New and interesting oribatid mites (Acari, Oribatida) phoretic on Aceraius grandis (Coleoptera, Passalidae) from Vietnam
Five oribatid mite species (Oribatida), phoretic on beetles, Aceraius grandis (Coleoptera, Passalidae) from Vietnam, are identified: two new species, belonging to the subgenera Graptoppia (Stenoppia) (Oppiidae) and Perscheloribates (Perscheloribates) (Scheloribatidae), are described; and three known species are Mesoplophora (Parplophora) flavida, M. (P.) polita and Ramusella (Sabahoppia) blattarum. Graptoppia (Stenoppia) luisi sp. nov. differs from all species of the subgenus by the presence of tridentate rostrum. Perscheloribates kontumensis sp. nov. differs from Perscheloribates curiosus Ermilov, 2016, Perscheloribates hanoiensis Ermilov & Starý, 2018 and Perscheloribates surigaoensis Corpuz-Raros, 1980 by the presence of body sculpturing, distinct setiform apex in bothridial setae and flexible notogastral setae. Species M. (P.) flavida, M. (P.) polita and R. blattarum, the subgenera Mesoplophora (Parplophora) and Ramusella (Sabahoppia), and the genera Mesoplophora and Graptoppia are recorded in Vietnam for the first time; the subgenus Graptoppia (Stenoppia) is recorded in the Oriental region for the first time. An identification key to known species of Graptoppia (Stenoppia) is given.