Taxonomy of the Chipmunks, Eutamias quadrivittatus and Eutamias umbrinus

by John A. White

Description.—Color pattern: Crown Cinnamon-Buff mixed with gray; upper facial stripe Sepia; ocular stripe Chaetura-Drab; submalar stripe Fuscous Black mixed with Sayal Brown; ear black; anterior margin of ear Mars-Yellow, posterior margin grayish white; hairs inside posterior portion of pinna Dresden-Brown; postauricular patch Pale Smoke Gray; median dorsal dark stripe black; lateral dorsal dark stripe black mixed with Sayal Brown; outermost dorsal dark stripe obsolete, Buckhorn-Brown mixed with black; median pair of dorsal light stripes grayish mixed with Buckhorn-Brown; outer pair of dorsal light stripes creamy white; sides Buckhorn-Brown; rump Pale Smoke Gray mixed with Saccardo's Umber; dorsal surface of tail black mixed with Buckhorn-Brown; ventral surface of tail Sayal Brown; outermost edge of tail Light Buff; antipalmar surface of forefeet Warm Buff; antiplantar surface of hind foot Ochraceous-Tawny; underparts creamy white with dark underfur. Skull: Large, with strong zygomata; braincase well inflated. Baculum: As in E. u. umbrinus.

Comparisons.—From E. u. umbrinus, the subspecies from the Uinta and northern Wasatch Mountains in Utah, E. u. fremonti differs in: Sides darker; antiplantar surfaces of feet darker; postauricular patch grayer; crown more grayish; skull slightly larger.

From E. ruficaudus ruficaudus, the species and subspecies from western Montana, E. u. fremonti differs in: General tone of upper parts, sides, underside of tail, and feet, all darker in coloration; baculum shorter and proportionally twice as wide at base.

For comparison with E. u. montanus, see the account of that subspecies.

Remarks.—The geographic ranges of E. umbrinus fremonti and E. ruficaudus ruficaudus are allopatric and no specimens have ever been taken in the intermediate area to indicate whether or not these two species anywhere occur together. The bacula in the two species differ to the same degree as those of E. quadrivittatus and E. umbrinus. The differences between E. u. fremonti and E. r. ruficaudus are such that in my opinion, E. ruficaudus is a distinct species.

Specimens examined.—Total number, 58.

Montana: Park Co.: Beartooth Mountains, 2 BS.

Idaho: Bonneville Co.: Big Hole Mountains, 9,000 ft., near Irwin, 1 BS.

Wyoming: Yellowstone Park, 2. Park Co.: 16¼ mi. N and 17 mi. W Cody, 5,625 ft., 2. Teton Co.: 1 mi. E and ¼ mi. N Togwotee Pass, 9,800 ft., 2; Amphitheatre Lake, Teton Park, 1 MM; Flat Creek, 4 MM; head of Cache Creek, 4 MM; Jackson, Upper Arizona Creek, 2 MM; Flat Creek-Granite Creek divide, 6 MM; Flat Creek Pass, 1 MM; Flat Creek-Gravel Creek divide, 2 MM. Lincoln Co.: La Barge Creek, 9,000 ft., 2 BS. Fremont Co.: Togwotee Pass, 12; 12 mi. N and 3 mi. W Shoshoni, 4,650 ft., 1; Mosquito Park R. S., 9,500 ft., 17½ mi. W and 2½ mi. N Lander, 1; 17 mi. S and 6½ mi. W Lander, 8,450 ft., 3. Sublette Co.: 31 mi. N Pinedale, 8,025 ft., 2; W side Barbara Lake, 10,300 ft., 8 mi. S and 3 mi. W Fremont Peak, 4; 19 mi. W and 2 mi. S Big Piney, 7,700 ft., 5.

Eutamias umbrinus montanus new subspecies