Two psammobiont species of Anomalohalacarus (Acari, Halacaridae) from South Korea

Both species are similar to each other in sharing an undivided posterior dorsal plate, three and two setae on the anterior and posterior epimeral plates, respectively, three bipectinate setae on tibia IV, and four ventral setae on tarsus I. However, <i>A.angustus</i> sp. nov. is distinguished from <i>A.biformis</i> by the absence of areolae posteriorly on the anterior dorsal plate, a much more slender posterior dorsal plate, a pair of subgenital setae on the genital foramen in females, and seven branched perigenital setae on the genitoanal plate in males. The feature of branched perigenital setae in males is reported for the first time in the genus <i>Anomalohalacarus</i>. The Korean specimens of <i>A.biformis</i> agree well with the original description from Japan, except for the number of ventral bipectinate setae on tibia II. This study presents (re)descriptions of both species with detailed illustrations and provides a dichotomous key to <i>Anomalohalacarus</i> species, including the new species, based on morphological characters. The genus <i>Anomalohalacarus</i> is reported for the first time in South Korea.