Two Psammobiont Species of Anomalohalacarus (Acari, Halacaridae) from South Korea

Abstract

Two psammobiont halacarids, Anomalohalacarus n. sp. and A. biformis Abé, 1996, are recorded based on both sexes from tidal fine sandy sediment on the coast of South Korea. Both species share common features such as an undivided posterior dorsal plate, two ventral setae on the posterior epimeral plate, two setae on the secondary palp, three bipectinate setae on tibia IV, and four ventral setae on tarsus I. However, Anomalohalacarus n. sp. is distinguishable from the latter species by having a pair of subgenital setae on the genital foramen in the female and seven branched perigenital setae on the genitoanal plate in the male, and the absence of areola posteriorly on the anterior dorsal plate, of which the feature of branched perigenital setae in the male is first reported in the genus Anomalohalacarus. The Korean specimens of A. biformis 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 Anomalohalacarus species, including the new species, based on morphological characters. The genus Anomolohalacarus is reported for the first time in South Korea.