New synonymy and redescription of Mastigus deustus (Thunberg) (Coleoptera, Staphylinidae, Scydmaeninae)

Basing on examination of type specimens and original descriptions, the status of primary types of two South African Mastigini is clarified: i) the type specimen of Mastigus deustus (Thunberg) (originally described in Notoxus), previously incorrectly treated as a holotype, was found to be a syntype; ii) the type specimen of Mastigus glabratus Klug previously treated as a holotype is in fact a syntype; iii) the specimen previously treated as a paratype of M. glabratus is not a primary type. Lectotypes for Notoxus deustus and Mastigus glabratus are designated, and M. glabratus is placed as a junior objective synonym of M. deustus. Mastigus deustus is redescribed, and its diagnostic characters, including the aedeagus, are illustrated.