Marine hyadesiid mites from Gough Island

Two species of hyadesiid mite are reported from the marine littoral of Gough Island, in the South Atlantic Ocean. One species, Hyadesia benguelensis Marshall & Ugrasen, has been recently described from southern Africa, while the other is a new species. This new species is described herein (H. alexi n.sp.) and bears similarity to H. travei Fain (known from Îles Amsterdam, in the South Indian Ocean) and H. maxima Fain, Sømme & Block (known from South Georgia, in the South Atlantic). The description includes details for the female, both normal and heteromorphic male forms, and the tritonymph. The combination of characters observed in the new species raises questions concerning the validity of the three Hyadesia subgenera (Hyadesiella, Hyadesia, Parahyadesia).