A New Bog Lemming (Genus Synaptomys) From Nebraska
BY
J. KNOX JONES, JR.
=University of Kansas= =Lawrence= 1958
=University of Kansas Publications= =Museum of Natural History=
Volume 9, No. 13, pp. 385-388
May 12, 1958
Editors: E. Raymond Hall, Chairman, Henry S. Fitch, Robert W. Wilson
PRINTED IN THE STATE PRINTING PLANT TOPEKA, KANSAS
1958
27-3033
A New Bog Lemming (Genus Synaptomys)
From Nebraska
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.