Musumecia gen. nov. in the Tricholomatoid clade (Basidiomycota, Agaricales) related to Pseudoclitocybe

Musumecia, a new genus of Agaricales, is described to accommodate the new species Musumecia bettlachensis. Based on a combined ITS– and LSU–rDNA Bayesian, Maximum Likelihood and Maximum Parsimony analysis, Musumecia clearly clusters within the Tricholomatoid clade, where it is sister to Pseudoclitocybe. Musumecia is distinguished from allied genera by a unique combination of macro- and micromorphological characters, including basidiomes with a clitocyboid/hygrophoroid habit, emerging from a fleshy pseudosclerotial mass (pseudosclerotium), decurrent and thick lamellae, a brown darkening of both lamellae and stipe, whitish-cream spore print, elongated nonsiderophilous basidia, smooth, acyanophilous and inamyloid basidiospores, and the absence of both cystidia and clamp-connections. Recent multigene phylogenetic analyses focused on Agaricales (Matheny et al. 2006) have led to the recognition of several monophyletic clades. Among these, the well supported Tricholomatoid clade encompasses four families, the Tricholomataceae R. Heim ex Pouzar s.s, the Lyophyllaceae Jülich, the Entolomataceae Kotl. & Pouzar, the Mycenaceae Overeem, and the Catathelasma clade (Matheny et al. 2006, Ammirati et al. 2007). Recent work by Binder et al. (2010) and Vizzini et al. (2010a) indicate that Infundibulicybe Harmaja, Pseudoclitocybe (Singer) Singer, Trichocybe Vizzini, and Singerocybe Harmaja can be included in the Tricholomatoid clade as well. The aim of this study is to describe a new genus, Musumecia, to accommodate Musumecia bettlachensis sp. nov., a fungus collected from France. According to molecular and morphological features it belongs to the Tricholomatoid clade and is inassimilable to any of the extant genera.