Reviewed by de Graaff (1997z), Meester et al. (1986), and Skinner and Smithers (1990). The taxon longicaudatus was described as a species of Mystromys (Noack, 1887) and listed that way by G. M. Allen (1939), but Misonne (1966) determined the holotype to be an immature example of Mastomys natalensis, an identification accepted by de Graaff (1981) and Meester et al. (1986), and verified by multivariate analysis (Van der Straeten and Robbins, 1997, who noted the specimen is a young adult). See Meester et al. (1986) for type localities and taxonomic references of all described forms; Grubb (2001; see also Opinion 2005 of the International Commission on Zoological Nomenclature, 2002b) suggested that albicaudatus Geoffroy, 1803, is a senior homonym of Otomys albicaudatus A. Smith, 1834, a possibility that should be formally resolved. Found in fynbos, succulent Karoo, nama-karoo, grassland, arid savanna, and savanna woodland (Mugo et al., 1995).

Fossil relatives include Mystromys pocockei, and Proodontomys cookei, represented from Pliocene-Pleistocene australopithecine sites in South Africa (Avery, 1998; Denys, 1991; Pocock, 1987). Late Pleistocene fossils had been identified as the extinct M. hausleitneri, but Lavocat (1956) doubted that they could be separated from extant M. albicaudatus, a synonymy that Avery (1995, 1998) substantiated with new material from Gladysvale and Swartkrans caves. Proodontomys cookei has been collected with M. albicaudatus in those late Pleistocene sediments, and while the latter still occurs in South Africa, the former apparently became extinct between 1 and 0.7 million years ago (Avery, 1998). "Mystromys" also recorded from the Pleistocene of Namibia (Senut et al., 1992).