Naiazetes reevesi, a new genus and species of oribatid mite, is based on adult specimens from semi-aquatic habitats in eastern Quebec and Alabama. This genus is tentatively placed in the Zetomimidae based on the shared presence of an unusually large male genital sclerite in Naiazetes, Heterozetes and Zetomimus. Naiazetes shows unique sexual dimorphism, with differences in shape of the rostrum, and shape and position of genital papilla Va between male and female specimens.