Mastomys shortridgei St. Leger 1933

Mastomys shortridgei St. Leger 1933, Proc. Zool. Soc. Lond., 1933: 411.

Type Locality: N Namibia, Grootfontein Dist., Okavango-Omatako junction.

Vernacular Names: Shortridge's Mastomys.

Synonyms: Mastomys legerae (Ellerman, Morrison-Scott, and Hayman 1953) .

Distribution: Extreme NW Botswana and NE Namibia (Caprivi area) in the region of the confluence of Okavango and Kwito Rivers where it apparently inhabits reedbeds and swamp grasses (de Graaff, 1981:216; Skinner and Smithers, 1990:270); also E Angola, where the species is associated with marshes (Crawford-Cabral, 1998).

Conservation: IUCN – Lower Risk (lc).

Discussion: Karyotype (2n = 36, FNa = 50) similar to that of M. coucha (Granjon et al., 1997 b) . Taxonomy reviewed by Meester et al. (1986:285). Some workers considered shortridgei closely related to or the same as M. angolensis (see references cited in Meester et al., 1986). That species has five pairs of teats and most authors attributed the same number to M. shortridgei, but the latter has eight pairs (see references in Granjon et al., 1997 b). This is also a significant distinction for the generic allocation of shortridgei because Granjon et al. (1997 b) employed more than ten teats as one of the diagnostic traits of Mastomys and included shortridgei in the genus but excluded angolensis . A principal component analysis based on holotypes of the Mastomys-Praomys-Myomys-Hylomyscus complex also nested that of shortridgei deep within the cluster identified as Mastomys (Van der Straeten and Robbins, 1997) . Mastomys shortridgei occurs sympatrically with M. natalensis (de Graaff, 1997 q, 1997 s; Skinner and Smithers, 1990). Reviewed by de Graaff (1997 s) and Granjon et al. (1997 b), who also cited references describing chromosomal and spermatozoal distinctions between M. shortridgei and M. coucha .