First Report of a Neotropical Agaric (Lepiota spiculata, Agaricales, Basidiomycota) Containing Lethal α-Amanitin at Toxicologically Relevant Levels

A recent collection of Lepiota spiculata from the Dominican Republic is presented here. Macro- and micromorphological features of L. spiculata are described in detail, and its evolutionary (phylogenetic) position within Lepiota sect. Ovisporae, in the subincarnata/brunneoincarnata clade, is assessed on the basis of a combined nrLSU + nrITS + rpb2 + tef1 analysis. Additionally, high levels of deadly amatoxins were detected and quantified in L. spiculata for the first time by HPLC analysis; in particular, α-amanitin was found at concentrations up to approximately 4 mg/g dry weight, which render L. spiculata a potentially lethal mushroom, if ingested.