After a taxonomic revision in 2005 two other species were recognised in the genus, W. muriae (another xerophilic species) and the halophilic W. ichthyophaga. Wallemia sebi was distinguished from the other two in that it showed growth also on media without additional solutes, while W. ichthyophaga and W. muriae grow only in the present of additional solutes. In 2015 W. sebi was further split into W. sebi sensu stricto and three new species described as W. mellicola, W. canadensis, and W. tropicalis. The species differ in their conidial size, xerotolerance, halotolerance, chaotolerance, growth temperature regimes, extracellular enzyme activity profiles, and secondary metabolite patterns.
