Abstract

Parsimony analysis of morphological data reveals that several species of acarid mites previously assigned to the genera Rhizoglyphus Claparède, Rhizoglyphoides Volgin and Mycetosancassania Klimov, and some undescribed species, represent a monophyletic group within the genus Sancassania Oudemans. The genera Rhizoglyphoides and Mycetosancassania syn. nov. are considered as junior synonyms of the genus Sancassania. Four new combinations are proposed: Sancassania rotundata (Nesbitt, 1944), comb. nov. (from Rhizoglyphus); Sancassania germanica (Berlese, 1921), comb. nov. (from Rhizoglyphus); Sancassania nidicola (Volgin, 1978), comb. nov. (from Rhizoglyphoides); and Sancassania grifolapholiotae (Klimov, 2000), comb. nov. (from Mycetosancassania). Sancassania nidicola and S. germanica are redescribed from type specimens, S. rotundata is redescribed from material from the USA (Michigan). Three new species are described: S. nesbitti, sp. nov., S.   ojibwa, sp. nov. (North America) and S. mironovi, sp. nov. (Northern Asia). This lineage, nidicola(grifolapholiotae(nesbitti, sp. nov. (germanica + mironovi, sp. nov.) (ojibwa, sp. nov. + rotundata))), probably originated in the Palaearctic region from relatively derived Sancassania with short supracoxal setae. The ancestor was probably polyphagous, dispersing on a variety of hosts. We hypothesise that S. nidicola, the most primitive species of the clade, may retain the ancestral ecology. The other members of the clade have specialised to feed on mushrooms and adapted their phenology to exploit this short-lived resource.