University of Kansas Publications

Museum of Natural History

Volume 9, No. 13, pp. 385-388

May 12, 1958

A New Bog Lemming (Genus Synaptomys)

BY

J. KNOX JONES, JR.

University of Kansas
Lawrence
1958

University of Kansas Publications, Museum of Natural History

Editors: E. Raymond Hall, Chairman, Henry S. Fitch, Robert W. Wilson

Volume 9, No. 13, pp. 385-388
Published May 12, 1958

University of Kansas
Lawrence, Kansas

PRINTED IN
THE STATE PRINTING PLANT
TOPEKA, KANSAS
1958

27-3033

A New Bog Lemming (Genus Synaptomys)

BY

J. KNOX JONES, JR.

In the autumn of 1952, I obtained a southern bog lemming, Synaptomys cooperi, at Rock Creek State Fish Hatchery, Dundy County, in extreme southwestern Nebraska. This locality of record is the westernmost for the species in North America. Subsequently, I reported this specimen in the literature (Univ. Kansas Publ., Mus. Nat. Hist., 7:486, 1954), provisionally assigning it to Synaptomys cooperi gossii, the subspecies occurring in eastern Nebraska. In late November of 1956, J. R. Alcorn collected three additional bog lemmings at the Rock Creek Hatchery.

These specimens from Dundy County represent a relict population that differs in several characteristics from S. c. gossii, and that differs also from all other subspecies of the species. This relict population is, therefore, here given subspecific recognition.

Synaptomys cooperi relictus, new subspecies

Type.—Adult female, skin and skull, University of Kansas Museum of Natural History no. 51617, from Rock Creek State Fish Hatchery, 5 mi. N, 2 mi. W Parks, Dundy County, Nebraska; obtained November 1, 1952, by J. Knox Jones, Jr., original no. 995.

Distribution.—Known only from the type locality.

Diagnosis.—Size large for the species, both externally and cranially; dorsal pelage dark; nasals broadly flared anteriorly (especially broad in relation to nasal length); auditory bullae small; molariform tooth-rows and incisive foramina long.

Measurements (in millimeters).—External measurements of the type specimen, followed by those of another adult female (KU 72603), are: Total length, 141, 145; length of tail-vertebrae, 24, 21; length of hind foot, 20, 20; length of ear from notch, 11, 12. The type specimen weighed 46.3 grams. Cranial measurements were taken in the manner described by Wetzel (Jour. Mamm., 36:2-3, 1955) except that he did not record the occipitonasal length. These cranial measurements of the type and KU 72603 are: Occipitonasal length, 30.2, 29.8; condylobasilar length, 27.2, 27.1; zygomatic breadth, 18.1, 17.9; lambdoidal breadth, 14.2, 13.8; length of nasals, 8.2, 8.3; breadth of nasals, 4.2, 4.0; length of rostrum, 6.6, 6.6; breadth of rostrum, 6.1, 5.9; breadth of upper incisors, 4.6, 4.2; length of maxillary tooth-row, 8.5, 8.4; length of incisive foramen, 5.8, 5.5; interorbital breadth, 3.1, 3.5.

Comparisons.—From Synaptomys cooperi gossii (specimens from eastern Nebraska and eastern