Cryptococcus ibericus sp nov., Cryptococcus aciditolerans sp nov and Cryptococcus metallitolerans sp nov., a new ecoclade of anamorphic basidiomycetous yeast species from an extreme environment associated with acid rock drainage in Sao Domingos pyrite mine, Portugal

In this report, we describe three novel asexual basidiomycetous yeast species, Cryptococcus aciditolerans sp. nov. (type strain CBS 10872(T) = SDY 081(T)), Cryptococcus ibericus sp. nov. (type strain CBS 10871(T) = SDY 022(T)) and Cryptococcus metallitolerans sp. nov. (type strain CBS 10873(T) = SDY 190(T)), which were isolated from acid rock drainage collected at the Sao Domingos mine in southern Portugal. Phylogenetic analysis of molecular sequence data indicated that the novel species belong to the order Filobasidiales of the class Tremellomycetes and form a well-separated clade, next to Cryptococcus gastricus and Cryptococcus gilvescens. Since the novel species also share a peculiar ecology, being able to thrive under extreme environmental conditions characterized by very low pH and high concentrations of heavy metals, we designate this combination of phylogenetic and ecological characteristics as an ecoclacle.