Charting Taxa inAmanitaSectionAmidella(Basidiomycota:Amanitaceae)

Abstract

AbstractSpecies determination in theAmidellaclade is notoriously difficult, because of the relative dearth of field characters and the rather common occurrence of homoplasies. This results in a substantial number of misnamed and unnamed collections, a misapprehension of the geographic range of known species, and a gross underestimation of the number of species it contains. To assess the diversity that should be considered as part ofAmidella, DNA sequences available for this group were retrieved in public nucleotide databases, using a combination of approaches to achieve a comprehensive representation. Phylogenetic analysis based on the aligned ITS sequences, consistently with the results from other molecular markers (nLSU, RPB2, TEF1, BTUB), suggests five major clades: one containing the type speciesAmanita volvata, another forAmanita ponderosaand allies, a third one (roughly half of all species) withAmanita lepiotoides, and two others without valid species yet. Consensus rRNA folding structures were obtained for these clades, maintaining their congruence and separation from neighbouring congeneric clades. At species level, around 78 clades were delimited, of which only up to 17 can be assigned a valid name, with a few more corresponding to provisional taxa listed in theamanitaceae.orgwebsite. Two further species without assigned sequences might correspond to the proposed clades. The current evidence suggests a rather narrow geographic range for most of these clades. This study provides a phylogeny-arranged outlook of the worldwide distribution ofAmidellaspecies, and a framework for designing clade-specific molecular markers to assist in identification.