Phylogenetic and chemical studies in the potential psychotropic species complex of Psilocybe atrobrunnea with taxonomic and nomenclatural notes

Abstract

Five Psilocybe species with unresolved systematic position ( P. atrobrunnea , P. laetissima , P. medul- losa , P. pelliculosa , and P. silvatica ) were investigated using four molecular markers (EF1-α, ITS, LSU, and IGS). Phylogenetic analysis revealed that with the exception of P. laetissima , which is now rightfully classified in the genus Leratiomyces , all investigated species belong to Psilocybe sect. Psilocybe . For the first time, psychotropic compounds psilocin and psilocybin were detected in P. medullosa using gas chromatography-mass spectrometry. On the contrary, neither psilocin, nor psilocybin was detected in P. atrobrunnea and negative results were also obtained from mycelia grown in vitro on tryptamine/tryptophan-amended media. These results strongly suggest that biosynthesis of these alkaloids was lost in P. atrobrunnea . With the exception of minor differences detected in EF1-α marker, all sequences of American and European collections of P. atrobrunnea were identical. On the other hand, a thorough nomenclatural study revealed that the name P. atrobrunnea must be considered dubious; the oldest available candidate name, P. fuscofulva , was therefore adopted. The molecular data suggests that morphologically identical American P. silvatica and European P. medullosa likely represent distinct species; epitypes of both taxa were therefore designated.