A review of the ecology and distribution of Protoribates (Oribatida, Oripodoidea, Haplozetidae) in Alberta, Canada, with the description of a new species.

The oribatid mite genus Protoribates Berlese (Haplozetidae) is reviewed for North America and the genus diagnosis is revised to account for the North American species, Protoribates robustior (Jacot, 1937) is redescribed and newly reported from western North America and a new species from Alberta is described. Protoribates haughlandae sp. n. is bisexual, heterotridactylous, and lives primarily in the peat soils of fens and bogs. Protoribates robustior is all-female, monodactylous, and occurs primarily in dry forests or in dry, treeless sites dominated by grasses, sedges, and shrubs. Both species feed on fungal hyphae and spores, but P. haughlandae also is an opportunistic predator and/or necrophage of small arthropods and P. robustior gut contents often include material that resembles plant cell walls. Examination of type specimens confirms that Protoribates prionotus (Woolley, 1968) is a junior synonym of the widespread Protoribates lophotrichus (Berlese, 1904). A key to differentiate Lagenobates from Protoribates and to identify the 7 species of the latter that are known or reported from North America is provided.