Molecular Phylogeny and Morphology Reveal a New Species of Genus Rhodocybe sensu stricto Maire (Entolomataceae; Agaricales) from Pakistan

This study proposes two new species and a new record in the Rhodocybe-Clitopilus clade, based on comprehensive morphological and molecular analyses. The nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS), the large subunit ribosomal RNA gene (LSU), the RNA polymerase II second largest subunit (RPB2) and the translation elongation factor 1-alpha gene (TEF1), were employed to elucidate the relationships of Clitopilus and Rhodocybe. The first species, Clitopilusparasiticus, is capable of infecting the leaves of host plants in the genera Dryopteris and Oplismenus, exhibiting typical biotrophic behaviour while also demonstrating saprophytic growth on soil. Intraspecific comparisons were conducted, examining environmental factors as well as macro- and microscopic characteristics amongst individuals found on different plant hosts. Furthermore, this study reports the new saprophytic species, Rhodocybezijinshanensis and provides a detailed description of Clitopilusbaronii, a newly-recorded species in China.

ABSTRACT A new species of Rhodocybe gangetica (Entolomataceae), is described from the Gangetic Plain of West Bengal, located in eastern India, based on morphological and molecular phylogenetic analyses of the nuclear ribosomal internal transcribed spacer (nrITS). It belongs to the Rhodocybe sect. Rufobrunnea and is characterised by tricholomatoid large basidiomata (75–79 mm), initially convex to plano-convex, broadly parabolic at maturity, slightly olive gray to light yellowish pileus; broadly adnate to subdecurrent pale yellowish white lamellae; a smooth light yellowish white light brown stipe; sub-globose to broadly ellipsoid basidiospores; 4-spored basidia; lageniform with narrow apex cheilocystidia; and unique sequences. A detailed description with illustrations and phylogenetic trees showing the placement of the new species are provided.