sentences:  Traditionally the phylogenetic inner relationships of tremarctines had "Plionarctos" and "Tremarctos" being basal groups with respect to a short-faced bear clade of "Arctodus" and "Arctotherium".A study of the affinities of bears belonging to "Arctotherium" indicates that they were more closely related to the spectacled bear than to "Arctodus", implying convergent evolution of large size in the two lineages.The following taxonomy of the tremarctine bears follow by Mitchell et al.