Cervus canadensis and C. elaphus: North American subspecies and evaluation of clinal extremes

The distinctiveness of each extant North American subspecies of C. elaphus (Linnaeus, 1758) was tested using craniometric data. To provide a context for interpretation of these data, the distinctiveness of North American C. elaphus from Eurasian C. elaphus was reassessed from existing data and conclusions tested. Mor­phometry variations in size, shape, and sexual dimorphism of adult crania were analyzed using combined male-female and independent male and female principal component analyses. North American subspecies do not represent natural biogeogra- phic variation as earlier presumed. Posterior classification error was highest for subspecies, but was lowest for a set of 6 Operational Taxonomic Units that recognized C. elaphus-Olympic, C. e/apftus-northern California and Oregon, C. claphus-eastern Washington, C. elaphus-Rocky mountain and Cascade mountain, C, elaphus-Sas- katchewan and Manitoba, and C. elaphus-centra\ California. Males and females differed in their sizes, shapes and affinities to other populations. Intracontinental differences in the kind and amount of sexual dimorphism reinforced the importance of measuring and contrasting male and female features in phylogeographic analyses. Use of existing nomenclature as a blind guide for comparative systematica and ecology and for conservation undermines the quality of research and conservation for C. ela­phus in North America. Previous arguments for a single-species circumgiobal cline do not take into account sexual dimorphism, behavior and reproduction. Major interconti­nental differences do exist between clinal extremes in behavior, in cranial size and sexual dimorphism in addition to semilethal Fi hybridization. All suggest C. elaphus and North American Cervus are different species. Whether the transition is smooth, whether stepped transitions occur, and whether "canadensis" correctly represents the species' distribution need verification.