USE OF MORPHOMETRIC ANALYSIS ON CUBONAVICULAR AND ASTRAGALI TO DIFFERENTIATE BISON SPECIES

Species-level taxonomic studies generally include detailed morphological descriptions of taxa. These descriptions have been based on nonmetric, subjective, visual comparisons of morphological traits regardless of whether diagnostic characters between species are quantitative or qualitative in nature. Currently bison species in the fossil record are determined by morphologic characteristics of the cranium and horn cores. This material is often fragmentary at sites which have yielded a wealth of postcranial elements that can be ascribed to the genus bison. Species-level determination on postcranial material is often decided based on size when more than one species is present. This study explores the potential of using the cubonavicular and astragalus in a geometric morphometric analysis to differentiate bison species. We will gather 16 2D landmarks from 150 cubonaviculars and 24 2D landmarks from 160 astragali from Pleistocene and Holocene sites in Idaho. Landmark data will be treated with Procrustes superimposition to remove all nonshape differences and then subjected to principal components analysis and linear discriminant function analysis. We believe this study will show whether the cubonavicular and astragalus can be used to differentiate to the species-level.