Octosporella australis sp. nov. and O. jungermanniarum agg. (Pezizales), two notable hepaticolous fungi from Australia
Abstract
Two species of the hepaticolous genus Octosporella (Pyronemataceae, Pezizales) have been recorded from southern Australia on host species that are hitherto unknown as substrates for ascomycetes. Octosporella australis sp. nov. is characterized by large setose ascomata, 3 -or 4-spored asci, large ellipsoidal ascospores, 36-65 x 10-15 µm, with unthickened spore walls at cell poles and occurring on the terrestrial liverwort Lethocolea pansa (Jungermanniales).
Three collections were gathered on Kangaroo Island, South Australia, on seasonally flooded riverbanks. Phylogenetic analyses of the LSU, SSU and EF1-α sequences showed that the collections of this new species form a well-supported monophyletic group and clearly differ from all other species of Octosporella.
The second species was assigned to O. jungermanniarum agg. which is widely distributed in Europe on several unrelated liverworts. The Australian collection deviates in its somewhat narrower ascospores, but molecular analyses placed the studied specimen among European collections of O. jungermanniarum from various host species.
This species infects the liverwort Lophocolea semiteres (Jungermanniales) and was recorded on the Fleurieu Peninsula on mossy rocks. Apart from a single collection of O. nematospora from New Zealand, these Australian collections are the only records of Octosporella species for the whole Southern Hemisphere.
Both species have multinucleate ascospores and O. australis, with predominantly 8-nucleate ascospores, has the highest known number of nuclei in ascospores among all studied species of octosporaceous fungi and the whole family Pyronemataceae.