Baiomys—Pygmy Mice // Neotoma—Woodrats // Onychomys—Grasshopper Mice // Peromyscus—Deer Mice // Reithrodontomys—Harvest Mice // Repomys—Repomys Mice
This subfamily of cricetids is represented in most North American habitats, unlike the arvicolines that tend to be oriented toward the northern temperate and arctic regions. Also unlike most of our arvicolines, the teeth are rooted and not prismatic. Most have more or less rounded cusps and are brachyodont; the exception is Neotoma, which has semi-prismatic, hypsodont cheekteeth that quickly wear to a flat surface. The shape of the infraorbital foramen in neotominines and sigmodontines differs from that of the arvicolines; in the former, there is a distinct notch visible from above (Fig. 1); in the latter, there is no such notch (Fig. 2). Our only genus of sigmodontines, Sigmodon, has a quite different cusp look to its teeth (Fig. 3).
Figs. 1-5 (left to right). Fig. 1. Left upper toothrow of Peromyscus, a neotominine. Fig. 2. Left upper toothrow of Neotoma, showing semi-prismatic, flat-topped teeth. Fig. 3. Left upper toothrow of Sigmodon showing typical occlusal surfaces. Fig. 4. Notch of infraorbital foramen, typical of neotominines and sigmodontines. Fig. 5. Arvicoline anterior skull showing the lack of a visible dorsal notch. Figures not to scale.
Neotoma is the most apt to cause confusion with arvicolines, but the teeth are considerably less complex, and most of the regional arvicolines have non-rooted cheekteeth.
Last Update: 8 May 2009