Two new species of the genus Oligonychus Berlese, namely O. shojaeii sp. nov. and O. hamedaniensis sp. nov., are described from plane trees, Platanus orientalis L. (Platanaceae), in Hamedan, Hamedan province, Iran. Four species are re-described based on new Iranian material: O. afrasiaticus (McGregor, 1939), O. coniferarum (McGregor, 1950), O. punicae (Hirst, 1926) and O. saccharinus Baker & Pritchard, 1960. Among them O. saccharinus is the most important pest on sugarcane farms in southern Iran. All active life stages are described for all species except O. afrasiaticus, allowing us to confirm the ontogenetic patterns of leg setae in the Tetranychini. We refine the definition of the ununguis species group and discuss taxonomic problems relating to the members of this species group, and also regarding the identification of O. sacchari (McGregor, 1942) and O. saccharinus.
