Phylogenetic position of freshwater and marine Sigmoidea species: introducing a marine hyphomycete Halosigmoidea gen. nov. (Halosphaeriales)

The aquatic hyphomycete genus Sigmoidea, with freshwater and marine representatives, is re-examined at the morphological and molecular levels. Currently six species are accepted, four from freshwater habitats (S. prolifera, S. aurantiaca, S. contorta, S. praelonga) and two marine species (S. marina, S. luteola). Phylogenetic analyses of the ribosomal small subunit rRNA gene sequences of freshwater and marine Sigmoidea species indicate that the marine species are distantly placed from the freshwater species, S. prolifera and Pseudosigmoidea cranei. The latter species are placed in the Dothideomycetes, in sister clades, with 81% bootstrap support. The phylogenetic placement of both marine Sigmoidea species, inferred from large subunit rRNA gene sequences, was within the genus Corollospora (Halosphaeriales, Sordariomycetes, Pezizomycotina). An undescribed Sigmoidea species isolated from the Baltic Sea and one previously incorrectly identified as S. marina from Japan (S. parvulasp. nov.) formed a clade together with Corollospora quinqueseptata and Varicosporina ramulosa, and were located in a sister group to S. luteola and S. marina. Based on morphological and phylogenetic evidence, Halosigmoidea gen. nov. is proposed to accommodate the three marine Sigmoidea species (S. luteola, S. marina,S. parvula sp. nov.). Identification keys to the genera Halosigmoidea, Pseudosigmoidea and Sigmoidea, and Halosigmoidea species are provided

Thai marine fungal diversity

The marine fungal diversity of Thailand was investigated and 116 Ascomycota, 3 Basidiomycota, 28 anamorphic fungi, 7 Stramenopiles recorded, with 30 tentatively identified. These species have primarily been collected from driftwood and attached decayed wood of mangrove trees. The holotype number of 15 taxa is from Thailand and 33 are new records from the country