Key to the Shrews of New Mexico


1. Total teeth, 28; 3 unicuspids in each maxillary tooth-row: Notiosorex crawfordi.

1'. Total teeth more than 28; unicuspids more than 3 in each maxillary tooth-row: 2.

2. Total teeth, 30; 4 unicuspids in each maxillary tooth-row: Cryptotis parva.

2'. Total teeth, 32; 5 unicuspids in each maxillary tooth-row: (Sorex), 3

3. Third and forth unicuspids approximately equal in size: 4

3'. Third unicuspid obviously smaller than the fourth: 5

4. Each upper unicuspid tooth provided with a pigmented ridge running from apex of tooth lingually to the medial cingulum of tooth and there ending in a small pigmented cusplet; unicuspids uncrowded, broad, and not very high-crowned; underparts brownish or buffy (not whitish): Sorex cinereus.ventral view of shrew skull showing pigment and typical characters of shrews

Ventral view of skull of Sorex monticolus showing pigmented ridges and typical characters of shrews.

4'. Each upper unicuspid without lingually directed pigmented ridge or medial cusplet; unicuspids crowded, narrow (from front to back), appearing high-crowned; underparts whitish: 7

5. Condylobasal length 20 mm or more; hindfoot fringed with stiff hairs; blackish above, white below: Sorex palustris.

5'. Condylobasal length 18 mm or less; hindfoot without fringe of stiff hairs; grayish or brownish above, tan or gray below: 6

6. Condylobasal length less than 15 mm; total length usually less than 100 mm; hindfoot 11 mm or less: Sorex nanus.

6'. Condylobasal length more than 15 mm; total length more than 100 mm; hindfoot 12 mm or more: Sorex monticolus.

7. Each upper front incisor with a small medial tine: Sorex arizonae.

7'. Upper incisor without medial tines: Sorex merriami.

Key slightly modified from Findley et al. (1975).


Last Update: 27 Jul 2005