Autochthonous North American Musk Oxen <i>Bootherium, Symbos</i>, and <i>Gidleya</i> (Mammalia: Artiodactyla: Bovidae)

Abstract

The history of taxonomy of the autochthonous genera of North American musk oxen<i>—Bootherium, Symbos</i>, and <i>Gidleya</i>—is reviewed. The bases upon which taxonomic judgments within the group have been made are identified. These bases are reevaluated in the light of current information on patterns of ontogenesis, sexual dimorphism, postmortem alteration of skeletal remains, and spatial and temporal distribution of musk ox records. The bases used by taxonomists in the past to justify separation of this musk ox group into multiple genera and species can be explained best as indices of sexual dimorphism or postmortem weathering and abrasion. All nominal species within <i>Bootherium, Symbos</i>, and <i>Gidleya</i> are, therefore, placed in synonymy with the senior name in the group, <i>Bootherium bombifrons</i> (Harlan, 1825). A revised diagnosis is provided for the monotypic species.