Oxymycterus Waterhouse, 1837 . Proc. Zool. Soc. Lond., 1837:21.

TYPE SPECIES: Mus nasutus Waterhouse, 1837 .

COMMENTS: Akodontine. Specific taxonomy needs full revision; nominal species here recognized follow Cabrera (1961), Reig's (1987) provisional tally of valid forms, and Hinojosa et al. (1987). Although initial studies of electromorphic variation support the monophyly of Oxymycterus and its placement as an akodont (Hinojosa et al., 1987; Patton et al., 1989), cladistic relationship with Abrothrix, Microxus, and certain Akodon needs further exploration. Studies addressing morphological definition of Oxymycterus include Carleton (1973), Hooper and Musser (1964a), Hinojosa et al. (1987), Vorontsov (1967), and Voss and Linzey (1981). Diploid number of species thus far karyotyped have proven to be identical (Vitullo et al., 1986).