A New Chipmunk (Genus Eutamias) from the Black Hills   By: John A. White

BY JOHN A. WHITE

University of Kansas Publications Museum of Natural History

Volume 5, No. 19, pp. 259 262 April 10, 1952

University of Kansas LAWRENCE 1952

UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY

Editors: E. Raymond Hall, Chairman, A. Byron Leonard, Edward H. Taylor, Robert W. Wilson

Volume 5, No. 19, pp. 259 262 April 10, 1952

UNIVERSITY OF KANSAS Lawrence, Kansas

PRINTED BY FERD VOILAND, JR., STATE PRINTER TOPEKA, KANSAS 1952

A New Chipmunk (Genus Eutamias) from the Black Hills

BY JOHN A. WHITE

Study of the chipmunks from the eastern Rocky Mountains and Great Plains reveals that the chipmunks from northeastern Wyoming and from South Dakota which Howell (N. Amer. Fauna, 52:55, November 30, 1929) referred to Eutamias minimus borealis actually belong to a heretofore unnamed subspecies which may be named and described as follows:

Eutamias minimus silvaticus new subspecies

Type. Female, adult, skull and skin, No. 20050 Mus. Nat. Hist., Univ. Kansas; from 3 mi. NW Sundance, 5900 ft., Crook County, Wyoming; obtained on July 4, 1947, by H. W. Setzer; original No. 1692.

Range. Bear Lodge Mountains in northeastern Wyoming and the Black Hills of South Dakota.

Diagnosis. Size large (see measurements); general tone of upper parts drab; sides Ochraceous Buff (capitalized terms are of Ridgway, Color Standards and Color Nomenclature, Washington, D. C., 1912); lateral stripes Fuscus Black washed with Ochraceous Tawny; ventral side of tail near (14' h ) Ochraceous Orange and fringed with black.

Comparisons. From Eutamias minimus pallidus (specimens from Buffalo in Johnson County, Ivy Creek, Rockypoint, Middle Butte, and South Butte in Campbell County, all in Wyoming, and Harrison, Sioux County, Nebraska), the subspecies to the southward, westward, and northward, E. m. silvaticus differs in: General tone of upper parts markedly darker, more reddish and less grayish; dorsal stripes darker; crown markedly darker. External measurements, and measurements and characters of the skull of the two subspecies, do not differ significantly. Unless otherwise specified all comparative material is in the Museum of Natural History of the University of Kansas.

From Eutamias minimus cacodemus (topotypes in the United States National Museum), the subspecies to the southeastward, E. m. silvaticus differs in the same manner in which it differs from E. m. pallidus , but the degree of difference is greater because E. m. cacodemus is even paler than E. m. pallidus .

From Eutamias minimus confinis (specimens from 17 1/2 mi. E and 4 1/2 mi. S Shell, 8500 ft., Big Horn County, Wyoming), E. m. silvaticus differs in: General tone of upper parts darker, more reddish and less grayish; sides of rump more reddish and less grayish; underside of tail more tawny; skull distinctly longer and broader across zygomata.

From Eutamias minimus borealis (specimens from 1 mi. NW of junction of Irons Creek and Laird River; N side Muskwa River, 4 mi. W Ft. Nelson, 1200 ft.; E side Minaker River, 1 mi. W Trutch; Beatton River, 115 mi. S Ft. Nelson; 5 mi. W and 3 mi. N Ft. St. John; S side Toad River, 10 mi. S and 21 mi. E Muncho Lake; all in British Columbia; and from Assineau River, 1920 ft., 10 mi. E and 1 mi. N Kinuso, Alberta), E. m. silvaticus differs in: Under side of tail more reddish; dorsal stripes less blackish; sides slightly paler (less tawny); nasals distinctly shorter; skull distinctly shorter.

Measurements. Average and extreme measurements of three adult males and 11 adult females of E. m. silvaticus from the type locality are, respectively, as follows: Total length, 190 (189 190), 207 (202 220); length of tail, 85 (81 90), 97 (82 105); length of hind foot, 31 (30 33), 32 (31 34); length of ear, 14 (13 16), 15 (14 17); weight, 45.7 (44.6 46.5), 55.7 (50.0 68.0); greatest length of skull, 32.0 (31.5 32.6), 32.3 (31.5 33.1); zygomatic breadth, 18.5 (18.5 18.5), 18.6 (18.2 19.0); least interorbital constriction, 6.9 (6.8 7.1), 7.0 (6.4 8.1); length of nasals, 9.4 (9.2 9.6), 9.6 (9.3 10.1).

Measurements of the type. Total length, 206; length of tail, 90; length of hind foot, 32; length of ear, 15; weight, 59.3; greatest length of skull, 32.6; zygomatic breadth, 18.6; least interorbital constriction, 6.4; length of nasals, 9.3.

Specimens examined. Total number, 28. Specimens from South Dakota are in the United States National Museum, and those from Wyoming are in the Museum of Natural History of the University of Kansas.

South Dakota: Custer Co. : Custer, 3; Lawrence Co. : Deadwood, 10.

Wyoming: Crook County : 3 mi. NW Sundance, 5900 ft., 14; 15 mi. ENE Sundance, 3825 ft., 1.

Acknowledgment is made of assistance, with the field work, received from the Kansas University Endowment Association.

Museum of Natural History, University of Kansas, Transmitted December 8, 1951.