Megadontomys Merriam, 1898 . Proc. Biol. Soc. Washington, 12:115.

TYPE SPECIES: Peromyscus thomasi Merriam, 1898 .

COMMENTS: Peromyscine. Used variably as a genus until Osgood (1909) stabilized its taxonomic ranking as a subgenus of Peromyscus, and so followed by Hooper and Musser (1964b) and Hooper (1968b). Carleton (1980, 1989) viewed the relationships and differentiation of Megadontomys at the generic level (but see Rogers, 1983). Aspects of morphology studied by Carleton (1973, 1980), Hooper and Musser (1964b), and Linzey and Layne (1969, 1974). Karyological affinities evaluated by Rogers (1983), Rogers et al. (1984), and Stangl and Baker (1984b). Werbitsky and Kilpatrick (1987) reported relatively low levels of genetic similarity between the nominal forms.