Taxonomic Status and Biogeography of the Southern Bog Lemming, Synaptomys cooperi, on the Central Great Plains

Abstract

We assessed geographic and nongeographic variation among populations of the southern bog lemming ( Synaptomys cooperi ) in Arkansas, Iowa, Illinois, Kansas, Missouri, Nebraska, and South Dakota based on morphological data. Univariate and multivariate analyses of 15 cranial characters revealed no consistent sexual dimorphism. Geographic variation in cranial morphology of adults varied clinally, with individuals increasing in size from north to south and east to west. The largest individuals overall were from southwestern Kansas ( S. c. paludis ) and southwestern Nebraska ( S. c. relictus ), and the smallest individuals were from populations in eastern Illinois ( S. c. gossii ). We found only minor steps 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, taxonomic conclusions as to the intraspecific relationships of populations are speculative. We, therefore, recommend retention of the currently recognized subspecies S. c. gossii, S. c. paludis , and S. c. relictus until genetic characters can be analyzed.