the Brazilian Amazon

Xylomyces is characterized by the absence of conidiomata, conidiophores, conidiogenous cells, and conidia. The genus only produces chains of large, dark, thick-walled, dry, multiseptate chlamydospores with or without constricted septa. During an investigation of aquatic hyphomycetes on submerged wood and leaf litter in a stream in the Brazilian Amazon, we found four of the accepted eight species of Xylomyces. Xylomyces acerosisporus, X. aquaticus, and X. foliicola are new records to the Brazilian Amazon, while X. giganteus is a new record for the southern Amazonian region. Xylomyces giganteus showed the highest relative frequency and occurrence and X. foliicola displayed an intermediate relative frequency and occurrence. Xylomyces acerosisporus and X. aquaticus showed the lowest relative frequency, while X. acerosisporus indicated the lowest relative occurrence. Descriptions, notes, geographic distributions, and illustrations are presented for all species of Xylomyces found in this study. We also provide a key and a table for all species.

Wicklowia phuketensis (Wicklowiaceae, Pleosporales), a novel freshwater taxon from Thailand

An investigation of aquatic fungi in Thailand resulted in the collection and isolation of a new species of Wicklowia (Wicklowiaceae) from submerged wood. Wicklowia phuketensis sp. nov. differs from known species in morphology and multigene phylogenetic analyses. Both W. submersa and W. phuketensis lack appendages at both ends, while W. aquatica has basal appendages. Wicklowia phuketensis differs from other species in the dimensions of the ascomata, asci and ascospores. The combined LSU and SSU sequence data placed the new species within Wicklowiaceae.

Composition and Diversity of Fungal Decomposers of Submerged Wood in Two Lakes in the Brazilian Amazon State of Pará

Aquatic ecosystems in tropical forests have a high diversity of microorganisms, including fungi, which are important decomposers of submerged wood. Despite the importance of their role in decomposition, research concerning the diversity of freshwater fungi from Brazilian Amazonian environments is scarce. The aim of this work was to describe the composition and diversity of fungi present on submerged wood in two lakes of the Brazilian Amazon (State of Pará). Fragments of decaying wood (30 samples per lake) were collected from the Lakes Juá and Maicá. The wood samples were inspected for 6 months in the presence of fungal reproductive structures. Fungi observed in the wood were identified morphologically. Twenty-three taxa were identified in the Lake Juá (10 sexual and 13 asexual) and 26 taxa in the Lake Maicá (17 sexual, 9 asexual). ITS sequences were obtained for 14 taxa to aid in identification. In the Lakes Juá and Maicá, the diversity indices were H': 2.6514 and H': 2.8174, respectively. The Sørensen index of the fungal communities in the studied lakes was 0.3673. This study is the first to describe the fungal biodiversity of two important aquatic environments in Pará, Brazil.