Mus (Nannomys) triton Thomas 1909

Mus (Nannomys) triton Thomas 1909, Ann. Mag. Nat. Hist., ser. 8, 4: 548.

Type Locality: Kenya, Mt Elgon, Kirui, 6000 ft (1830 m).

Vernacular Names: Gray-bellied Mouse.

Synonyms: Mus (Nannomys) birungensis (Lönnberg and Gyldenstolpe 1925); Mus (Nannomys) fors (Thomas 1909); Mus (Nannomys) imatongensis Setzer 1953; Mus (Nannomys) murilla (Thomas 1910); Mus (Nannomys) naivashae (Heller 1910) .

Distribution: N and E Dem. Rep. Congo, Uganda (Delany, 1975), Kenya (Hollister, 1919), S Ethiopia (Lavrenchenko, 2000; Yalden et al., 1996), Tanzania (Grimshaw et al., 1995; Stanley et al., 1998; Swynnerton and Hayman, 1951), Malawi (Ansell, 1989 b; Ansell and Dowsett, 1988), Tete Dist. of Mozambique (de Graaff, 1997 h; Smithers and Lobao Tello, 1976), Zambia (Ansell, 1978), and C and NE Angola (Crawford-Cabral, 1998).

Conservation: IUCN – Lower Risk (lc).

Discussion: Subgenus Nannomys . Listed as a questionable synonym of M. mahomet by Yalden et al. (1976:30), who were unsure about the equivalence of mahomet and triton and merely noted that Ethiopian samples previously identified as triton were really mahomet . Lavrenchenko (2000) claimed that M. cf triton from the Ethiopian Harenna Forest, along with Ethiopian M. mahomet, belong to the same cytotaxonomic group, which excludes true M. triton; Yalden et al. (1996) noted that M. triton and M. mahomet are sympatric in S Ethiopia but the former lives in forest, the latter in grassy forest clearings. The description of Mus birungensis (Lonnberg and Gyldenstolpe, 1925) mirrors the range of variation of M. triton in samples (in AMNH) we have examined from the Kivu region of E Dem. Rep. Congo. Considerable chromosomal polymorphism has been reported in samples identified as M. triton (Robbins and Baker, 1978) . Altitudinal distribution on Ugandan slopes of Ruwenzori Mtns reviewed by Kerbis Peterhans et al. (1998). Extant southern limit of species is Zambia and Tete Dist. of Mozambique (about 17 ES), but it was present in KwaZulu-Natal, South Africa up to about 60,000 years ago (Avery, 1991).