New anamorph genus Pseudonadsoniella of dark brown yeast-like fungi similar to the genus Nadsoniella in having very slow growth in culture on all nutrient media but differing in showing better development of ‘colony-like formations’ on Saburo agar medium and potato sections as well as showing a phylogenetic affiliation to the family Meripilaceae (Polyporales, Agaricomycotina) after phylogenetic analysis based on ITS nrDNA sequences is described. The new species Pseudonadsoniella brunnea from Antarctic, Argentina, Galindez Island, is described and illustrated.
The position of some species groups appeared to be polyphyletic genera Rigidoporus, Physisporinus and Phaeococcomyces after ITS nrDNA sequences is discussed. Corrections to identification of some specimens of the genera Phlebia, Elmerina, Physisporinus are provided.
Nomenclature of Issatschenko’s species Nadsoniella nigra and its two infraspecific taxa as well as type and voucher confusion of these taxa in molecular study of the members of the genus Exophiala is discussed. It is shown that the anamorph fungus Exophiala sp. CBS 546.82 (VKM F-2137 or ‘voucher Ruban’s strain 365’), hitherto incorrectly recorded as Nadsoniella nigra var. hesuelica (nom. inval.), is a taxon still waiting for describing.
The conclusion that the original Issatschenko’s collection of Nadsoniella nigra (type strain CBS 535.94) and status of the strain Exophiala sp. CBS 546.82 are in urgent need of the modern revision/re-examination is done.