Comments on the Taxonomy and Geographic Distribution of Some North American Rabbits

BY E. RAYMOND HALL and KEITH R. KELSON University of Kansas Publications Museum of Natural History Volume 5, No. 5, pp. 49–58 October 1, 1951 University of Kansas LAWRENCE 1951
University of Kansas Publications, Museum of Natural History Editors: E. Raymond Hall, Chairman, A. Byron Leonard, Edward H. Taylor, Robert W. Wilson Volume 5, No. 5, pp. 49–58 October 1, 1951 University of Kansas Lawrence, Kansas PRINTED BY FERD VOILAND, JR., STATE PRINTER TOPEKA, KANSAS 1951 23–7436

BY E. RAYMOND HALL AND KEITH R. KELSON
IN preparing maps showing the geographic distribution of North American lagomorphs, some conflicting statements in the literature have led us to examine the pertinent specimens of the Florida cottontail and the Audubon cottontail with results as given below. The study here reported upon was aided by a contract between the Office of Naval Research, Department of the Navy, and the University of Kansas (NR 161–791). Unless otherwise indicated, catalogue numbers are of the United States National Museum and most of the specimens are in the Biological Surveys collection of the Fish and Wildlife Service. Grateful acknowledgment is made to persons in charge of the collections for permission to use the collections under their charge.
Sylvilagus floridanus similis Nelson
1907. Sylvilagus floridanus similis Nelson, Proc. Biol. Soc. Washington, 20:82, July 22.
Our comparison of each of the Nebraskan specimens with specimens of S. f. mearnsi in comparable pelage from Iowa and with the type and topotypes of S. f. similis reveals that each of the specimens of which catalogue numbers are given above is clearly referable to Sylvilagus floridanus similis .
Because some mammalogists have suspected that intergradation between Sylvilagus floridanus similis and Sylvilagus nuttallii grangeri occurs along the eastern base of the Rocky Mountains, we have examined specimens which may throw light on this matter.
From S. f. similis (holotype and three topotypes), S. n. grangeri (eight practical topotypes from Redfern, South Dakota) differ as follows: Throat patch darker; hind foot shorter; ear (dry) from notch longer; rostrum narrower; posterior extension of supraorbital process enclosing a longer and wider space between it and the braincase; superior border of premaxilla straight in profile instead of convex dorsally; tympanic bullae more inflated; external auditory meatus larger (diameter of the meatus more, instead of less, than crown length of upper molars); posterior border of palate without, instead of with, spine.