 Norwegian mycologist and polypore authority Leif Ryvarden suggested that due to its large, grooved spores, "Pachykytospora" was in a phylogenetically isolated position in the Polyporaceae, although it shows some affinity to the genus "Megasporoporia", with which it shares the same hyphal system and type of rot.Unlike "Pachykytospora", however, "Megasporoporia" has smooth spores.In a 2007 publication, Zmitrovich and colleagues suggested that there are nine species in the genus (and they described a tenth, "P. wasseri"); in 1994, Ryvarden and Robert Lee Gilbertson indicated five species.