TAXONOMIC STATUS AND BIOGEOGRAPHY OF THE SOUTHERN BOG LEMMING, SYNAPTOMYS COOPERI, ON THE CENTRAL GREAT-PLAINS

We assessed geographic and nongeographic variation among populations o f the southern bog lemming (Synaptomys cooperi) in Arkansas, Iowa, Ill inois, Kansas, Missouri, Nebraska, and South Dakota based on morpholog ical data, Univariate and multivariate analyses of 15 cranial characte rs revealed no consistent sexual dimorphism. Geographic variation in c ranial morphology of adults varied clinally, with individuals increasi ng in size from north to south and east to west, The largest individua ls overall were from southwestern Kansas (S. c. paludis) and southwest ern Nebraska (S. c. relictus), and the smallest individuals were from populations in eastern Illinois (S. c. gossii), We found only minor st eps in clinal variation of cranial morphology, which may be attributed to periodic or recent isolation, No individuals of S. c. paludis and S. c. relictus have been collected since 1946 and 1968, respectively, and these taxa may be extinct, Because of the paucity of specimens, ta xonomic conclusions as to the intraspecific relationships of populatio ns are speculative, We, therefore. recommend retention of the currentl y recognized subspecies S. c. gossii, S. c. paludis. and S. c. relictu s until genetic characters can be analyzed.