Imperator Revision Uncovers New Boletale Species

Matteo Gelardi, Neven Ferenčak, Alona Yu. Biketova, Marko Požnjak, Artemis Diana Treindl, Andrin Gross, Günter Saar, Marco Cartabia, Jacques Guinberteau, László Albert, Michal Mikšík, Eva Zupan, Pierre-Arthur Moreau, Jean-Michel Bellanger, Boris Assyov, Bálint Dima, Alfredo Vizzini reported on 2 Nov 2026 that the bolete genus Imperator required taxonomic revision; the paper appeared in MycoKeys volume 142, issue 335‑413, DOI 10.3897/mycokeys.142.208955 ¹.

The authors noted that I. torosus—a polymorphic Friesian bolete originally described from Central Europe—had long suffered from an unclear species concept, with earlier molecular phylogenetic analyses indicating it was polyphyletic and needed redefinition. The team applied a two‑locus approach using ITS and LSU sequences to generate a robust phylogeny, supplemented by pairwise distance calculations and percent nucleotide similarity analyses, as well as morphological and ecological evidence.

From this work they defined I. torosus sensu stricto (s.str.) based on clear genetic boundaries and distinct macro‑ and micro‑morphological traits. In addition, they described a novel cryptic species, Imperator occultus, which had previously been hidden within the torosus assemblage. Both taxa were illustrated with comprehensive macro‑ and micromorphology drawn from well‑documented collections, providing new diagnostic keys for field identification.

This clarification is significant because Imperator belongs to an important edible mushroom group; accurate taxonomy will help mycologists better identify similar-looking taxa in the wild and has implications for conservation efforts as well as food safety measures.

The study demonstrates how integrating molecular data with traditional taxonomic methods can resolve long‑standing ambiguities in fungal classification, ensuring that future foragers and researchers rely on reliable identifications when assessing biodiversity or evaluating culinary potential. The newly established strict concept of I. torosus s.str., together with the description of I. occultus, provides a more stable foundation for ecological studies across Central Europe’s forest ecosystems.