In: Sydowia 77, (2024): 259-269; ISSN 0082-0598, DOI 10.12905/0380.sydowia77-2025-0259, Published online on December 17th, 2024

Crassistoma norvegicum (Crassistomataceae), a new genus, species and family of Pleosporales from Norway

H. Voglmayr, M. Andreasen*, B. Nordén, W. Jaklitsch

1 Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030 Vienna, Austria
2 Norwegian Institute for Nature Research, 0855 Oslo, Norway
e-mail: mathias.andreasen@nina.no

Voglmayr H., Andreasen M., Nordén B. & Jaklitsch W. (2024) Crassistoma norvegicum (Crassistomataceae), a new genus, species and family of Pleosporales from Norway. – Sydowia 77: 259-269.

Recent field surveys of Ascomycota in Norway revealed a corticolous pyrenomycetoid species with superficial, black, obpyriform ascomata, bitunicate asci and thick-walled brown, fusoid, bicellular ascospores, somewhat reminding of the North American Trematosphaeria cariosa. However, T. cariosa differs ecologically by growing on dead wood rather than on bark of a living tree, and comparison with the holotype of T. cariosa revealed that the Norwegian fungus differed by rounded-obpyriform vs. conical ascomata, a less carbonaceous peridium with a more uneven/rough surface and often with a basal thin tomentum, nonporate ostiolar papilla with bumpy-warty ridge- to collar-like structures and apically free paraphyses and smaller ascospores with a much narrower and lighter brown equatorial zone at the septum, indicating that both represent distinct species. Molecular phylogenetic analyses of a representative multigene LSU-SSU-RPB2-TEF1 matrix of Pleosporales revealed an isolated position of the Norwegian fungus, remote from the generic type of Trematosphaeria, and it is therefore described as a new genus and species, Crassistoma norvegicum, within a new family, Crassistomataceae.

Key words: Molecular phylogeny, Pleosporales, Taxonomy, Trematosphaeria. – 1 new family, 1 new genus, 1 new species.