Taxonomy and systematics of lignicolous helicosporous hyphomycetes

Abstract

Helicosporous hyphomycetes are a fungal group with similar coiled or spiral conidial morphology but significant differences in genetic information, resulting in them being distributed in different phyla, classes, orders, and families. However, there are no comprehensive studies for this group. In this study, we have systematically organized the helicosporous taxa, revised their classification and provided a modern taxonomic framework based on morphology and phylogeny. This group encompasses 112 genera and 474 species distributed in three phyla, ten classes, 20 orders and 25 families, while some taxa are classified as incertae sedis within Ascomycota. The illustrations and notes for all helicosporous genera and the drawings of the type or representative species that have not been collected and examined are provided. Additionally, a phylogenetic taxonomic distribution of helicosporous families based on maximum likelihood analysis of LSU, ITS, SSU, tef1-α, and rpb2 sequence data is provided. In addition, we obtained 160 new collections from China and Thailand. Based on molecular evidence and morphological characteristics, six new helicosporous genera viz. Acrohelicosporium, Hyalohelicoon, Hyalohelisphora, Hyalotubeufia, Pseudocirrenalia, and Pseudohelicosporium and 53 new species, viz. Acrohelicosporium abundatum, A. aquaticum, A. guizhouense, A. viridisporum, Berkleasmium hainanense, Helicoma brunneum, H. astrictum, H. dipterocarpi, H. guizhouense, H. sclerotiferum, H. tropicum, H. yinggelingense, Helicoma yunnanense, Helicosporium acropleurogenum, H. brunneisporum, H. changjiangense, H. jiangkouense, H. latisporum, H. ramosiphorum, Helicotubeufia laxisporum, Hyalohelicoon multiseptatum, Hyalohelisphora lignicola, Neohelicomyces acropleurogenus, N. aseptatus, N. edgeworthiae, N. guttulatus, N. lignicola, N. macrosporus, N. qixingyaensis, N. xiayadongensis, N. yunnanensis, N. baihualingense, Neohelicosporium hainanense, N. jianfenglingense, N. latisporum, Parahelicomyces latisporus, Pa. laxisporus, Pa. parvisporus, Paratrimmatostroma helicosporum, Pleurohelicosporium brunneisporum, Pl. hyalosporum, Pl. multiseptatum, Pseudocirrenalia aquialpina, Pseudohelicosporium irregular, Ps. laxisporum, Pseudotubeufia dematiolaxispora, Sclerococcum astrictum, Tubeufia acropleurogena, T. baomeilingensis, T. denticulate, T. subrenispora, T. tropica, and Troposporella guttulata are introduced. Additionally, 37 new records and 22 known species are reported. Furthermore, we synonymize 30 species and provide 30 new combinations. Complete descriptions, illustrations, notes, and phylogenetic trees based on maximum likelihood and Bayesian analyses of LSU, ITS, mtSSU, SSU, tef1-α, and rpb2 sequence data are also provided for the new taxa, new combinations, new records, and known species. A worldwide checklist comprising the distribution, habitat, and availability of molecular data for the accepted helicosporous species is also provided.