Master's Theses



Degree Name

Master of Science (MS)


I investigated geographic and non-geographic variation among populations of the southern bog lemming, Synaptomys cooperi, in Arkansas, Iowa, Illinois, Kansas, Missouri, Nebraska, and Wisconsin using cranial morphometric data. I also reviewed the taxonomic history of S. cooperi, commenting on the fossil record and historical biogeography of the species with special reference to populations in the Great Plains Physiographic Region. Finally, I summarized the current status of S. c. paludis and S. c. relictus on the western Great Plains. The distribution of Synaptomys on the Great Plains is probably a result of post- glacial climatic changes and vegetational fragmentation that occurred after the Pleistocene. Based on cranial morphology, I detected no consistent sexual dimorphism in populations of S. cooperi. Variation among populations varied clinally in the reverse of Bergman's Rule, with individuals increasing in size from east to west and north to south. 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). Because of the paucity of specimens from the western Great Plains, taxonomic conclusions as to the intraspecific relationships of populations of synaptomys on the Great Plains are speculative. I therefore recommend that the current classification of S. cooperi on the Great Plains be followed until additional results, such as DNA sequencing information obtained from hair and skin of existing museum specimens, are available. No individuals of C. s. paludis and C. s. relictus have been collected since 1946 and 1968, respectively, and these taxa may be extinct. However, I recommend that additional trapping be conducted before these populations are recognized as extirpated.


Jerry R. Choate

Date of Award

Fall 1994

Document Type

Thesis - campus only access


© 1994 Gregory M. Wilson


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