Phylogenetic and taxonomic studies in Artomyces and Clavicorona (Homobasidiomycetes: Auriscalpiaceae)

Abstract

Clavicorona and its two subgenera, Clavicorona and Ramosa, are reevaluated based on analysis of nuclear ribosomal ITS and LSU DNA sequences, morphological characterizations, and limited mating analyses. Sequence data and morphological characters show that species of subg. Ramosa are not closely related to Clavicorona taxophila, type species of Clavicorona, but that C. taxophila seems more closely related to the euagaric group. This confirms the recognition of the segregate genus Artomyces Jülich. Fifteen species are recognized in Artomyces, including seven species described as new. Two putative new taxa are discussed, but not named. Clavicorona microspora is transferred to Artomyces. A morphological description of each species is provided as is a key to the species of Artomyces. Mating analyses helped to identify isolates of some Costa Rican collections as either A. pyxidatus or A. stephenii. There is significant variability within the ITS region which ranged from 629 to 740 bp among Artomyces species. Although phylogenetic estimations and distance trees based on ITS sequences revealed little resolution in the basal nodes, five major and two monospecific clades are identified. Four Old World - New World sibling species disjunctions are identified and may have resulted from repeated radiation events from a hypothesized Gondwanan origin. Sequence divergence between collections from geographically separated populations of widely distributed species is higher than between collections of species with restricted ranges.