Otomys jacksoni Thomas 1891
Otomys jacksoni Thomas 1891, Ann. Mag. Nat. Hist., ser. 6, 7: 304.
Type Locality: Uganda, crater of Mount Elgon, 13,200 ft.
Vernacular Names: Mount Elgon Vlei Rat.
Distribution: Restricted to Mount Elgon, ca. 3300-4200 m, Uganda and Kenya.
Discussion: Typically considered a subspecies of O. typus subsequent to Bohmann’s (1952) monograph (e.g., Misonne, 1974; Musser and Carleton, 1993). Although their lower incisors do possess two well-defined grooves, as in O. typus, the Mount Elgon populations contrast sharply in their smaller size, dark brown pelage, and M3 with only 7 laminae. Clausnitzer and Kityo (2001) recorded the species (as O. typus) as common in afro-alpine habitats, where it exists sympatrically with O. barbouri .