Mylomys rex Thomas 1906

Mylomys rex Thomas 1906, Ann. Mag. Nat. Hist., ser. 7, 18: 304.

Type Locality: C Ethiopia, Kaffa, Charada Forest.

Vernacular Names: Ethiopian Mylomys.

Distribution: Recorded only from the type locality.

Discussion: The taxon rex, represented only by the holotype (a skin without skull), was described by Thomas (1906 c) as a species of Arvicanthis, but later "provisionally considered as a giant member of Desmomys " (Thomas, 1916 a:68). Dieterlen (1974) challenged the validity of rex, but Yalden et al. (1976) pointed out the features distinguishing the holotype from samples of D. harringtoni, and treated rex as another distinctive species endemic to Ethiopia. Musser and Carleton (1993:630) wrote that "Our study of the holotype skin reveals it to be a large and probably old adult of Mylomys that is not as brightly pigmented as most samples of that genus. Whether the holotype actually came from Ethiopia, or represents a separate species of Mylomys are unknown; we provisionally list rex in the synonymy of M. dybowskii ." Yalden et al. (1996) were content to adopt this provisional arrangement, but explained there was no doubt the specimen was collected in S Ethiopia, and that it "may indeed be specifically distinct from M. dybowskii, since the latter is generally considered to be a savanna form while the type of rex was apparently obtained in tropical deciduous forest at an altitude of 1800 m " and the speculation "that rex could be one of Ethiopia’s very few lowland forest endemics... may yet be proved correct, once further specimens become available." Lavrenchenko (2002) endorsed the possibility that rex may be a distinct species. We treat rex as a species, which is better than hiding a possible endemic in the synonymy of M. dybowskii; study of additional specimens will reveal its actual relationship to that widespread species.