CRYPTOCOCCUS-ANTARCTICUS SP-NOV AND CRYPTOCOCCUS-ALBIDOSIMILIS SP-NOV, BASIDIOBLASTOMYCETES FROM ANTARCTIC SOILS

Cryptococcus albidus, which was described as having maximum growth temperatures (T(max) that vary from <20 to >37-degrees-C, is an apparent exception to van Uden's rule that yeast species generally comprise strains which have T(max) that vary by not more than 5-degrees-C. This exception is dealt with in this paper by the description of phenotypically similar species that have lower T(max) than C. albidus and exhibit no significant DNA similarity to the type strain of C. albidus. Cryptococcus albidosimilis sp. nov., a mesophilic blastobasidiomycete that was isolated from soil of Linnaeus Terrace, Antarctica (type strain, strain MYSW A823-2Y761/70 [= ATCC 76863, = CBS 7711, = NRRL Y-174631), has a T(max) of 30-degrees-C and a guanine-plus-cytosine content of 55 mol%. Cryptococcus antarcticus sp. nov. is a psychrophilic blastobasidiomycete (type strain, strain MYSW A812-20bY693/64 [= ATCC 76663, = CBS 7687, = NRRL Y-174611) is known only from soils of University Valley, Antarctica. C. antarcticus does not exhibit significant DNA similarity with C. albidosimilis, from which it differs phenotypically in its failure to assimilate lactose. The guanine-plus-cytosine content of C. antarcticus is 55 mol%. This species includes four biotypes whose levels of DNA similarity are greater than 72%. The T(max) of these biotypes vary from >15 and <20-degrees-C to >20 and <25-degrees-C. Both habitat temperature (reflected in fatty acid composition) and the sporadic availability of liquid water in University Valley apparently were factors in the evolution of this species.