Some new hysteriaceous Fungi from Costa Rica

A molecular phylogenetic reappraisal of the Hysteriaceae, Mytilinidiaceae and Gloniaceae (Pleosporomycetidae, Dothideomycetes) with keys to world species

A reappraisal of the phylogenetic integrity of bitunicate ascomycete fungi belonging to or previously affiliated with the Hysteriaceae, Mytilinidiaceae, Gloniaceae and Patellariaceae is presented, based on an analysis of 121 isolates and four nuclear genes, the ribosomal large and small subunits, transcription elongation factor 1 and the second largest RNA polymerase II subunit. A geographically diverse and high density taxon sampling strategy was employed, including multiple isolates/species from the following genera: Anteaglonium (6/4), Encephalographa (1/1), Farlowiella (3/1), Gloniopsis (8/4), Glonium (4/2), Hysterium (12/5), Hysterobrevium (14/3), Hysterographium (2/1), Hysteropatella (2/2), Lophium (4/2), Mytilinidion (13/10), Oedohysterium (5/3), Ostreichnion (2/2), Patellaria (1/1), Psiloglonium (11/3), Quasiconcha (1/1), Rhytidhysteron (8/3), and 24 outgroup taxa. Sequence data indicate that although the Hysteriales are closely related to the Pleosporales, sufficient branch support exists for their separation into separate orders within the Pleosporomycetidae. The Mytilinidiales are more distantly related within the subclass and show a close association with the Gloniaceae. Although there are examples of concordance between morphological and molecular data, these are few. Molecular data instead support the premise of a large number of convergent evolutionary lineages, which do not correspond to previously held assumptions of synapomorphy relating to spore morphology. Thus, within the Hysteriaceae, the genera Gloniopsis, Glonium, Hysterium and Hysterographium are highly polyphyletic. This necessitated the transfer of two species of Hysterium to Oedohysteriumgen. nov. (Od. insidenscomb. nov. and Od. sinense comb. nov.), the description of a new species, Hysterium barrianumsp. nov., and the transfer of two species of Gloniopsis to Hysterobreviumgen. nov. (Hb. smilaciscomb. nov. and Hb. constrictumcomb. nov.). While Hysterographium, with the type Hg. fraxini, is removed from the Hysteriaceae, some of its species remain within the family, transferred here to Oedohysterium (Od. pulchrumcomb. nov.), Hysterobrevium (Hb. moricomb. nov.) and Gloniopsis (Gp. subrugosacomb. nov.); the latter genus, in addition to the type, Gp. praelonga, with two new species, Gp. arciformissp. nov. and Gp. kenyensis sp. nov. The genus Glonium is now divided into Anteaglonium (Pleosporales), Glonium (Gloniaceae), and Psiloglonium (Hysteriaceae). The hysterothecium has evolved convergently no less than five times within the Pleosporomycetidae (e.g., Anteaglonium, Farlowiella, Glonium, Hysterographium and the Hysteriaceae). Similarly, thin-walled mytilinidioid (e.g., Ostreichnion) and patellarioid (e.g., Rhytidhysteron) genera, previously in the Mytilinidiaceae and Patellariaceae, respectively, transferred here to the Hysteriaceae, have also evolved at least twice within the subclass. As such, character states traditionally considered to represent synapomorphies among these fungi, whether they relate to spore septation or the ascomata, in fact, represent symplesiomorphies, and most likely have arisen multiple times through convergent evolutionary processes in response to common selective pressures.

On the evolution of the Hysteriaceae and Mytilinidiaceae (Pleosporomycetidae, Dothideomycetes, Ascomycota) using four nuclear genes

We present a molecular phylogenetic analysis for two families within the Pleosporomycetidae (Dothideomycetes), the Hysteriaceae, and the Mytilinidiaceae, using four nuclear genes, the ribosomal LSU and SSU, transcription elongation factor 1 alpha and the second largest RNA polymerase II subunit. Multigene phylogenies provide strong support for the monophyly of the Hysteriaceae and of the Mytilinidiaceae, both within the Pleosporomycetidae. However, sequence data also indicate that both families are not closely related within the subclass. Although core groups for many of the genera in the Hysteriaceae have been defined, Hysterium, Gloniopsis, and Hysterographium are polyphyletic, with affinities not premised on spore septation and pigmentation. Glonium is also polyphyletic, but along two highly divergent lines. The genus lies outside of the Hysteriaceae, and finds close affinities instead with the family Mytilinidiaceae, for which we propose Gloniaceae fam. nov. to accommodate the type, G. stellatum and related forms. The genus Psiloglonium is reinstated within the Hysteriaceae, with P. lineare, as type, to accommodate non-subiculate species, with apically obtuse didymospores. Farlowiella is removed from the Hysteriaceae, but remains within the Pleosporomycetidae. In contrast, despite divergent spore morphologies, the genera Mytilinidion and Lophium form a strongly supported clade, thus defining a highly monophyletic Mytilinidiaceae, adjacent to the Gloniaceae, for which we propose the Mytilinidiales ord. nov. The genus Ostreichnion, previously in the Mytilinidiaceae, is here transferred to the Hysteriaceae. It is concluded that the evolution of the hysterothecium occurred multiple times within the Pleosporomycetidae, and alone it is not a synapomorphic character state for the Hysteriaceae.