In the above image note the difference in the number of cheek teeth between Spermophilus and Tamias (5 and 4 cheek teeth, respectively).
Spermophilus
In the above image note the difference in the number of cheek teeth between Spermophilus
and Tamias (5 and 4 cheek teeth, respectively).
1. infraorbital foramen passes between zygomatic plate and side of rostrum
2. dorsal profile convexed, not depressed between postorbital processes
3. postorbital processes of frontal directed obliquely backward
4. zygomata flattened horizontally and converging anteriorly
5. upper tooth rows approximately parallel
6. molars not greatly widened
7. lambdoidal crest weakly to moderately developed
8. postorbital processes more wide spreading
9. interorbital and postorbital widths approximately equal
10. large tubercle (bump) situated on lower side of oval or triangular
infraorbital foramen
11. 22 teeth (1/1, 0/0, 2/1, 3/3)
Go to the Tamias skull identification page or the Tamias striatus species account page.