FIGURE 7. Partial and complete cheek-tooth rows of Prodipodomys idahoensis showing arbitrary tooth-wear stages used to determine the age-frequency distribution of this species at MNA locality 318. All specimens shown are from MNA loc. 318; associated upper and lower jaws were used where possible to ensure equivalency of wear. The deciduous p4 (juvenile, stage J) and teeth in wear stage 4 were not recovered in the deposit; hypothetical drawings are provided for these categories (the dp4 of P. idahoensis is unknown; a drawing of dp4 from a modern Dipodomys merriami is shown). Drawings are realigned and are reversed from original specimens where necessary in order to be shown as right upper teeth and left lower teeth. See also Table 2 for crown height measurements of P4, p4, M1, and m1 at each of these stages of wear. White and stippled areas indicate enamel; hatched areas indicate dentine.