Eligmodontia F. Cuvier, 1837 . Ann. Sci. Nat. (Paris), ser. 2, 7:169.

TYPE SPECIES: Eligmodontia typus F. Cuvier, 1837 .

SYNONYMS: Eligmodon, Heligmodontia .

COMMENTS: A phyllotine member closely allied to Calomys (Hershkovitz, 1962; Williams and Mares, 1978). Revised by Hershkovitz (1962), who synonymized all forms as E. typus . Morphological, chromosomal, and distributional evidence, however, supports a view of greater species diversity (e.g., Kelt et al., 1991; Mann, 1978; Mares et al., 1989b; Osgood, 1943). For example, Kelt et al. (1991) identified three chomosomal morphs to which they applied the names typus (2n=44), puerulus (2n=50), and morgani (2n=32). The association of names, particularly for typus and morgani, is based on the nearness of their sample localities to type localities. This is not the same as karyotyping topotypic animals or comparing karyotyped specimens to holotypes. In view of the complex interdigitation of specific ranges among the ridges and valleys of the southern Andes, the use of these chromosomal formulae as a diagnostic key to species identifications should be employed cautiously pending a full revision of the genus. Williams and Mares (1978) referred Graomys hypogaeus to synonymy under E. typus sensu lato and questioned whether the type is a composite specimen; resolution of its status and proper synonymy requires restudy of the holotype as part of a revision of Eligmodontia .