StenocephalemysDivision. Myomys has traditionally been used for the species we list under Myomyscus, but the holotype of colonus (Brants, 1827), which is the type species of Myomys, is an example of Mastomys (Van der Straeten and Robbins, 1997), making Myomys a synonym of that genus. Shortridge’s (1942) Myomyscus is the next available name (see generic account of Mastomys). The species ruppi and albipes were listed in Myomys by Musser and Carleton (1993), but are here added to the Ethiopian Stenocephalemys (see accounts of those species). They also placed daltoni and derooi in Myomys, but here we transfer them to Praomys (see those accounts).

Even as reconstituted here, Myomyscus remains polyphyletic. Recent analyses of complete mtDNA cytochrome b sequences, for example, places M. verreauxii (type-species of the genus) as sister to Colomys and Zelotomys (although with weak support), brockmani as sister group to Mastomys and Stenocephalemys, and yemeni loosely and anciently related to Praomys verschureni (Lecompte et al., 2002b). By contrast, analyses of nuclear IRBP gene sequences cluster M. brockmani and M. yemeni and indicate it to be a sister group to Stenocephalemys (E. Lecompte, in litt., 2002); the IRBP sequences support the monophyletic cluster of M. verreauxii, Colomys, and Zelotomys. Cladistic analyses of morphological traits demonstrate Myomyscus (reported as Myomys) to be a sister-genus of Mastomys, with the two species sampled (fumatus [=brockmani] and daltoni [here placed in Praomys]) typical of tree savannas while species of Mastomys occupy grass savannas (Lecompte et al., 2002a). Chromosomal and immunological data related Myomyscus brockmani (reported as fumatus) to species of Mastomys (Qumsiyeh et al., 1990), morphometric analyses placed M. verreauxii closer to Mastomys than to other species of Myomyscus (Van der Straeten and Dieterlen, 1983; Van der Straeten and Robbins, 1997), and some researchers (e.g., Misonne, 1969, 1974; Qumsiyeh et al., 1990) included Myomys (now a synonym of Mastomys) and Myomyscus within Praomys. Analysis of microcomplement fixation of albumin grouped Myomyscus verreauxii (recorded as Myomys) with Mastomys, Praomys, and Hylomyscus (Watts and Baverstock, 1995a). Van der Straeten (in litt., 1994) considered Myomyscus to contain only verreauxii, a hypothesis consistent with molecular analyses (Lecompte et al., 2002b; Lecompte, in litt., 2002). We retain Myomyscus separate from Mastomys and Praomys, which accords with current research results (Lecompte et al., 2002a, b), and would welcome future morphological and molecular phylogenetic analyses incorporating a wide range of morphological traits and different genes along with denser taxon sampling that might finally define the contents of Myomyscus and test the cladistic affinity of M. verreauxii with species of Colomys and Zelotomys as indicated by mitochondrial and nuclear DNA sequences.