Deconica diversity notes type specimens

Deconica (W.G. Sm.) P. Karst.The genus was first proposed by Karsten (1879). For over a century, Deconica was synonymous with the genus Psilocybe (e.g., Guzman 1983; Singer 1986), until the works of Moncalvo (2000, 2002) and Matheny et al. (2006) provided molecular evidence of evolutionary divergence, showing that these genera were distinct and do not share a most recent common ancestor. Subsequently, a nomenclatural proposal was performed by Redhead et al. (2007) to conserve the name Psilocybe for species known to produce hallucinogenic effects and revive the name Deconica for species that lack psychoactivity. Pertinent combinations were made by Noordeloos (2009) for European species and by Cooper (2012), Ramirez-Cruz et al. (2012, 2013a), Silva et al. (2013, 2014), and Bradshaw et al. (2023) for other species around the world. Estimates on the number of species in the genus are between 45 (Kalichman et al. 2020) and 133 (Ramirez-Cruz et al. 2020). The broadest sampling work was made by Ramirez-Cruz et al. (2020), in which 60 species of Deconica (including seven type specimens) were used to determine their phylogenetic relationships based on ITS sequences. In this work, 18 specimens representing distinct lineages were not associated with any previously described species, showing that Deconica could be a much more diverse genus than previously thought. Recently, progress has been made in phylogenomic and chemical aspects of Psilocybe (Bradshaw et al. 2022, 2024), including many type specimens. These advances synergistically affect the genus Deconica, allowing a clear separation between the genera and, consequently, leading to new combinations and synonyms having to be established. Here, new combinations in Deconica are proposed based on phylogenetic analysis employing the barcoding region rDNA ITS (Fig. 1), incorporating sequences derived from Ramirez Cruz et al. (2019, 2020), species hypothesis (SH) sequences from the curated fungal ITS database UNITE (Abarenkov et al. 2010), and eight previously unpublished sequences.