Disentangling Phialophora section Catenulatae: disposition of taxa with pigmented conidiophores and recognition of a new subclass, Sclerococcomycetidae (Eurotiomycetes)

A new genus Rhopalophora is described for Phialophora clavispora, a lignicolous species formerly placed in Phialophora section Catenulatae that possesses pigmented conidiophores, phialides with a single conidiogenous locus that occasionally appear as schizophialides, and clavate, aseptate conidia arranged in chains or sometimes in heads. Sexual morphs are not known for this taxon. Phylogenetic analysis of DNA sequences from five loci (nucSSU, ITS, nucLSU, mitSSU, rpb1 and rpb2) of this and related fungi supports the introduction of a new family, Sclerococcaceae, for which we establish the order Sclerococcales. This order belongs to the new subclass Sclerococcomycetidae, a strongly supported clade within the Eurotiomycetes that is basal to a lineage containing the Chaetothyriomycetidae, Coryneliomycetidae and Eurotiomycetidae. Rhopalophora clavispora fits in this new family and is closely related to an isolate of Fusichalara minuta. The Sclerococcales also encompass marine, lignicolous species of Dactylospora, two species of the lichenicolous genus Sclerococcum, and a lineage comprised of strains from the digestive tracts of Neotropical wood-inhabiting beetles. We confirm that Dactylospora is polyphyletic; the phylogenetic placement of D. parasitica, the generic type, remains unknown.