Otomys typus Heuglin 1877

Otomys typus Heuglin 1877, Reise in Nordost-Afrika, Vol. 2: 77.

Type Locality: Ethiopia, Gonder Province, Simien Mtns.

Vernacular Names: Ethiopian Vlei Rat.

Synonyms: Otomys degeni Thomas 1902; Otomys fortior Thomas 1906; Otomys helleri Frick 1914; Otomys malkensis Frick 1914 .

Distribution: Highlands, ca. 1800-4000 m, of NC (Gonder) to SC (Gamo Gofa, N Sidamo, and Bale) Ethiopia (Yalden et al., 1976:Fig. 32).

Conservation: IUCN – Lower Risk (nt).

Discussion: Dieterlen (1968) and Petter (1982) viewed typus as another variant of a highly polymorphic O. irroratus, a conclusion that conflicts with their morphological discrimination as presented elsewhere (e.g., Ansell, 1978; Bohmann, 1952; Kingdon, 1974 b; Misonne, 1974). Nonetheless, the synonyms listed and wide East African distribution as conveyed by the classifications of Bohmann (1952) and Misonne (1974) embrace such immense morphological heterogeneity that diagnosis as a single species is incomprehensible and geographically improbable. In our view, O. typus proper corresponds to those populations with grizzled brown pelage, a moderately vaulted skull, M3 with 8-9 laminae, and two strongly creased grooves on the lower incisors, a morphology endemic to the highlands of Ethiopia. Even so narrowly delineated, the conspecific stature of Ethiopian populations is highly suspect, as suggested by the karyotypic and allozymic diversity reported for Otomys in the Bale Mountains (Lavrenchenko et al., 1997; 2000). Whether the exceptional variation reported by those authors is partly attributable to the presence of the tropicalis elgonis complex (see above) at lower elevations or yet another species confused under O. typus requires further study. Ethiopia’s rugged landscape likely harbors at least three species of Otomys .