An Integrative Taxonomic Study of Parasola (Psathyrellaceae, Fungi) Reveals a New Saprotrophic Species from European Temperate Deciduous Forests

Seventeen collections of the genus Parasola from Croatia were studied with integrative taxonomic methods. Parasola papillatospora is described as a new species, based on morphology and multigene phylogenetic analyses. Its basidiomata were growing on soil in temperate deciduous forests (Quercus petraea, Fagus sylvatica, and Carpinus betulus) on two different localities in NW Croatia. Based on publicly available molecular data, the species is also recorded in Hungary. The most distinctive morphological features of the new species are the characteristics of its basidiospores, (1) the papillate apex and (2) central germ pore (both present in most spores), as well as (3) a highly variable shape. A morphological description of P. papillatospora is accompanied by colour photographs of basidiomata, basidiospores, and cystidia. In this study, a total of 64 DNA sequences from 17 specimens belonging to 10 Parasola species were newly generated. As a result of Bayesian Inference and Maximum Likelihood phylogenetic analyses of the concatenated ITS, LSU, tef-1α, and β-tub gene alignment of Parasola species, P. papillatospora was resolved as an independent clade, a sister to the clade comprising the P. plicatilis species complex. Eight Parasola species (P. auricoma, P. crataegi, P. cuniculorum, P. kuehneri, P. malakandensis, P. megasperma, P. nudiceps, P. plicatilis-similis) are reported for the first time for Croatia and P. malakandensis also for Europe. Colour photographs of basidiomata are provided for all Parasola species new to Croatia except P. kuehneri.