Studies in the Panaeolus papilionaceus complex (Agaricales, Galeropsidaceae) : two new species discovered in the Dominican Republic and Australia

Abstract

Dominican and Australian collections morphologically assignable to the “Panaeolus papilionaceus complex” were studied using morphological and molecular (nrITS) data. Two new species are described: P. pantropicalis from the Dominican Republic and Australia, and P. detriticola from Australia. A morphological and molecular revision of the holotype and three paratypes of P. papilionaceus var. parvisporus revealed that they do not all represent the same taxon. The holotype was revised morphologically but no usable sequences could be generated from it, the Brazilian paratype is molecularly conspecific with the species described here as P. pantropicalis and the two German paratypes are molecularly conspecific with several collections in GenBank identified as P. retirugis. These German paratypes, geographically and microscopically closest with the holotype, are accepted as reliable representative collections of P. papilionaceus var. parvisporus here combined at the species level. Our phylogenetic analysis identifies two major clades containing the “P. papilionaceus species complex”: P. papilionaceus clade and P. parvisporus clade. P. campanulatus, P. retirugis and P. sphinctrinus are treated as synonyms of P. papilionaceus, while the “small-spored” descriptions of P. retirugis are treated as P. parvisporus comb. nov. We also provide the first report of P. antillarum from the Dominican Republic and the first modern colour image of P. nirimbii.