During our survey of the diversity of woody litter fungi in China and Thailand, three Hermatomyces species were collected from dead woody twigs of Dipterocarpus sp. (Dipterocarpaceae) and Ehretia acuminata (Boraginaceae). Both morphology and multigene analyses revealed two taxa as new species (Hermatomyces turbinatus and H. jinghaensis) and the remaining collections as new records of H. sphaericus. Hermatomyces turbinatus is characterized by 1) dimorphic conidia, having circular to oval lenticular conidia and 2) turbinate conidia consisting of two columns with two septa composed of 2–3 cells in each column. Hermatomyces jinghaensis is characterized by dimorphic conidia, having circular to oval lenticular conidia and clavate or subcylindrical to cylindrical conidia and consisting of one or two columns with 6–8 cells in each column. Phylogenetic analyses of combined LSU, ITS, tub2, tef1-α and rpb2 sequence data supports the placement of these new taxa within Hermatomycetaceae with high statistical support.
Tag: microbial genetics
Reappraisal of Immotthia in Dictyosporiaceae, Pleosporales: Introducing Immotthia bambusae sp. nov. and Pseudocyclothyriella clematidis comb. et gen. nov. Based on Morphology and Phylogeny
Immotthia is a poorly known genus, and currently, no DNA sequence data are available to ascertain its proper phylogenetic placement and evolutionary relationships with other bitunicate fungi. To date, there are only two species accepted in the genus. During our ongoing research study of bambusicolous fungi in southwest China and Thailand, a fungus associated with stromata of Hypoxylon sp. was found on dead bamboo culms in Loei Province, Thailand. Preliminary morphological identification revealed that the fungal collection belongs to Immotthia. A novel species, Immotthia bambusae, is introduced herein based on a comparison of morphological characteristics with the type specimen of I. hypoxylon (≡ Amphisphaeria hypoxylon Ellis and Everh.), a synonym of I. atrograna (Cooke and Ellis) M. E. Barr. Phylogenetic analyses of a concatenated ITS, LSU, SSU, and TEF1-α DNA sequence matrix showed that Immotthia belongs to Dictyosporiaceae, Pleosporales. Despite I. bambusae strains constituting a supported subclade, they are nested with the genus Pseudocoleophoma. Pseudocoleophoma clematidis is morphologically different from all other Pseudocoleophoma species, while its conidial characteristics are similar to Cyclothyriella. Multigene phylogenetic analyses showed that P. clematidis formed a clade basal to Immotthia, separated from Pseudocoleophoma with strong statistical support. Therefore, we introduce a monotypic genus, Pseudocyclothyriella Phukhams. and Phookamsak, gen. nov. to accommodate the single species, Pseudocyclothyriella clematidis (Phukhams. and K. D. Hyde) Phukhams. and Phookamsak, comb. nov. Detailed descriptions, color micrographs, and phylogenetic trees to show the placement of the new taxa are provided. In addition, an updated taxonomic treatment of the genera Immotthia and Pseudocyclothyriella is also provided based on the study of the type materials and phylogeny generated from DNA sequence data.
Introducing a new pleosporalean family Sublophiostomataceae fam. nov. to accommodate Sublophiostoma gen. nov.
Collections of microfungi on bamboo and grasses in Thailand revealed an interesting species morphologically resembling Lophiostoma, but which can be distinguished from the latter based on multi-locus phylogeny. In this paper, a new genus, Sublophiostoma is introduced to accommodate the taxon, S. thailandica sp. nov. Phylogenetic analyses using combined ITS, LSU, RPB2, SSU, and TEF sequences demonstrate that six strains of the new species form a distinct clade within Pleosporales, but cannot be assigned to any existing family. Therefore, a new family Sublophiostomataceae (Pleosporales) is introduced to accommodate the new genus. The sexual morph of Sublophiostomataceae is characterized by subglobose to hemisphaerical, ostiolate ascomata, with crest-like openings, a peridium with cells of textura angularis to textura epidermoidea, cylindric-clavate asci with a bulbous or foot-like narrow pedicel and a well-developed ocular chamber, and hyaline, fusiform, 1-septate ascospores surrounded by a large mucilaginous sheath. The asexual morph (coelomycetous) of the species are observed on culture media.
Polyphyletic genera in Xylariaceae (Xylariales): Neoxylaria gen. nov. and Stilbohypoxylon
Several genera in Xylariaceae are polyphyletic in phylogenetic trees and represent more than one distinct genus. However, it is challenging to resolve these genera that are often phylogenetically distantly related, because many taxa have never been recollected and sequenced. Those that have been named and sequenced often lack documented characters or herbarium material. In this paper, we use descriptive morphology of fresh collections, and molecular data to resolve some taxonomic problems in Xylariaceae. During the of microfungi on palms in Thailand, we collected several novel xylariaceous taxa. Herein, we introduce a new genus Neoxylaria which is distantly related to Xylaria sensu stricto and a new species Stilbohypoxylon elaeidis. Neoxylaria is characterized by relatively small stromata with conspicuously exposed perithecial contours under a narrowly striped outer layer. Neoxylaria accommodates a species morphologically similar to Xylaria juruensis, which was also collected from palm material in Brazil and X. queenslandica collected from Archontophoenix alexandrae in Australia. As no molecular data exists for these old collections, we have linked them with morphology to our fresh collection and use both molecular data and morphology to introduce the new genus. Neoxylaria juruensis (Henn.) Konta & K.D. Hyde, comb. nov. and N. queenslandica (Joanne E. Taylor, K.D. Hyde & E.B.G. Jones) Konta & K.D. Hyde, comb. nov. are therefore established. Multigene phylogenetic analysis shows that our new species (S. elaeidis) clusters with Stilbohypoxylon sensu stricto (Stilbohypoxylon clade II) and clarifies the nature of the genus. The new species differs from other species in having solitary, smooth stromata and forms synnemata-like structures on the host, but not on the stroma. The novel taxa introduced here are supported by multigene phylogeny and morphology. Comprehensive morphological descriptions, illustrations and a phylogenetic tree to show the placement of new taxa are provided. © 2020. All Rights Reserved.