2014-09-042014-09-041957-04http://hdl.handle.net/10539/15394Main articleThis is the first of a series to be devoted to the rodent fossils of South African caves. It is mainly concerned with a discussion of the Cricetid genus Mystromys, which forms the dominant element of the rodent fauna. The two sub-species of M. hausleitneri described by Broom are considered to be indistinguishable from each other; the species itself is distinguished by the dimensions of the teeth. The dentition of a new species, Mystromys darti, is fully described and the relations with Petromyscus are discussed.frrodent fossils, caves, dentitionArticle