Pseudosperma arenarium (Inocybaceae), a new poisonous species from Eurasia, based on morphological, ecological, molecular and biochemical evidence

A new mushroom species, Pseudosperma arenarium, is described from sandy soils under poplar and pine in northwestern China and northern Europe. It is identified by its robust form, nearly smooth cap, large spores, and unique DNA. Chemical tests show it contains muscarine, with toxin levels about five times higher in the cap (up to 4302 mg/kg) than in the stem (up to 929 mg/kg), indicating that eating different parts of the mushroom can cause varying severity of poisoning. Other toxins such as amatoxins, ibotenic acid, psilocybin, and psilocin were absent.

Study at a glance

Abstract

In this study, Pseudosperma arenarium is proposed as a new species, based on morphological, ecological, molecular and biochemical evidence. The new species grows on sandy ground under Populus and Pinus sylvestris in north-western China and northern Europe, respectively. It is characterised by the combination of the robust habit, nearly glabrous pileus, large cylindrical basidiospores, thin-walled cheilocystidia and ecological associations with Populus alba × P. berolinensis and Pinus sylvestris and unique phylogenetic placement. Additionally, a comprehensive toxin determination of the new species using ultra-high performance liquid chromatography-tandem mass spectrometry was conducted. Results showed that it was a muscarine-positive species. The content were approximately five times higher in the pilei [4012.2 ± 803.1–4302.3 ± 863.2 mg/kg ( k = 2, p = 95%)] than in the stipes [850.4 ± 171.1–929.1 ± 184.2 mg/kg ( k = 2, p = 95%)], demonstrating the severity of mushroom poisoning when patients consumed different parts of the poisonous mushroom. Amatoxins, phallotoxins, ibotenic acid, muscimol, psilocybin and psilocin were not detected.