Taxonomy of the Chipmunks, Eutamias quadrivittatus and Eutamias umbrinus

by John A. White

Specimens examined.—Total number, 36.

Wyoming: Albany Co.: 3 mi. ESE Brown's Peak, 10,000 ft., 2; 3½ mi. S Wood's Landing, 1.

Utah: Uintah Co.: PR Springs, 7,950 ft., 43 mi. S Ouray, Uintah-Grand county line, 1 UU.

Colorado: Jackson Co.: Mount Zirkel, 10,000 ft., on trail, 2 WC; Buffalo Pass, 10,380 ft., 1 WC; Buffalo Pass road, 10,130 ft., 1 WC. Larimer Co.: 2 mi. E Log Cabin, 7,450 ft., 1 WC; Estes Park, 7,600 ft., 1; 1½ mi. SW Estes Park, 1; 2½ mi. SW Estes Park, 2; 3½ mi. SW Estes Park, 1; 12 mi. SW Estes Park, 1. Rio Blanco Co.: 1 mi. NW Pagoda Peak, 10,400 ft., 1. Boulder Co.: Long's Peak, 7 BS; 1 mi. NE Ward, 10,000 ft., 1; 3 mi. S Ward, 9,000 ft., 5; ½ mi. E and 3 mi. S Ward, 9,400 ft., 1; 1 mi. S Gold Hill, 8,200 ft., 1. Clear Creek Co.: Davidson Mine, 3 mi. SW Idaho Springs, 1; Georgetown, 1 CM. Jefferson Co.: Silver Plume, 1 CM. Park Co.: Tarryall Creek Camp, 8,700 ft., 1 WC. Gunnison Co.: S side Crested Butte Mountain, 9,500 ft., 1 WC; mouth of Virginia Basin, Gothic, 1 FC.

Discussion

The chipmunks that heretofore have been assigned to the species Eutamias quadrivittatus are here assigned to two species, E. quadrivittatus and E. umbrinus, for the following reasons:

1. The baculum of E. quadrivittatus differs from that of E. umbrinus in having a narrow base (see figs. 3, 4). This difference permits any specimen which has an associated baculum to be readily identified to species.

2. The cranial breadth in the subspecies of E. quadrivittatus is significantly larger than in the subspecies of E. umbrinus.

3. Specimens of E. umbrinus are darker than any specimen of E. quadrivittatus.