New acremonium-like species in the Bionectriaceae and Plectosphaerellaceae

Abstract

Several molecular studies have demonstrated that species traditionally assigned to the form genus Acremonium are polyphyletic, while Acremonium sensu stricto is a central element of the Bionectriaceae (Hypocreales). Based on phenotypic characters and molecular phylogenetic analyses, two new Acremonium species, A. moniliforme and A. dimorphosporum, are described. The former is related to Emericellopsis and is characterized by cylindrical conidia, acicular phialides and abundant moniliform hyphae. Acremonium dimorphosporum resembles Acremonium borodinense. It produces cylindrical, smooth-walled and ellipsoidal, rough-walled conidia. The new genus Brunneomyces is proposed based on three species, including B. brunnescens (formerly A. brunnescens), B. europaeus and B. hominis. All of them are characterized by brown hyphae, sympodial conidiophores and chains of ovoidal to ellipsoidal conidia. Also, the proposed new species Chordomyces albus is characterized by its light-coloured colonies, simple or branched conidiophores, phialides with percurrent proliferations and cylindrical collarettes, and ellipsoidal to cylindrical conidia. The combined analysis of the LSU, ITS, RPB2 and TEF1-α loci supports the inclusion of B. brunnescens, B. europaeus, B. hominis and C. albus in Plectosphaerellaceae.