The First Molecular Phylogenetic Assessment of Agaricus iodosmus and A. xanthodermus (Agaricaceae, Agaricomycotina) from Türkiye Based on Nuclear ITS and LSU rDNA Sequences

This study presents the first molecular phylogenetic assessment of two poisonous fungal species, Agaricus iodosmus and A. xanthodermus, belonging to section Xanthodermatei, and reports a new locality record from the Burdur Province. Taxonomic identification was initially based on a comprehensive morphological characterization and subsequently confirmed using analyses of nuclear ribosomal internal transcribed spacer (ITS) and large subunit (LSU) rDNA sequences. Phylogenetic relationships were inferred using maximum likelihood (ML) and Bayesian methods, confirming their systematic placement within A. section Xanthodermatei. This study provides novel distributional data for the two toxic fungi in Türkiye and underscores the critical role of integrative molecular approaches for the precise identification and phylogenetic classification of Agaricus species.